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How does moisture get into homes ? Homeowner VERSION
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How does moisture get into homes ? Homeowner VERSION


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Slide presentation shows how moisture can enter homes through gravity, wind-driven rain, absorption, surface tension, moisture diffusion, hydrostatic pressure, defective windows, defective doors, …

Slide presentation shows how moisture can enter homes through gravity, wind-driven rain, absorption, surface tension, moisture diffusion, hydrostatic pressure, defective windows, defective doors, poorly installed siding or cladding, roof leaks, poor house maintenance, ice dam melts, flashing leaks, and other building component failures. Slide show was designed for the layman or home owner. This version is not scientific. This is an older picture slideshow was made in 2003. A new updated version of this slide show can be seen at Please go to Face book and subscribe to Marko Vovk for new daily posts. Please go to Youtube under the name Marko Vovk, Clevelandmold or ClevelandMarko and watch moisture related videos. Please subscribe to the Marko Vovk Youtube channel. If you would like to purchase CD’s go to the EBay and type in Home Inspection and look for Marko Vovk.

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  • MARKO WILL DO THIS SECTION It can get their through, heat flow, air flow, moisture, natural occurrences, chemical reactions, biological reactions, peoples living habitats, climate, building design, building construction, building maintenance. The building should be viewed as a complex system of interacting variables.
  • This is a digital image of a home that was struck by a tornado in the summer of 2002 in PORT CLINTONO OHIO. We define this as a large roof leak.
  • This is a digital image of a home that was struck by a tornado in the summer of 2002 in PORT CLINTONO OHIO. We define this as a large roof leak.
  • The roof was installed by a SEARS contractor because it leaked. After the new roof was installed, the roof still leaked. This roof was removed and replaced by a Sears contractor for the second time. After the new roof was installed the second time, the roof still leaked. This roof was removed a third time and replaced by a Sears contractor the third time. After this new roof was installed the third time, the roof still leaked. The leak lasted for so long, that fungal reservoirs developed and contaminated this home. The contractor and Sears were sued. Both parties settled for a tune of 80K. They should have fixed the chimney flashing initially. YOU MUST DETERMINE WHER YOU ROOF IS LEAKING BEFORE YOU REPAIR. ALWAYS IDNEFY THE SOURCE OF THE LEAK.
  • This slate roof was poorly was installed. Water leaked into indoor poor area. A mold abatement company was employed and repairs were in excess of $150,000. The roof is still bad and slates keep sliding off the roof. The slates installed were red in color and came from “Slate Valley”. This is 24 mile long and 6 mile wide valley that extends from Grandville, NY, and West Pawlet, VT. North to Fair Haven, VT. This area is known to produce colored slates that are known to be very durable. The red colored slates used on this dwelling came from the NY side of this valley in Washington County. This red slate quarry was discovered in 1850 and today is known to produce one of the most durable slates in the world. The general compound make up of red slate is 73.93 Silica, 1.74 Protoxide of iron 1.74 Peroxide of iron, 5.16 Alumina, .10 Manganese Oxide, 1.25 Ca Carbonate, 1.06 CA Sulphate, trace of Phosphoriic acid, 3.92 Alkalies (NA), 1.24 water and 1.43 Magnesia. This red smooth no flaking slate has an estimated 200-300 year estimated life if properly installed. The actual manufacturer longevity for this slate is 75 years and beyond. This means that minimal maintenance is required for the first 75 years. The slates used on this dwelling were 8 X 12 and square pattern size. These slates were installed in the conventional and most common “Standard Pattern” orientation. The home had an old red slate section and a new red slate section. Several samples of each slate vintage were sampled. The older slates were dirtier and had holes punched at 3 inches from the top. The newer slated had holes punched 4 inches from the top. The scope of the slate work was to install new slates over the new addition and perform maintenance to older slate roof. The contractor knew that new slates were to be used and knew that old slates were to be reused. Re-using old slates is a very common acceptable practice. Why would the contractor then order slates that had different pre-punched holes. When you have two different pre-punched holed slates, it makes installation more difficult and errors are more probable. This is significant, since, the head lap for the old slates can be 4 inches and the head lap for the new slates can only be 3 inches. All slates have a top, bottom, front and back. This is elementary, and all slate roofers know that slates have only one way to lay. If you put the slate in backwards, it will be smoother and not have beveled ends. Most importantly, if you put the slate in backwards, the pre punched nail holes would have the counter sink on the wrong side allowing the nail head to stick-out and not be countersunk. These stick-out or not countersunk nails will eventually wear out the overlaying slate and cause a hole. If you put the slate in up-side-down, than nail holes would be exposed. Exposed holes can leak. During our evaluation, we saw both of these improper installation techniques. The slate roofer ordered same size slates which usually are more expensive. Same size slates means all the slates have same length and same width. The slate roofer knows, that when you order same size slates, more cutting and punching of slates may be required. When you have random width slates you can pick pre cut widths that fit properly in the run. The roofer did not properly install the slate roof. When installing a slate roof, you are supposed to start at the edges or end or gable ends. You are to start with end starter slate or a full slate or a half slate. These starting ends should alternate with ½ size and full size slates. With this dwelling these new slates should be 4 inches or 8 inches. Due to the same size slates ordered, the slate contractor would have to measure the distance from the edge and proceed toward a dormer. Once the dimension is known, a math calculation is needed. Sometimes you’re fortunate they all fit evenly. Other times, your not fortunate, and you have to cut some or all of the slates. The reason for the minimum 4 inches starters is the exposure to wind. The wind rattles these end slates and causes them to become loose and crack. The slate contractor started with the wrong end at numerous areas and started at the right end at other areas giving the appearance that several men did not know what they were doing. In the wrong starting areas, the contractor started at the dormer and proceeded toward the weather exposed end. Additionally, the contractor did not do the math prior to nailing. Due to this circumstance, many end slates are only 1-3 inches in width at the weathered ends. This is not acceptable from the architectural standard nor is it acceptable from the installation standard. It is difficult to install 1-2 inch wide slates properly, not to mention on wind prone locations. You can expect roof end damage from wind for the life of this slate system. Due the above mentioned improper starting of the slate rows, many locations had less than a standard required 3 inch lateral lap. You cannot possibly get 3 inch lateral lap when you install 2 inch wide slates. Slate contractors have to spend more time in their calculations to achieve this proper 3 inch lateral lap. This roof had many areas that did not have this 3 inch lateral lap. Numerous locations on flashing had exposed nails. Exposed nail heads should be sealed. At several flashing locations, the flashing was not tight to the sheathing with large gaps. Water can leak into these exposed nail heads and loose flashing areas. Several locations had cupper flashing with holes that were not sealed. These are all not acceptable installations that lead to potential roof leaks. The flat roofing system was poorly installed in one of the column flat roof construction. The flat roof was not properly sloped and allowed water to pond. At numerous locations at the parapet roofing and flashing was not complete with exposed OSB or wood. Exposed wood will deteriorate over time and cause leaks. The flashing was not properly sealed at several locations exposing the structural wood sheathing. Areas also had sloppy cuts and were overfilled with foam in a can. These are all not acceptable installations that lead to potential leaks. The parapet top flashing system was sloppy. Several fasteners have begun to rust and several end flashing locations were poorly cut. These conditions can lead to future leaks. Several end slates were loose. One location on the new roof had a missing slate. In one other location, the slate became loose and slide into the dormer gutter. In a different location the slate was cracked and a sloppy repair slate was slid into place. Missing slates, loose slates and cracked slates will most defiantly have the potential to leak if gone unnoticed. Numerous slates were slightly elevated giving the appearance that the slates were nailed to tight. Slates are to be nailed loosely and allowed to hang on the nail shank. When nailed too tight, the slate lifts up giving it an slightly elevated appearance. This slate later will crack with age, snow loads, wind loads and pressure. While on the rooftop at numerous locations, tight slates were encountered. Slates should not be nailed tight due to high probability of cracking at the weak nail hole plane. At this time, many slates have cracked and have already been repaired. We informed that this new roof has had more cracked slates than the old existing slate system. The apron flashing under the dormers is not accessible and therefore not viewed. It is assumed that the slates are nailed over the apron flashing. These locations also have a superficial cupper counter flashing that is exposed and can be viewed. This counter flashing is cut too short and placed over the slates. This system is only superficial, since, it does not go under or on top of the siding. Water will drip off the dormer and travel to the step flashing or under the slate when the nails are located. Water should not be allowed to enter these locations due to potential leaks. The dormer gutters were not installed properly. They were installed too tight to the dormer edge flashing. In some instances, the dormer edge flashing was cut to accommodate these tight gutters. Due to gutters being to tight to the dormer edge flashing, water will travel down the dormer edge flashing and up into the gutter spilling water destroying it primary function. These conditions have potential to cause leaks indoors. The slate contractor is using cupper holding strips to secure repaired slates. These cupper holding strips are sometimes referred to as state hooks. During our first visit, these units were seen at many locations. New expensive roofs should not have cupper straps holding down slates. Additionally, these cupper holding strips, are not to be used in severe weather locations. Ohio is a severe weather location. In winter months, snow and ice will slide off the roof and flatten these holding strips. The slates will then fall from the rooftop. These cupper holding strips and very ductile and not rigged and can easily bend with sliding snow and sliding ice. This is not an acceptable repair method for a new state roof. A test site was conducted by the slate repair company on the front of the dwelling. Exposure of the overhang showed no ice garage protection. We were informed that ice garage protection should have been implemented. This location also had some unknown 6 mil plastic nailed into the system. This 6 mil plastic has no place in this slate roofing system. A metal ridge was installed to the slate roofing system. We were informed that the this metal ridge was face nailed and not all pre-drilled. We were also informed that many of these slates have cracked and were already repaired. Face nailing is not advised in this location and slate failure due to this method are probable. The ridge was caulked at the end joists. This is not an acceptable fastening technique. One locations had black tar repair. This type of repair is generally not acceptable for new slate installations. This type of repair is temporary and failure will occur many years prior to end of slate life. When repairing slate roofs repairs should be temporary . The round turret construction was sealed at joists with a red caulk. This is only a temporary sealing method. This caulking compound will fail premature of the slate roof. In conclusion this new state installation is sloppy and not installed to the industry standard of practice. It was installed in a fashion that is allowing failure and necessitate continual repairs. Many of the installation methods implemented, were substandard and not done according to the industry standard. Systems will continue to fail and necessitate repairs.
  • Dirty gutters overflow Poorly connected downspouts cause ponding. Poor attic ventilation or heat loss cause ice dams. Gutter and downspout maintenance is very important.
  • EVENT Ice dams and the chimney system. SITE OBSERVATION The roof had problems with ice dams. This was the north side of the dwelling. The insulation was disturbed in the center of the attic. On certain days, the snow would melt at the upper roof portion, directly over the area that had disturbed insulation. The heat would rise quicker here and melt the roof snow. The water would run down the roof shingles. On the north side, also a shade area, no soffit vents existed and the insulation was stuffed into the overhang. There is no cricket behind the chimney. It is inevitable that ice would form there. Ice formed, and when it melted, it would leak indoors and into the interstitial space. CONCLUSION This condition continues and causes indoor microbial contamination. The solution to this condition was adding more insulation in the attic area. Secondly, to install soffit vents and ridge vents to allow for air movement. Thirdly a cricket was added to the back of the chimney. The clients also installed heat cables on the roofing membrane for back up. This condition of wall mold was also corrected. The insurance company paid for all remediation and repair. Many of today’s policies cover water damage but do not cover mold.
  • EVENT New condominium that has a French door leak at the threshold. SITE CONDITION The French door had leaks that were causing damage to the sub-floor system. On a side note. The owners of this unit were getting sick in the unit. They though they were getting sick from this leaking door that was causing mold to amplify. The mold growth at this location was sparse and minimal. You should never assume that your clients know everything. Just because some mold exists at a leaking French door does not mean that he of she will become ill. You need to evaluate the entire environment. Our clients stated that they have been getting sick for the last four months. This just happened to be the entire winter of 2002. After asking some questions, we learned that these clients also purchased a ventless fireplace. We were also informed that the ventless fireplace was used daily with no windows open. CONCLUSION The photos depict common damaged from leaking patio, French or sliding doors. This damage generally transfers to the band joists, sub-floor and sill in the basement. This problem generally costs homeowners several thousand dollars to correct. But this condition was not making our clients sick. We tested the air after running this vent- less fireplace for six hours. The home was so tight, that minimal or virtually no air exchanges occurred. The oxygen supply was being depleted. We found that the CO2 levels were over 1500 PPM. The exterior levels are generally 350-400 PPM. The recommended interior levels should be less than 700 PPM. The 1500-PPM was excessive and caused drowsiness and other ailments. The clients never became ill after they used the unit with ventilation.
  • This is bondo on the index finger. The home owner filled in all the rotted window and doors with bondo.
  • The Marvin windows and doors were found to be defective. Most windows and doors in this dwelling had wood deterioration present. The window and door deterioration was caused by exterior moisture conditions. The windows and doors had poor initial paint application and allowed moisture to be absorbed by the wood frames. The wood frames became wet and saturated. These wet and saturated conditions allowed for microbial deterioration of wood frame members. This deterioration condition has been occurring for many years, due to several repair histories. Furthermore, this condition is a known nationally recognized problem with may lawsuits and class actions. Marvin windows treated their windows with a defective wood preservative called PILT. This product is defective and causes premature wood rot. Poor priming and painting augments this wood rot. The sliding door had window putty or glazing filled at the base. There was excessive amounts of putty or glazing used because you could actually dig it out of the door. The significant amount of wood filler in the door frame would have taken a special installation process. Most other windows and doors had caulking repairs. All of these repairs were covering or filling in rotted window or door wood. These caulking repairs were sloppy and rough and not from the initial construction. This home is too new to have deteriorated windows. Luxury homes should have windows that last 30-50 years. These windows are defective and are failing. Past owners, manufacture and contractors of this dwelling knew these conditions existed and therefore, made these unsuccessful attempts to bandage these conditions. These present window conditions have occurred to other dwellings in this geographical area and nationally. Building officials, the manufacture, builders, and many other home owners are not oblivious to these conditions. At this time, it is our professional opinion, that replacing all windows and doors is necessary to minimize future uncommon maintenance.
  • EVENTA closer look at mushrooms. Mushrooms are growing on a log in the salmon stream are okay. Mushrooms that are growing in your home are not okay. SITE CONDITION This mushroom was found in a fine home that was only two years old. The owners never knew this condition existed because this home has one of those fancy living rooms that no one ever used. The moisture content of the interior window wood was over 20%. The window was found to be defective due to a seal condition. This window had a slow leak every time it rained. The wood window faced the southwest and had plenty of light. The wood window served as a medium for the mushrooms just like the salmon stream log. Photo #1 mushrooms growing on a log at a Rochchester NY salmon stream.Photo # 2 Mushroom growing on the sash of a sliding window. CONCLUSION If the wind were blowing from the southwest direction during rainfall, the window would leak. Additionally, the wood window faced the southwest and had plenty of light. Mushrooms can make many people sick especially when they break apart. When you breakup a mushroom millions of spores are released. If a person that is immune compromised or a person with allergies is exposed, series health effects can occur. Check the window components for mold amplification. Furniture had to be move to access this window. It does not take a long period of time under the right conditions for the mushrooms to grow.
  • Mushrooms do not grow on vinyl siding. The mushroom is growing on the sheathing behind the siding. Mushrooms need a lot of water. The chimney cap is leaking and the OSB under the siding is saturated. This condition is also occurring on the north side.
  • The EIFS system leaked and moisture was trapped . You cannot see this damage until the siding is removed. All EIFS systems need to be moisture surveys. EIFS moisture gauges generally see for $800-$1200.
  • EVENT Mold found under front entrance porch. SITE OBSERVATIONS This was a small cellar room below the front entrance. Water leaked from the concrete ceiling and from the walls. The walls were painted and black mold was growing on them. This room was located on east side of the home. This room along with the entire home had severe odors. The mold condition at this location was caused by front entrance slab leaks. The ceiling was a concrete suspended slab that had shrinkage cracks. Water leaked through these ceiling cracks an into the basement. The foundation was also leaking due to the failed water proofing system. CONCLUSION The homeowner had to waterproof the entire front step area. The three front steps had to be removed, and replaced for this repair. The exterior walls were patched, sealed and parged. The drain-tile system was replaced. The entire suspended slab was sealed with an epoxy coating so it would no longer leach and absorbed moisture. The interior mold was removed and all wood shelving was discarded. It was discarded due significant mold reservoirs that were amplifying on these cellulose products. A de-humidifier was placed in this room and set to 50 % relative humidity. When humidity levels are lower than 50%, mold reservoirs have a difficult time amplifying.
  • EVENT Water leaking into the crawl space. SITE OBSERVATION The foundation walls were leaking at the lower block. A history of wet and dry puddle marks is seen throughout this entire crawl space location. Sometimes when looking for mold you find water. Water generally equals mold. In the lower digital image, you will see water marks at the masonry joints. This means that the hollow block is filled with water. This is a problem that will lead to microbial contamination. This block is causing high humidity during foundation evaporation. High humidity will cause dew points and condensation. Air testing for fungi would probably give positive results. CONCLUSION This crawl space needs to be waterproofed and purged of microbial contamination. You need to waterproof this area prior to any microbial abatement. The high humidity condition will spread to the upper home and could cause condensation in the attic. The attic had mold growth on the north side. When you have crawlspace moisture infiltration, you must always check all attic locations for condensation conditions.
  • EVENT Water in the ducts under slab SITE OBSERVATION The exterior windows were all fogged. The fogged windows were all condensating from the interior and not on the exterior. CONCLUSION You should always check first for CO or gas fired system problems. In this case no problem existed with gas or fossil fuel systems. On slab homes, you must consider the duct work condition. Ductwork under slabs is not desirable unless it is perfect. Many systems detach, settle and or pull apart. You must look in every floor register. Water in the ductwork is a serious problem. Check all rooms and all ductwork to see how extensive this condition may be. You do not need any fancy equipment to take photos. Most digital cameras fit in ducts. This duct shows many years of being flooded. It also shows contamination and fungal reservoirs. If you look at the ductwork you will see that the clay pipe used was not sealed at each joint. Water can enter at all joints. This water is evaporating in the home causing the windows to condensate on the interior. This condition has also caused the entire attic to become black mold covered. Mold is also amplifying behind the exterior walls. This home is in serious trouble.
  • EVENT Ducts under the slab. SITE OBSERVATION The gutters were leaking during a snow melt. A young couple just bought this home. On the day they moved in, they smelled gas and had it turned off for three days. Then the horror began. CONCLUSION The house became cold to about 38 degrees F. The gas leak was fixed and the gas was turned on. The home heated up to 68 degrees F. The siding started to drip water. The water was coming from behind the siding. Rust stains on the exterior siding indicated that this was not the first time the house leaked from the inside out. In the attic it was literally raining. You needed an umbrella. The under slab ductwork had four inches of water. The furnace was causing the duct water to evaporate and cause high humidity and dew points to form throughout the dwelling. Water was condensing in the walls, on the walls and in the attic. Within ten days, the entire home was filled with mold. Mold was on all walls, in all walls, on all household belongings, in the attic and under all carpets.
  • EVENT Sump pump failure. SITE OBSERVATION This sump pump failed due to the float getting wedged against the sump pit wall. The basement flooded and allowed the basement wood floor to become saturated. The owners were living in their Florida home at the time of sump failure. Luckily, the laundry room had a floor drain. Sump pumps fail frequently for many reasons. You should always see if you have any other floor drains in the basement that are independent of the sump pump. Make sure that these drains have no way of getting plugged up with basement debris. The best safety mechanism is a battery or water-pressure back-up sump pump system. CONCLUSION Every time the sump pump failed, some water would travel under the wood floor. After several months of this condition, We did not test the roots due to the client’s budget. The home had a de-humidifier and no other locations had bio-growth. All the floors on the basement level were abated and treated for mold.
  • EVENT Electricity was terminated leaving no power to the sump. SITE OBSERVATION This was a real estate owned property (REO). When we drove up to this property, we could actually “smell the mold” in the front yard. The lower level was contaminated with black slimy mold. Many of these molds were identified as mycotoxin and dangerous. The mold infected the entire home including attic. All REO properties are foreclosures or repossessions. The past owners get evicted and generally trash the home. The utility companies turn off the utilities then the sump pumps can not work. It rains and the home floods. The home is vacant and VHS (vacant home syndrome) takes the home over. The result is microbial contamination throughout. CONCLUSION The microbial growth was so significant that the entire interior was removed. All that was left was the studs, joists. After removal of drywall and sheathing, the home was inspected. Remarkably, all of the wood structural components were clean and free of visible mold. All timbers were sanitized and HEPA vacuumed. The entire structure was encapsulated with paint. It is prudent to install a battery backup sump pump.
  • EVENT A highly contaminated basement. SITE OBSERVATION When you entered this home you would smell a musty odor. No visual mold was seen until you entered into the basement. The basement was 100 % mold covered. At this point you look around and you realize that you are not wearing any PPE (personal protection equipment) This home was full of Penicillium, Aspergillus, and Stachybotrys . A perfectly healthy indiudual can become sensitized for life from exposures like this. CONCLUSION Anyone that enters and previews vacant contaminated homes are being exposed to potential mycotoxins or allergenic molds. It is imperative that all personnel that enter potentially contaminated homes wear personal protection equipment PPE’s. At minimum a respirator should be worn. Dust masks are not adequate and should not be used for mold protection. For your own protection it is advisable to carry and wear a respirator that is rated PL 100 or equivalent. A magenta colored cartridge should be effective when entering such conditions. However, there are those that only use carbon cassettes on their respirators. Respirable particles can cause lung disorders. Parents should be cautioned about bringing children into these homes.
  • Tee pees had no insulation and were not air tight. Early 1900’s homes had no insulation and were not air tight. New homes today are built with building materials that make homes very tight. EX. Lower photo, double E-glass windows, Tyvak, and etc.
  • Marko speaking on moisture effects on the home and IAQ
  • All these changes have significantly influenced homes today. The influence the occupants health. They influence the occupants safety.
  • This introduction of thermal insulation caused reduction of the drying potential of the building envelope. Now when homes get wet they cannot dry out as quickly as they did with older building designs. Moisture and vapor get trapped and cannot dissipate. It only takes 72 hours for microbial amplification to occur.
  • Insulation is stuffed into the soffit. The eaves are restricted. Result is poor ventilation. Poor ventilation and trapped moisture leads to condensation and dew points. Dew point on sheathing results in mold
  • This is a digital image of a photo of a crawl in Danville Indiana. The entire crawl was covered with 1 inch Styrofoam insulation. If you look closely you can see the water droplets dripping on the soil floor. The moisture is coming from dew point due to the insulation. Moisture is trapped between the foundation masonry block and stiff Styrofoam insulation.
  • Insulation is against the foundation wall. Moisture is being trapped and the wall is not aloud to dry. Notice the moisture stains and efflorescence behind the insulation. This wall also had 6 mil plastic insulation. This would not allow for any moisture to escape that would be trapped. This system is not forgiving. A forgiving wall would allow moisture to escape.
  • EIFS are relatively new to housing industry. The I in EIFS means insulation. Many of these systems are failing all over the country. They fail due to poor design, poor installation and poor drying capabilities. Simply moisture is trapped and cannot escape. Trapped moisture means mold.
  • This is an example of how mold gets behind the six-mil polyethylene plastic inner wall vapor barrier. This construction condition is very common in the south. It works better in the south due to the warmer climate. In the north or in mixed climate areas, this design may have problems. In an air-conditioned home in the summer, the air in the home is cooler than the outdoor air. The interstitial wall cavity will also be cool. If the home is pressurized the cool air travels to the exterior. The air becomes warmer and warmer as it moves to the exterior side. This air will eventually infiltrate through random holes. As the infiltrated air get warmer during its travel, its relative humidity also goes down. Warm air can hold more moisture than cold air and condensation will not be a factor. In conclusion, cool air that is escaping due interior pressurization will not cause interstitial mold or moisture problems in the summer season. However, if the reverse occurs, a serious condition will occur. We have an attic exhaust fan that is always on in the summer. We also have two eight inch ducts that travel to a furnace utility room for make up air purposes. The fan is sucking air out of the home and out of the utility room. The home is now de-pressurized. Now we are drawing warm moist outdoor summer air into the home. This warm moist air is infiltrating into this air-conditioned house. This warm air now is getting cooler as it travels through the interstitial space toward the interior. Remember the drywall is cool and we have a six-mil vapor barrier. Now the humid air gets cooler during its travel inward and the relative humidity goes up. It stops at the six-mil plastic vapor barrier and condensates. When the condensation becomes excessive it runs down to the sill plate. The water and moisture eventually deteriorate the interstitial space and mold amplification can begin.
  • Do the math: The temperature indoors is 75  F. The temperature outdoors is 95  F. The outdoor humidity is 70% RH. The temperature behind the drywall is 76  F. By using a psychrometric chart you find the incoming air dew point is 84  F. This is what the six-mil plastic interstitial vapor barrier looks like after you remove the drywall. The inside of the surface of the plastic is where the condensation will occur. Looking down into the wall cavity you can see the deterioration beginning. Then interstitial inside face of the OSB oriented strand board exterior sheathing wall is also starting to develop mold reservoirs. Let us now look at a couple different scenarios: Scenario one: A mixed climate home, summer day with high humidity, air conditioning on, home is depressurized, no six-mil plastic vapor barrier. Now this wall is more forgiving [1] and moist air can pass through to the interior. Sometimes, forgiving walls are better in mixed climate areas. Scenario two A mixed climate home, summer day with high humidity, air conditioning on, home is depressurized, no six-mil l plastic vapor barrier and interior vinyl wallpaper is installed. Now condensation occurs on the backside of the vinyl wallpaper. The vinyl serves as the new vapor barrier and moist air cannot pass through to the interior. This wall is not forgiving. Forgiving walls are better in mixed climate areas. Scenario three A mixed climate home, winter day, heat on, home is pressurized, no six-mil plastic vapor barrier. Now this wall is more forgiving and moist interior air can pass through to the exterior. When this interior moist air travels to the exterior it becomes cooler. Now the condensation will occur on the interstitial inner side of the exterior sheathing. Do the math: interior temperature is 69  F, outdoor temperature is 0  F, wall temperature on the drywall is 67  F. The exterior sheathing behind the siding is 9  F. A dew point will form on the inside wall of the exterior sheathing. [1] This means moist air can easily travels through a wall system without being stopped by a vapor barrier.
  • The air simply does not exchange. The interior air becomes stagnant and becomes contaminated within indoor pollutants. Moisture is produced every day within the dwelling. It now can no longer escape or be mixed with exterior air that may have less moisture.
  • In the old days, everything went up the chimney. That’s why homes with fireplaces always felt drafty. The newer homes are tight and air simply does not exchange. The gas fired systems produce many dangerous bi-products and moisture. One of the main bi-products of fossil fuel products and gas fired systems is moisture. Depressurized homes can cause spillage of these gas fired systems. This moisture in now stuck in a home with minimal air-exchanges.
  • Tight building that use TYVAK and insulated windows. Sheet goods make the home tights. In this second photo OSB was used for the sheathing. The lower photo is a powered driven furnace which utilizes a PVC vent that is vented to the exterior.
  • This is a new home built in 2001. When we removed the drywall,6-mil plastic and insulation, we found some mold. Moisture gets trapped in the interstitial space and cannot escape. This wall is not forgiving. Forgiving walls will allow moisture to pass through. This system is ok unless the home is depressurized. A high efficiency furnace, an attic fan, a bathroom fan can all cause the home to be depressurized. Depressurization means that the home is sucking air from the outside. Outside air in the summer means high humidity. High humidity means potential dew point conditions within the interstitial space. Dew points in the interstitial space means mold.
  • Typical high efficient hot water heater that is power driven. This unit will pull air out of the basement when the unit is heating water.
  • This furnace had a PVC vent pipe that was power driven. Many of these systems had leaks. This particular PVC effluent vent pipe is loose at most joints. The expansion and contraction of the PCV pipe cause failure at most joints. When this occurs, condensate will drip at joints and evaporate will vbe released indoors. Many of the early high efficiency heating systems have these problems. Although we are focused on moisture, these units also leaked poisonous by-products licke Carbon Monoxide.
  • Water can enter buildings from roof, wall, foundation, doors or window leaks. Leaking pipes, floods, sewer back-ups, and water accidents are also sources of water entry. We call these conditions significant events and unless the resulting water is not removed quickly there is likely to be mold growth on optimum mediums. Even more complex is mold development associated with moisture that condenses out of the air. All air contains moisture or grains of moisture. The moisture holding capacity of air is dependent on temperature. Warmer air can hold more moisture or grains of moisture than that of cold air. When air cools or loses heat, it will hold less moisture. Engineers have designed a chart called the psychrometric chart. A psychrometric chart graphically illustrates the relationships between air temperature and relative humidity as well as other properties. This psychrometric chart can be used for many applications. For our purpose, we will only use this chart for dew points and simple mold applications. We have simplified this chart for this books application. We will only be interested in four different variables: wet bulb temperature, dry bulb temperature, dew point and relative humidity. We will show the relationship that by knowing dew point we can predict mold amplifications.
  • EVENT Investigator is testing the air for humidity conditions using a portable sling psychrometer and electronic gauge. SITE OBSERVATION Always check the humidity of a home. The oldest and easiest gauge to use is a sling psychrometer. All you need to do is follow the simple directions. This gauge tells you what the humidity is in the home that is under question. This gauge is easy to use and costs less than one hundred dollars. You should have one of these units if you will be calculating humidity indoors. After you use this unit, for fifteen minutes your hand will become soar. It is very physical to use. Having a second electronic gauge is advised. Many companies make these units. The units can be purchased for fewer than one hundred dollars. CONCLUSION You need to have both gauges. The sling is never wrong but will tire your hand. The electronic unit is usually accurate, but can be biased if bumped or damaged. Use the sling for your first and last readings to keep your electronic unit calibrated. This is a good quality control measure. (SEE PSYCHROMETRIC CHART SECTION)
  • SITE OBSERVATION This was a single unit that existed in a ten-unit building. CONCLUSION Using a sling psychrometer seems a bit prehistoric when you have electronic gauges that tell you everything you need to know with a push of the button. Many times, the electronic gauges are slightly off or inaccurate. You should always take at least two additional tests using a sling to establish a base line or a calibration of your electronic gauge. You always want to take a reading in both the clean control area and the exterior environment. The sling will give you a wet bulb [1] temperature and a dry bulb [2] temperature. With these two values you can determine the humidity. These gauges can be purchased for less than one hundred dollars [3] [1] Wet Bulb Temperature The temperature reading that results when a thermometer's sensing bulb is fitted with sock saturated with water and placed in an air stream. As the water evaporates heat is removed from the bulb thereby reducing the temperature reading. When a condition of dynamic equilibrium is reach the rate of heat transferred from the passing air stream to the water equals the heat transferred from the water to the air stream via the evaporated water. [2] Dry Bulb Temperature Simply the temperature of the air stream or sample as measured by any standard temperature measurement device. [3] Call Professional Equipment Co see acknowledgements
  • EVENT Moisture meter test conducted because a window is defective and interstitial moisture migration is suspected. SITE OBSERVATIONS The owner of this home was concerned with moisture stains in his living room under several of the windows. You have to be very careful with windows manufactured between 1987 and 1993. Several name brand windows have been made with defective wood preservatives. Ten years later, the windows dry rot out and leak ( Serpula ). Most of the homes with these defective windows are upper middle income homes. You should check the Internet for the name brands and for the class action lawsuit information. We find that the owners of these types of windows repair the rot with bondo or wood filler and repaint them. This practice of concealment is widespread throughout the country. CONCLUSION Many times you cannot see the moisture and specialized equipment is needed. In the upper digital image a test was done above the window where leaking was not suspected. The readings were zero and dry. In the lower digital image the moisture readings were taken below the defective windows. The readings showed that moisture was present. This is a major problem due to the potential of interstitial moisture and fungal activity within the wall system. The use of moisture meters is critical in locating the source of water. Remember that water is necessary for the amplification of fungal reservoirs. We found that the more sensitive the moisture meter the higher the readings.
  • Dew point temperature is the temperature below which moisture will condense out of air. Air that is holding as much water vapor as possible is saturated or at its dew point. Water will condense on a surface, such as a building wall, attic sheathing, basement foundation or pitcher of ice water that is at or below the dew point temperature of the air. The dew point temperature scale is located along the same curved portion of the chart as the wet bulb temperature scale. However, horizontal lines indicate equal dew point temperatures. The dew point can also be read on the far left hand side of the chart. I like to draw a horizontal line all the way to this far left hand side. This entire horizontal line is the dew point that never changes, only the temperature changes. You can also draw this line horizontally to the far left hand side and dew point will still remain the same. Air will only hold so much moisture, the warmer the air the more the moisture it will hold. As air cools, it will hold less moisture. This moisture is called grains of water in the air. It is this dew point we are trying to determine. If we know the dew point, then we can predict mold or least know why the mold grew here and not there. If we understand dew point, we can alter it and stop potential mold reservoirs from forming. We will apply this concept to an example. You will need to know at least two variables to determine the dew point. You can purchase a sling psychrometer and spin this for three minutes and get the wet and dry bulb temperatures. It is very easy to use. This will give enough data to use the psychrometric chart to find the dew point. We like using electronic gauges because they automatically tell you the dew point. These gauges can be purchased for less than one hundred dollars. So now you ask, why then do you need this fancy difficult looking chart? You don’t, but the color chart looks great on reports. What it does do, is once you plot your point you can see a bigger picture and make projections and conclusions when condensation could or has occurred. If you have a litigation matter, you want to use the sling psychrometer and psychrometric chart. The sling will never be wrong unlike electronic gauges that may have deviations. The psychrometric chart will always be right unlike your calculator when you press the wrong button.
  • From the chart, the dew point is 61° F. This means that any surface that has a temperature of 61° F will start to condensate. If you were to water your grass with city water, the copper cold water line would eventually reach ground temperature. The ground temperature is 55° F for this geographical area. As the cold water runs through this pipe, the pipe gets cold and starts to condensate. If the insulation on your air conditioning suction line is damage it would start to condensate. The stains for this example are from pipes that are condensating above the living room ceiling in the interstitial space. You need to lower this interstitial space dew point. You can do this in two ways. The obvious is to remove the grains of moisture through de-humidification, or increase the air temperature in the home. Beware of sprinkler system piping above the ceiling.
  • From the chart the relative humidity is 48.1 %. In this question you can assume that the wall temperature is the dew point because the wall felt wet to the touch. The wall temperature is also at the ground temperature with is 55°F for this geographical area. It is difficult to answer the second part of the question. If the temperature drops during cooling season, the humidity will automatically increase and the dew point would still be 55°F. If the temperature increases during heating, then the humidity will decrease and the dew point would still be 55°F. The solution in this example it to dehumidify and remove grains of moisture out of the air. [1] [1] For further information contact us at our web site
  • Transcript

    • 2. Large roof leaks
      • Membrane failure
      • Flashing failure
      • Gutter or downspout conditions
      • Wind driven
      • Poor maintenance
      • Improper design
      • Ice dam melt
    • 3. Medium roof leaks
    • 4. Small un -detected roof leaks
    • 5. Some small roof leaks turn out to be huge damage.
    • 6. Gutter and downspout can cause problems.
    • 7. Ice dam
    • 8. Window and door leaks
      • Open windows or doors
      • Deteriorated windows and doors
      • Improper installations
      • Manufacture defects
      • Aluminum and Vinyl clad windows. (See video on Youtube called “Aluminum and Vinyl Clad Windows The Truth.)
    • 9. Poor door installation
    • 10. Defective windows and door
    • 11. Defective Marvin windows
    • 12. Leaking window mushroom
    • 13. Siding or building envelope leaks
      • Poor maintenance
      • Damaged
      • Defective
      • Poorly design
      • Missing
    • 14. Water behind the vinyl siding
    • 15. EIFS Corner of a home
    • 16. Cultured Stone Leaks
      • Poor window flashing
      • Missing Drainage Plane and Missing Drainage Space (Rain Screen)
      • See Youtube video called Cultured Stone The Truth
    • 17. Foundation / slab / grading leaks
      • Poor grade
      • Falling damp-proofing
      • Failing drain-tile
      • Cracks
      • Faulty construction
      • Poor design
      • Defective materials
    • 18. Foundation leak
    • 19. Crawl space leaks
    • 20. Foundation leaks cause duct floods
    • 21. Duct flood ruins home
    • 22. MARKO VOVK
      • This slide show is from 2003
    • 23. Plumbing and sump pumps leaks
      • Defective products
      • Product failure
      • Backup
      • Overflow
      • Poor maintenance
    • 24. Plastic pipes that become defective
    • 25. Plastic pipe failure cause mold
    • 26. Dishwasher leak
    • 27. Sewer back-up
    • 28. Improper drain discharge
    • 29. Water treatment leaks
    • 30. Sump pump failure
    • 31. Aftermath of sump pump failure
    • 32. Plumbing leak frozen pipes
    • 34. Moisture Effects in the Home
      • Poor Ventilation
      • Leaks in Building Envelope
      • Improperly Installed or No Vapor Barriers
      • No Local Exhaust in Kitchen/Baths
      • Occupants (Breathing, Perspiring, etc.)
      • Humidifier Set too High
    • 35. THE LAST 50 YEARS
      • Introduction of thermal insulation
      • Development of tighter buildings
      • Elimination of active chimneys
      • Introduction of forced air hearting and cooling systems.
      • Initially -- to reduce heat flows into and out of homes. GOOD
      • Later -- to reduce operating costs. GOOD
      • Reduced the homes drying potential. BAD
      • Now if homes get wet inside, it is difficult for them to dry out.
    • 37. Insulation condition that restricts ventilation
    • 38. Crawl Styrofoam wall insulation
    • 39. Insulation against basement wall.
    • 40. EIFS Exterior Insulated Fascia Systems
    • 41. Vapor barrier conditions
      • Missing vapor barriers
      • Damaged vapor barriers
      • Improper location of vapor barrier
    • 42. 6-mil plastic causes dew point on inside of wall. (Slide 1-3)
    • 43. Dew point occurs at optimal conditions and leaks. (Slide 2of 3)
    • 44. Moisture reads high in OSB (Slide 3 of 3)
      • Homes are more than twice as tight as they were 50 years ago.
      • Due to the introduction of new construction materials. (sheet goods, plywood, OSB, drywall, precast)
      • Desire to eliminate drafts.
      • Reduce energy costs.
      • Less dilution of exterior make up air.
      • New interior building components out gassing or releasing particulate. ( Formaldehyde, volatile organic compounds VOC’s, radon, carbon dioxide and other products .)
      • SBS (Sick Building Syndrome)
      • BRI (Building Related Illness)
      • Reduction in the ability for the stack effect or for the chimney to exhaust indoor pollutants.
      • Spillage of gas fire systems. (Moisture)
      • Electric furnace
      • Heat pumps
      • Power driven vented and sealed furnace
    • 53. Moisture Effects in the Home
    • 54. Moisture Effects in the Home
      • A psychrometric chart graphically illustrates the relationships between air temperature and relative humidity as well as other properties.
      • All air contains moisture or grains of moisture. The moisture holding capacity of air is dependent on temperature. Warmer air can hold more moisture or grains of moisture than that of cold air. When air cools or loses heat, it will hold less moisture.
    • 57. Equipment needed
    • 58. Sling usage
    • 59. Moisture meters
    • 60. Wet-Bulb Temperature
      • Wet bulb temperature reflects the cooling effect of evaporating water (Like drying your hands in one of those public bathroom wall push button air dryers). Wet bulb temperature can be determined by passing air over a thermometer that has been wrapped with a small amount of moist fabric. The cooling effect of the evaporating water causes a lower temperature compared to the dry bulb ambient air temperature. The wet bulb temperature scale is located along the curved upper left portion of the chart. The sloping lines indicate equal wet bulb temperatures.
    • 61. Dry-Bulb Temperature
      • Dry bulb temperature is the air temperature determined by an ordinary thermometer. The dry bulb temperature scale is located at the base of the chart. Vertical lines indicate constant dry bulb temperature. This is the unit the TV weatherman uses for temperature.
    • 62. Relative Humidity
      • Relative humidity is a measure of how much moisture is present compared to how much moisture the air could hold at that temperature. Relative humidity is expressed as a percent. Lines representing conditions of equal relative humidity’s sweep (happy smile curve) from the lower left to the upper right of the psychrometric chart. The 100 percent relative humidity (saturation) line corresponds to the wet bulb and the dew point temperature scale line. (This is the happy smile last curve on the far left side). The line for zero percent relative humidity falls along the dry bulb temperature scale line. Relative humidity is the unit that weathermen use in their weather reporting
    • 63. Dew Point Temperature
      • By knowing only two of the three above variables, we can predict dew point and visually graph it. It is this dew point that will allow us to predict mold growth
    • 64. Dew Point Temperature
      • Dew point temperature is the temperature below which moisture will condense out of air. Air that is holding as much water vapor as possible is saturated or at its dew point. Water will condense on a surface, such as a building wall, attic sheathing, basement foundation or pitcher of ice water that is at or below the dew point temperature of the air.
    • 65. EXERCISE ONE
      • The readings occurred in the living room of a slab home in the summer month. The ceiling in this room had odd long narrow moisture stains that resemble pool table stick marks. Where did these stains come from?
      • From your sling psychrometer, you have a dry bulb (DB) of 68° F and wet bulb (WB) of 64° F. What is the dew point?
    • 66.  
    • 67. EXERCISE TWO
      • From your laser infrared gauge you obtain a basement foundation surface wall temperature of 55°F. These gauges can be bought for about one hundred dollars. From your thermometer, you read a basement room temperature of 76°F. The basement walls have mold in the corners and on the base of the foundation walls. What is the humidity of the basement? In what season did this mold condition most likely occur?
    • 68.