Downloaded 132 times
Uploaded byRimpi Baro
Cavity walls
Cavity walls consist of two masonry skins separated by a hollow space. The cavity serves to drain water out of the absorbent masonry skins through weep holes. Cavity wall insulation such as mineral wool, polystyrene beads, or urea formaldehyde foam is used to reduce heat loss by filling the air space. Wall ties connect the two skins to prevent separation, and are spaced according to building regulations. Weep holes above windows and doors allow moisture in the cavity to escape. Cavity walls provide advantages like insulation from sound and moisture, reduced heat transfer, and lower foundation loads.
More Related Content
Cavity walls
- 1.
- 2. Main functions ofwalls 1. Strength 2. Stability 3. Weather exclusion 4. Thermal Insulation 5. Sound Insulation 6. Durability 7. Fire resistance 8. Appearance
- 3. CAVITY WALL: • Cavitywalls consist of two 'skins' separated by a hollow space. • The skins are commonly masonry such as brick or concrete block. • Masonry is an absorbent material, and therefore will slowly draw rainwater or even humidity into the wall. • The cavity serves as a way to drain this water back out through weep holes at the base of the wall system or above windows
- 4. CAVITY WALL INSULATORS: • Cavity wall insulation is used to reduce heat loss through a cavity wall by filling the air space with material that inhibits heat transfer. The internal and external leaves should have at least 10cm thickness • The three most common types of cavity wall insulation used are: • Blown mineral fibre. • Polystyrene beads or granules. • Urea formaldehyde foam. • Lean concrete
- 6. CAVITY WALL INSULATORS: • The Government regards cavity wall insulation as one of the most effective energy saving measures that you can carry out to your home and as well as saving you money it helps reduce emissions of carbon dioxide, the main greenhouse gas causing climate change. • This is because up to 35% of the heat loss from your property is through the walls.
- 7. Return corner ofa cavity wall in stretcher bond including wall ties and DPC
- 9. WALL TIES : •Wall ties ensure that the wall leafs do not partWall ties ensure that the wall leafs do not part away from each other, effectively splitting theaway from each other, effectively splitting the two leaves. The normal spacing of the ties istwo leaves. The normal spacing of the ties is laid down in the Building Regulations.laid down in the Building Regulations.
- 10. Wall Ties There area large variety of different types of wall ties, but they all have two basic requirements of:- 1 .Tieing the outer and inner leaf of the cavity wall together. 2 .Prevent moisture passing from the outer to the inner skin of brickwork.
- 11. Cavity walls inblock construction
- 12. • The maximumhorizontal spacing of wall ties is 900mm and maximum vertical spacing is 450mm. The wall ties are provided in such a way that they do not carry any moisture from outer leaf to inner leaf. Different shapes of wall ties are shown in below figure.
- 13. Cavity walls inbrick construction with insulation
- 15. • Weep holesare typically found in the outer masonry leaf of cavity walls, just above the flashing with an interval of 1 m. They can also be found above windows, doors or other penetrations. They should be provided at regular intervals so as to allow any moisture collected by cavity trays to escape. • A flashing material in cavity wall construction needs to act as a means to moisture collection, and then more importantly to the diversion of it. Copper flashings exceed synthetics in puncture and tear resistance as well, assuring a stout collection area for any moisture pooling within the wall cavity.
- 16.
- 18. Advantages of Cavitywalls.Advantages of Cavity walls. • The moisture cannot enter from outer wall toThe moisture cannot enter from outer wall to inner wall , since there is no direct contact.inner wall , since there is no direct contact. • Provide good insulation against sound.Provide good insulation against sound. • Protection against efflorescence.Protection against efflorescence. • Proves economical during construction.Proves economical during construction. • Load on the foundation is reduced.Load on the foundation is reduced. • Reduction of heat transfer ,since air layerReduction of heat transfer ,since air layer between leaves acts as non-conductor of heat.between leaves acts as non-conductor of heat.