Wall cavity.

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millerman

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Quick question guys, my Son in Law has been told that a cavity wall should be covered in at loft level, ie; the cavity opening should be covered by brick or some form of other covering. I thought a cavity should be allowed to breath at all times. This all stems from a mold issue they have in the lounge and downstairs hallway.
Thanks.
 
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the mold problem is probably due to cavity wall insulation. do you know if it’s been filled?
your son in laws info is incorrect, although the cavity will technically be closed to some degree by felt /membrane/ tile etc.
 
Cavities are always closed or filled with insulation in modern construction for insulation purposes. The practice a long time ago was to ventilate it.
 
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JohnD said:
Where do you think the water is coming from? Wet washing? Steamy shower? Leak?

Find the source and fix it. Insulation does not create water.
Click to expand...
wool cwi creates damp and mold.
who mentioned water? only you.
your making stuff up again.
 
Thanks guys, house was built mid '70s, They are looking to get a grant for cavity wall insulation as none exists at the moment, insulation in loft is about 4inches.
 
millerman said:
Thanks guys, house was built mid '70s, They are looking to get a grant for cavity wall insulation as none exists at the moment, insulation in loft is about 4inches.
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A house of that era should have been constructed with a closed cavity and no insulation.
You need to investigate the cause of the damp before installing cavity insulation. It could be cold bridging due to "snots" in the base of the cavity causing a cold bridge leading to condensation. Lack of ventilation ie trickle vents, extract fans etc or simply not using the available ventilation.
 
Where in the hall and lounge is the mold appearing, close to the floor, the ceiling corners, interior walls, or outside walls.

If its by the floor, on outside walls, it would be worth checking the bottoms of the cavities for built up of detritus bridging the cavity. Usual way to check them is to - remove a single bricks from the outside, in strategic places, then use a light and a mirror to inspect the cavity.
 
Thanks guys, the idea of debris bridging the cavity sounds like a possibility. Mold was at skirting level raising up about 8 - 10 inches, in the hallway it was behind a shoe cupboard, in the lounge/diner it was near patio doors. Cant show you the mold because we have cleaned up the walls with a bleach solution.
 
is no there visible sign of damp?

is the floor concrete?

Are all the damp patches on external walls?

can you photograph the outside of these walls please. Point out the position of the DPC and the gutters and downpipe and the drain or gulley they go into.

thanks
 
JohnD, there is no signs of damp, just mold which is resigned to the outside walls only. Yes, the floors are concrete. I will go visit and obtain pics today. Once again guys, thankyou all for giving your time and opinions.
 
ted456 said:
unhelpful goading removed
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mold is the correct spelling. I suggested the pics.....” warm air moves into a cavity”, causing mold on the internal walls? try and make sense and stop being silly teddybob.
 
Last edited by a moderator:
millerman said:
Thanks guys, the idea of debris bridging the cavity sounds like a possibility. Mold was at skirting level raising up about 8 - 10 inches, in the hallway it was behind a shoe cupboard, in the lounge/diner it was near patio doors. Cant show you the mold because we have cleaned up the walls with a bleach solution.
Click to expand...
have the walls been cavity filled?
 
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