Cavity Wall Insulation - worth it?

[yeleek]

Hi,

We moved into a new mid terrace 1900's house just before xmas. Its on 4 floors and I don't believe has adequate insulation in the attic room/dormer/walls.

Our gas bill for that first month was huge - 200 quid. Obviously it was xmas we were home a lot and it snowed a lot, however thats a lot to take on the chin every winter.

So wondering what the best options are for insulation pls?

1) Obviously haivng insulation fitted in the attic room would be great, but the extension we are told was added soon after the house was built and directly above the attic are the tiles (i.e. no space to crawl into).

2) Cavity wall insulation - is it worth it? or adviseable in a house such as this? Read lots of horror stories about damp online.

Any advice please?

Thanks

 

[Nige F]

4 floors if it`s got cavity walls - get em filled

 

[yeleek]

Hi,

I believe they are cavity walls, how can I check? Also should I be worried about the horror stories online? People reporting damp and 'blown'? Sorry not a builder type hence idiot questions.

Thanks

 

[Blagard]

I believe they are cavity walls, how can I check?

Hmm! 1900's four floors?

Well measuring the overall thickness of a wall can sometimes give you a guide. However in your case I would drill a hole to find out, better still take out a brick (Drill out the joints).

Personally I would have guessed that it does not have cavity walls due to it's age, but unfortunately I have been wrong on that before and concede the best way is to physically look!

Edit:
Perhaps you could pull out an overflow pipe or waste pipe look and refit, but it could be the builder put loads of mortar back when making good. Still worth considering all the same.

 

[stuart45]

4 storey buildings often started off as 18 inch walls at the bottom and lost half a brick at each floor level untill that got to 9 inch work.

 

[yeleek]

Actually - looked through the vent in the dining room (have a back boiler). And definitely a cavity in the wall. Thinking about it our survey did also mention Cavity Wall ties.... so must have them.

Anything I need to know re best materials? Recommended organizations companies should be part of for the work to be done?

Thanks

 

[Blagard]

What size is the cavity. I ask because you will get gaps between the bricks that may not for this purpose be cavity wall construction.

 

[huw169]

You are right to be concerned. I have a 1930's cavity wall house on the end of a terrace and it can get quite cold. I considered this, however.....
I would urge you to consider all other avenues of reversable work first. Loft insulation, insulation between floors also helps control the heat loss upwards, boiler serviced, ensure the boiler is correctly sized (I have a 4 bed running off a 24Kw), flush your system to ensure all rads are ok, etc.

Once you put cavity wall insualation in you can't get it out! And if it starts to cause damp you are in trouble!
Just for the record - i'm not even considering it as an option anymore.

 

[Nige F]

With due respect to you and the O.P have you a link to the problems encountered on a website or 2. I personally think that the modern rock - or other type of wool fill is fine . Yes , there were problems with wet foam about 30 years ago. But having seen how houses are built from scratch from the mid 60`s onwards, and worked on a few that were put up earlier - I would still say that cavity fill is good.

 

[1john]

I have inhereted cavity wool in my 1950's house, due to water ingress from badly fitted windows (also inhereted) i have found that behind the wood paneling is a nice abount of damp, and upon removing window boards have uncovered a sponge in the cavity.

In a carpenter friends house we had to remove three courses of brick from the bottom of his wall for the entire length of the house and remove all the wet cavity wool as he was getting large damp patches half way up his stairs, the water had got in from a poorly capped cavity where the slates did not cover it properly.

IF, and it's a big if, your house has no way of water getting into the cavity, and you can be 100% sure of it then i suppose cavity wall insulation could be ok. Personally i would never have it installed. There is a cavity, which is left with an air gap, for a reason.

 

[Nige F]

While I am genuinely sorry that you had the hassle with your walls , the reason a cavity is present , in those cases. Is to allow faults to exist and the water to drain away un noticed.

 

[ajrobb]

While I am genuinely sorry that you had the hassle with your walls , the reason a cavity is present , in those cases. Is to allow faults to exist and the water to drain away un noticed.

It is very unlikely that a house built in 1900 with now be without faults. I'd only begin to consider bridging the cavity in an old house with insulation after an independent surveyor says it is OK. Remember, new houses are still built with a void about as big as your existing cavity between the cavity insulation and the outer skin.

Tackle the attic first. If the house also has original windows then don't expect significant savings from cavity insulation.