Closed Crawlspace Construction
Services PowerPoint by Todd Witt
@ Synergy Airflow and Ventilation
LLC
(256) 350-1779
(256)...
For years, the building code incorrectly
required foundation vents. It assumed
that foundation vents bring in the
“good dr...
Crawlspace vents work fine in moderate,
dry climates. However, in the southeast,
warm, humid outside air enters through
ve...
Thermostatically controlled foundation vents
open in warm weather when they should be
closed. Foundation vents should alwa...
Issues we witness in traditional vented
crawlspaces…
• High humidity resulting in condensation that leads to
moisture, mol...
Condensation on wood framing promotes
“unidentifiable biological agent” growth due to
high moisture levels in the crawlspa...
Could rusted gas lines be an issue? This
house was less than 6 months old, on a flat
lot that was properly graded and drai...
Notice how water is “raining” from
this duct system in a vented
crawlspace. Notice the incomplete
ground cover.
•8
If there are problems outside of
the ducts, what is going on inside
the ducts?
•9
•10
•11
“Buckled” and “cupped” hardwood floors are
prevalent in vented crawlspaces. We witness
large amounts of money wasted in mi...
There is a lot of misinformation concerning why
hardwoods experience “buckling” and
“cupping”. Many companies sell and ins...
Other “crawlspace experts” sell
products such as the Wave, EZ
Breathe, and Humidex that pull air
from your home into your
...
Improper bulk water management
is the leading cause of building
failure in the U.S. and it must be
addressed first.
•15
Bulk moisture issues in
crawlspaces result from…
• Proper exterior grading is not provided.
• The interior grade of the cr...
Note that this crawlspace has a
lower interior grade than the
exterior grade.
•17
A lower interior grade than the
exterior grade “pools” moisture.
•18
When building your crawlspace..
• Always build up the interior grade several inches above the
exterior grade.
• Drain the ...
Notice that the lack of gutters
directs water straight into the
foundation.
•20
This sidewalk was trapping water
from lack of gutters and directing it
into the foundation.
•21
This homeowner paid us $30k to correct
the moisture issues caused by improper
grading and drainage. Get us involved
early ...
Money spent during construction on
gutters, proper grading, and french
drains can save thousands of dollars
later. It cost...
Interior footings and trenches
need to be backfilled so that they
do not collect water.
•24
We routinely see traditional fiberglass
insulation installed in vented,
improperly built crawlspaces. It
becomes wet and s...
Keep in mind that floor insulation doesn’t work
unless it is in complete contact with the sub-
flooring. Homeowners have s...
Notice where the moisture had been
trapped by kraft-faced/paper backing on
the traditional fiberglass insulation. We
remov...
Oftentimes we must clean the joist
with an anti-microbial agent and
wipe it down.
•28
Spray foam insulation stays in complete
and constant contact with the subfloor but
it has the potential to trap moisture i...
• I witnessed major vented crawlspace issues
growing up in the termite pretreatment and
insulation business.
• In 2003, I ...
A few of the lessons I learned…the
foam I installed in the block
deteriorated and I did not properly
air-seal and insulate...
Building scientists and building
codes now confirm that unvented,
sealed, conditioned crawlspaces
are the way to go!
•32
• Contact us and we will confirm your specific
building department’s code requirements.
• A 2” to 3” termite viewing strip...
We now leave the 3”-5”termite
viewing strip where the concrete
block meets the wood.
•34
We use can foam or caulk to seal the small
gap between the concrete block and wood.
This meets building code requirements
...
We recommend using a termite
bait system such as “Sentricon”
instead of a liquid applied termite
pretreatment.
• http://ww...
We use 10 mil black or white poly
as the vapor barrier. Keep in mind,
it is not a moisture barrier.
•37
• Installing a 20 mil poly pool liner inside of your crawlspace
looks great.
• It is overkill. Save the pool liners for po...
We are HVAC sizing and design
experts and we can show you…
• Creating a true air barrier and thermal barrier in the
underb...
• 50% of your home’s air originates in your crawlspace.
• This air is pulled in due to the “stack effect” –
conditioned ai...
In new construction, we are required to
install supply ducts. The air helps
condition the crawlspace and keep it dry.
It a...
We recommend a commercial grade
dehumidifier to help remove moisture that may
get into the crawlspace. These units require...
Appliance grade dehumidifiers do
not work in crawlspaces.
•43
Notice the height above of the ducts.
We see many homes with the supply
and especially the return ducts sitting
in standin...
Notice the multiple leaks around the ducts
from the package unit and how the
fiberglass is dirty from filtering the air
le...
Notice how the ductwork and
penetrations are completely sealed.
Unsealed penetrations are a common
entrance area for insec...
We routinely find leaking ducts.
Leaking supply and return ducts are
not as big of an issue when they occur
in an encapsul...
We install hygrothermometers with remote
sensors that monitor the humidity and the
temperature in the crawlspace as well a...
Hygrothermometers help us confirm..
• Whether HVAC systems are properly sized or
oversized.
• When additional dehumidifica...
• A “Synergy Home” with low humidity
and low moisture content controls dust
problems due to dust mites as well as
hardwood...
Closed crawlspace construction and
proper HVAC design helps control
Radon. Notice the improperly
installed venting above, ...
We inspect numerous homes with
clothes dryers and exhaust fans
vented into the crawlspace.
•52
We make sure construction debris
such as HVAC register cut-outs are
removed from the crawlspace and
not covered up in orde...
Properly installed sump pumps
with sump basins and french drains
are often necessary.
•54
We have found that wrapping the
piers completely is unnecessary.
This is proper detailing of a pier.
•55
As added safety, we recommend…
• Do not store combustion engines or toxic
substances in your crawlspace.
• Bi-yearly crawl...
When it comes to crawlspaces….
“out of sight, is out of mind” for
most homeowners but these
problems don’t magically go aw...
What is going on inside of your
crawlspace?
•58
Questions???
Contact Synergy Airflow and
Ventilation LLC for a free crawlspace
inspection and consultation.
Todd Witt (256...
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Closed Conditioned Crawlspace Construction

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Conditioned crawlspace construction is the way to go in the Southeastern US. We are the crawlspace specialists. Contact us at (256) 616-2264.

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  • Notice the floor joists. When I first examined the house there was so much air moving through the foundation, I thought the HVAC ducts were disconnected.
  • What happens if the interior grade is higher than the exterior grade?
  • It is almost impossible to install insulation in contact with the subfloor.
  • Indoor air quality is becoming a major issue in homes, schools, etc
  • What do you think the interior coils look like?
  • My monitor is located next to my coffee maker. Notice how clean the joists are.
  • Wet bulb is the temperature of evaporation. Dewpoint is the temperature of condensation. Saturation point is where dry bulb temperature = wet bulb temperature
  • Closed Conditioned Crawlspace Construction

    1. 1. Closed Crawlspace Construction Services PowerPoint by Todd Witt @ Synergy Airflow and Ventilation LLC (256) 350-1779 (256) 616-2264 Todd@SynergyAirflow.com •1
    2. 2. For years, the building code incorrectly required foundation vents. It assumed that foundation vents bring in the “good dry air” and let out the “bad wet air”. •2
    3. 3. Crawlspace vents work fine in moderate, dry climates. However, in the southeast, warm, humid outside air enters through vents, hits a cool interior surface, and condensation occurs. •3
    4. 4. Thermostatically controlled foundation vents open in warm weather when they should be closed. Foundation vents should always be closed, or better yet, eliminated. •4
    5. 5. Issues we witness in traditional vented crawlspaces… • High humidity resulting in condensation that leads to moisture, mold, structural, and indoor air quality issues. • Musty odors. • Condensation or “sweating” on air conditioning ductwork and equipment, insulation, water pipes, gas pipes, electrical wires, and framing. • Buckled and cupping hardwood floors. • Insect, termite, rodent, and animal problems. • Spray foam installed in the underbelly. • Improperly installed fiberglass batt insulation. • Cold floors. • Motorized foundation vents installed in an attempt to dry out wet crawlspaces. •5
    6. 6. Condensation on wood framing promotes “unidentifiable biological agent” growth due to high moisture levels in the crawlspace. Wood rot is caused by fungi that break down the cellular structure of wood. Keep in mind that wood decay known as dry rot will not occur without moisture. •6
    7. 7. Could rusted gas lines be an issue? This house was less than 6 months old, on a flat lot that was properly graded and drained. Notice the deteriorating wood flooring system. •7
    8. 8. Notice how water is “raining” from this duct system in a vented crawlspace. Notice the incomplete ground cover. •8
    9. 9. If there are problems outside of the ducts, what is going on inside the ducts? •9
    10. 10. •10
    11. 11. •11
    12. 12. “Buckled” and “cupped” hardwood floors are prevalent in vented crawlspaces. We witness large amounts of money wasted in misguided attempts to fix the symptoms instead of the underlying issues. •12
    13. 13. There is a lot of misinformation concerning why hardwoods experience “buckling” and “cupping”. Many companies sell and install motorized foundation vents that greatly increase moisture levels by pulling in hot, humid air and wasting electricity. •13
    14. 14. Other “crawlspace experts” sell products such as the Wave, EZ Breathe, and Humidex that pull air from your home into your crawlspace and create multiple issues and should be avoided. See www.greenbuildingadvisor.com for more info. •14
    15. 15. Improper bulk water management is the leading cause of building failure in the U.S. and it must be addressed first. •15
    16. 16. Bulk moisture issues in crawlspaces result from… • Proper exterior grading is not provided. • The interior grade of the crawlspace being much lower than the exterior grade and as a result it “pools” water. • There are no gutters installed. • Proper interior and exterior drainage is not provided. • HVAC condensate is not properly drained away from the crawlspace. • Landscaping material such as mulch is built up around the exterior of the foundation. • Sprinkler systems direct water against the foundation. • Exterior “damp-proofing” is not provided. •16
    17. 17. Note that this crawlspace has a lower interior grade than the exterior grade. •17
    18. 18. A lower interior grade than the exterior grade “pools” moisture. •18
    19. 19. When building your crawlspace.. • Always build up the interior grade several inches above the exterior grade. • Drain the foundation to its lowest point. • Consider “french drains” and sump pumps for added safetly. • Add an additional row or two of concrete blocks. • Install multiple crawlspace accesses. • Install a “sacrificial layer of poly” during construction. • Control bulk water entry during construction. • Do not build up flower gardens around the foundation that can hold moisture and slope them properly away from the home. • Keep sprinklers from wetting the foundation. • Use gutters and extend them from the foundation. • Drain HVAC condensate away from the foundation. •19
    20. 20. Notice that the lack of gutters directs water straight into the foundation. •20
    21. 21. This sidewalk was trapping water from lack of gutters and directing it into the foundation. •21
    22. 22. This homeowner paid us $30k to correct the moisture issues caused by improper grading and drainage. Get us involved early in your construction project! •22
    23. 23. Money spent during construction on gutters, proper grading, and french drains can save thousands of dollars later. It costs much more to fix later! •23
    24. 24. Interior footings and trenches need to be backfilled so that they do not collect water. •24
    25. 25. We routinely see traditional fiberglass insulation installed in vented, improperly built crawlspaces. It becomes wet and serves as a medium for “unidentified biological agents”. Notice I didn’t say the “M” word. •25
    26. 26. Keep in mind that floor insulation doesn’t work unless it is in complete contact with the sub- flooring. Homeowners have spent millions of dollars for a product that is not working. The 2009 IRC requires insulation to be in complete contact with the floor system. Installed improperly Moisture and gravity •26
    27. 27. Notice where the moisture had been trapped by kraft-faced/paper backing on the traditional fiberglass insulation. We remove existing fiberglass insulation and dispose of it. •27
    28. 28. Oftentimes we must clean the joist with an anti-microbial agent and wipe it down. •28
    29. 29. Spray foam insulation stays in complete and constant contact with the subfloor but it has the potential to trap moisture if there is a water leak. •29
    30. 30. • I witnessed major vented crawlspace issues growing up in the termite pretreatment and insulation business. • In 2003, I built one of the first, if not the first, closed crawlspace construction homes in Alabama. • I knew almost immediately that this was the way to build crawlspaces. • You would be comfortable taking a sleeping bag and spending the night in one of our crawlspaces. • Can you say that about your crawlspace? •30
    31. 31. A few of the lessons I learned…the foam I installed in the block deteriorated and I did not properly air-seal and insulate my band joist. •31
    32. 32. Building scientists and building codes now confirm that unvented, sealed, conditioned crawlspaces are the way to go! •32
    33. 33. • Contact us and we will confirm your specific building department’s code requirements. • A 2” to 3” termite viewing strip is required. • Contact your termite company before installing a closed crawlspace system. • Note that several of the termite companies that refuse to guarantee these systems actually sell foundation vents in an attempt to dry out the crawlspace. •33
    34. 34. We now leave the 3”-5”termite viewing strip where the concrete block meets the wood. •34
    35. 35. We use can foam or caulk to seal the small gap between the concrete block and wood. This meets building code requirements and is accepted by termite control companies. We will be happy to confirm the details with your termite control company. •35
    36. 36. We recommend using a termite bait system such as “Sentricon” instead of a liquid applied termite pretreatment. • http://www.sentricon.com/ •36
    37. 37. We use 10 mil black or white poly as the vapor barrier. Keep in mind, it is not a moisture barrier. •37
    38. 38. • Installing a 20 mil poly pool liner inside of your crawlspace looks great. • It is overkill. Save the pool liners for pools. • It is incredibly expensive. • It does not pass code in new construction. • It fails to air seal the rim joist/band joist where much of the air leakage occurs. • 10 mil poly works as well as a pool liner. • We install 1 ½ - 2” of closed cell foam on your interior foundation walls and rim joists/band joists for less money. • That leaves you added money to spend on a home energy audit that helps ensure your home is “Synergized”. • There is rebate money available well as low interest rate loans for existing construction. Why we don’t recommend 20 mil pool liners…. •38
    39. 39. We are HVAC sizing and design experts and we can show you… • Creating a true air barrier and thermal barrier in the underbelly of your subflooring is almost impossible. • Moving your HVAC unit and ducts into the thermal barrier such as a closed, conditioned crawlspace greatly reduces your heating and cooling load. • Moving your ducts inside the thermal envelope eliminates the code required need to duct test and reduces R8 duct insulation requirements. • The advantages of all-electric heat pumps and why atmospherically vented/B-vented gas appliances cannot be located in your crawlspace. •39
    40. 40. • 50% of your home’s air originates in your crawlspace. • This air is pulled in due to the “stack effect” – conditioned air leaks out through ceiling penetrations and is replaced by unconditioned air in the crawlspace. • The lack of fresh air ventilation multiplies the problem. • The lack of returns or jumper ducts in bedrooms multiples the problem. • Leaking ducts outside of the conditioned space multiplies the problems. • Encapsulating the attic with spray foam helps eliminate the “stack effect”. •40
    41. 41. In new construction, we are required to install supply ducts. The air helps condition the crawlspace and keep it dry. It also warms the floor in the wintertime making it more comfortable. •41
    42. 42. We recommend a commercial grade dehumidifier to help remove moisture that may get into the crawlspace. These units require routine maintenance. •42
    43. 43. Appliance grade dehumidifiers do not work in crawlspaces. •43
    44. 44. Notice the height above of the ducts. We see many homes with the supply and especially the return ducts sitting in standing water. Well above grade! Sitting in water and mud! •44
    45. 45. Notice the multiple leaks around the ducts from the package unit and how the fiberglass is dirty from filtering the air leakage. What do you think the interior HVAC coil looks like? •45
    46. 46. Notice how the ductwork and penetrations are completely sealed. Unsealed penetrations are a common entrance area for insects, spiders, small animals, and snakes. •46
    47. 47. We routinely find leaking ducts. Leaking supply and return ducts are not as big of an issue when they occur in an encapsulated, conditioned crawlspace instead of outside the thermal envelope. •47
    48. 48. We install hygrothermometers with remote sensors that monitor the humidity and the temperature in the crawlspace as well as the home. Keep in mind that relative humidity tells us how close the conditions are to saturation at a specific temperature. •48
    49. 49. Hygrothermometers help us confirm.. • Whether HVAC systems are properly sized or oversized. • When additional dehumidification needs to be added or if there are issues with the dehumidifier. • High interior humidity issues that cause dust mites and poor indoor air quality. • If there are moisture issues such as water leaks in the crawlspace. •49
    50. 50. • A “Synergy Home” with low humidity and low moisture content controls dust problems due to dust mites as well as hardwood floor and carpet issues. • Carpet and carpet pads are a main contributor to dust mites and indoor air quality issues. • We recommend installing a central vacuum system. •50
    51. 51. Closed crawlspace construction and proper HVAC design helps control Radon. Notice the improperly installed venting above, instead of below, the ground cover. •51
    52. 52. We inspect numerous homes with clothes dryers and exhaust fans vented into the crawlspace. •52
    53. 53. We make sure construction debris such as HVAC register cut-outs are removed from the crawlspace and not covered up in order to prevent attracting termites. •53
    54. 54. Properly installed sump pumps with sump basins and french drains are often necessary. •54
    55. 55. We have found that wrapping the piers completely is unnecessary. This is proper detailing of a pier. •55
    56. 56. As added safety, we recommend… • Do not store combustion engines or toxic substances in your crawlspace. • Bi-yearly crawlspace inspections. Immediately inspect anytime flooding occurs. • Inform other trades not to disturb the ground cover or spray foam. • Strongly against using inexperienced contractors that lack proper understanding of building science principles for your closed crawlspace construction. •56
    57. 57. When it comes to crawlspaces…. “out of sight, is out of mind” for most homeowners but these problems don’t magically go away. Most often, they get worse…much worse. •57
    58. 58. What is going on inside of your crawlspace? •58
    59. 59. Questions??? Contact Synergy Airflow and Ventilation LLC for a free crawlspace inspection and consultation. Todd Witt (256) 616-2264 Office (256) 350-1779 WeTestOthersGuess.com •59

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