Wall cavity

[Chippygeoff]

I recently had all the old rockwall type cavity insulation removed as it was all soaking wet and The internal walls were getting wet as well. Once the leak on the roof has been fixed I will have polystyrene ball insulation put in. Would anyone have any idea how long it will take for the cavity to dry out. Many thanks in advance.

 

[RobinBHM]

I dont know the answer, but I read this article when looking into cavity wall insulation

http://www.askjeff.co.uk/cavity-wall-fill/

Was the rockwall wet from your roof leak or from rainwater getting through the extrrnal skin of masonry. Is it brick facework outside?

 

[Phil Pascoe]

I can't help on that - but if you have to have holes drilled (which I would think you have to) - why not ask the firm that's going to do the job to come and drill the holes? At least you would have some ventilation for a while - a few weeks in warm, dry weather with ventilation will dry a lot.

 

[Phil Pascoe]

My father was a builder (quite large scale - when he sold his half of the firm in 1973 they were holding 800 acres of first class land with building permission) he used to go absolutely nuts if someone suggested having cavities filled. I read now that the RICS don't recommend PU cavity insulation where there is adverse weather and driven rain (that counts out most of Cornwall, for one :lol: ).

 

[Cordy]

Geoff
Filling cavity walls might not be a good idea
We don't have very cold winters

In summer correctly filled walls will keep the heat in; hindering good ventilation
To have walls filled they must have had the initial brick-work done to a high standard

Poorly fitted brick ties and mortar dropping down the cavity are a prime cause for concern and not easily detected

 

[Phil Pascoe]

On our EPC it said we should get cavity insulation, not noticing we already had it ... they didn't notice 24 feet of single skin 4" block wall between the bungalow and the garage ...

 

[Lons]

As said, poor quality bricklaying is the main problem as on most of the big sites the brickies are subbed or on peacework and cavity bridging especially across wall ties was very common. Retro fitted insulation doesn't stop the bridging and can exacerbate it .

In later buildings with built in full or partial insulation such as cavity bats, the mortar dropping problem is largely eliminated as the in situ bats prevent them dropping down the cavity and bridging.

Our house was built in the early eighties and cavities filled with loose polystyrene beads and we've had no problems with bridging even though the house is exposed. The biggest problem with loose beads comes when you drill holes or remove bricks when the bl**dy things escape and fly all over the place. :lol:

Bob

 

[sunnybob]

I had rockwool insulation fitted into my house way back in the late 70's. It did a magnificent job keeping that place warm. It was on top of a big hill with howling winds, and all I had for heating was a single gas fire in the through lounge and a single flame gas hall heater on the upstairs landing. I had it fitted to my next house in the mid nineties. Same results.
I spent a lot of time comparing efficiencies. Rockwool came out tops every single time by a long way. If that house was mine, I'd put rockwool back in.

 

[morturn]

I find brickwork tends to dry out quite slowly, I had some that took over a year, although it was a 9” solid wall.

You may get efflorescence after it is dry, so it still looks damp and will damage paintwork