One for the building experts

[Peter T]

My son bought a 1950s semi in May this year, the sort with the rounded bay windows at the front.

Now that the winter is here he has noticed a potential problem. If I look at the construction of the bay windows in the lounge and the front bedroom above there is something strange going on.

The wall under the bay window in the lounge is a standard cavity wall. The wall above the lounge window and up into the bedroom bay is only single skin. This means that, in the bedroom, the wall below the bay window has started to have condensation on it and, already, the new paint is starting to bubble.

I wondered about building a block wall inside the bay in the bedroom to produce a cavity, but there would be nothing below to support it. What about a stud wall with insulation?

Thanks in advance,

 

[Dibs-h]

I'd suggest bonding on insulated plasterboard onto this outside wall - probably the lightest solution in terms of weight\load and it gets the wall insulated for you.

HIH

Dibs

 

[Dee J]

Does condensation on a wall surface make paint bubble? Sounds more like penetrating damp... Does this house have its original windows? If they're plastic replacements then the installation may be faulty and allowing water into the wall.

Dee

 

[wincho84]

I too would look at installing an insulated plasterboard as mentioned above, a product like this

http://www.british-gypsum.com/produ...es/gyproc_thermal/gyproc_thermaline_plus.aspx

would be best as the nature of the product provides a vapour control layrer as well as insulation. The 27mm thick board should provide a decent level of insulation too.

 

[Peter T]

Does condensation on a wall surface make paint bubble? Sounds more like penetrating damp... Does this house have its original windows? If they're plastic replacements then the installation may be faulty and allowing water into the wall.

Dee

Don't think they're original. They are aluminium frame double glazed. Most of the houses in the road seem to have either these or newer UPVC?

The outside of the wall is rendered, pebbledashed and painted and is in good condition. There was no damp there during the summer.

 

[henton49er]

I'd suggest bonding on insulated plasterboard onto this outside wall - probably the lightest solution in terms of weight\load and it gets the wall insulated for you.

HIH

Dibs

+1 for that solution.

 

[Peter T]

Many thanks for the information.

One slight complication! The end wall of the bay is curved!

Would it be OK to cut the board into short strips and bond these to the curved bit to turn it into a multi-sided shape, or is there a better way?

 

[Dibs-h]

Perfectly fine Pete. You might just want to get a can of expanding foam to make sure that there are go gaps, etc.

HIH

Dibs

 

[Peter T]

Perfectly fine Pete. You might just want to get a can of expanding foam to make sure that there are go gaps, etc.

HIH

Dibs

Excelent, thanks for that.

Shopping tomorrow!!

Thanks again,

 

[Dibs-h]

Perfectly fine Pete. You might just want to get a can of expanding foam to make sure that there are go gaps, etc.

HIH

Dibs

Excelent, thanks for that.

Shopping tomorrow!!

Thanks again,

Peter

Go for as thick a board as you can. By this I mean - so as to to make the room too short\small or stick out too much so the window sill looks odd.

Reason for this is that gas\leccy aint going down & you have an external wall - so best fit as thick insulation as you can,

a. afford
b. live with interms of reduction of space.

The stuff comes in sheets with insulation as thick as 100mm. Get the Phenolic insulation - don't get polystyrene. I think you'll want the one that has no foil on the exposed side of the insulation.

HIH

Dibs

 

[Dusty]

Amen to the above and if you do it out of small width sections and still want the curve , you can use Bonding to fill it out over a series of build ups and then skim to finish .

Cheers

 

[Peter T]

Sound advice from everyone.

Dibs - thickness isn't a problem. It's in the bay so the amount of room space lost is miniscule. I'll go for the thickest available boards.

Dusty - sounds like a plan, I'll get me trowel out! I know they like the curved wall, just not sure how much effort they want to go to to replicate it. It may come down to how well the skirting comes off the existing wall. If that can be re-used then it makes sense to curve the wall. If it needs replacing, they may end up with a number of flat sections!!

Many thanks again for your help.