Cavity Wall Insulation

Lisa820

I'm thinking about getting cavity wall insulation in my home and was hoping for some advice. It is a 1930s semi, definitely hasn't currently got insulation at present. Where do I start? I've heard some horror stories about the potential for it to cause longer term damage to the property if it isn't done correctly but I don't have enough knowledge of how it needs to be done to ask the right questions of any company I am getting quotes off. Is there any prep work I need to get done such as getting wall ties checked? Any advice on how to confirm if the companies I speak to are reputable would also be appreciated. Thanks in advance.

stuart45

Do any of the walls get a lot of wind driven rain? 
The council always used to clean the wall ties before getting the cavities filled so cavities should be checked for any debris.
The pointing on any facework should be in good condition.

FreeBear

The 1930s was on the cusp of solid wall & cavity wall construction. A lot of houses (certainly around my area) were cavity on the ground floor and solid brick on the upper floor. If your window sills are narrower upstairs compared to downstairs, that would confirm it.

Things to ask -

 1) Will they do a camera survey first ?

        This should pick up on any problems such as a build up of debris in the cavity.

 2) What steps will they take to ensure air bricks remain unblocked ?

       Assuming suspended wooden floors, air bricks often did not have a duct between inner & outer wall. If the air bricks get blocked up, under floor ventilation will be compromised and could result in the timbers rotting.

Have you had new windows fitted recently ?

If not, any guarantee will probably be void as soon as new windows are fitted - You may well need lintels fitted on the outer leaf when you do (but that is a subject for another thread).

I have a similar aged property here (late 1920s build), and to be honest, having cavity wall insulation has made little, if any, difference. It was done under an ECO grant, and the money would have been better spent on plugging draughts and other low cost energy saving measures. I'm now of the opinion that if you are going to insulate, stick wall insulation up. 35mm of PUR/PIR insulated plasterboard on the inside will make a huge difference without the loss of much floor space. If you can stretch to 50-60mm, even better.