Cavity Wall Insulation

[nic3c]

We are thinking of having cavity wall insulation done. Does it make a noticeable difference? Are there any disadvantages?

[buildersmate]

You will no doubt get a load of polarised opinions.
The purely rational might try and explain that walls, being a large surface area of the total through which heat can escape, will therefore slow the inevitable loss of warmth from the inside to the outside.
However, in terms of cost versus the relative benefit, first make sure you have at least 250mm (and preferably 300+mm) of fibreglass or its equivalent in your loftspace and spend money on draft-proofing properly.
Then consider cavity insulation (before any thoughts about replacement windows and doors - unless they are really old crappy metal framed ones)

[MarzipanQ]

Our house was done when we bought it. All I can say is that if it is effective God knows what the house would be like if it hadn't been done cos it's always cold! I've found more benefit from inproving the loft insulation to the max as described by buildersmate so I'm going with that too.

[keyplus90]

I always agree with buildersmate as he knows what he is talking about and I do not as I am accountant and not a builder. I am seriously thinking to insulate my loft but the problem is that although I do not have arachnophobia but I do not like creepy crawlies and I am sure there are many in my loft. So on good note may be they are keeping it insulated.

[pug100]

I found that this was a handy site to look at before deciding to have it done.

http://www.energysavingtrust.org.uk/Home-impro vements/Home-insulation-glazing/Cavity-wall-in sulation

[buildersmate]

Sorry to have to say this Tony but your answer is incorrect.

1) Cavity walls are not designed like a vacuum flask - they would be sucked empty of air if they were. Cavity walls are designed to prevent the passage of water from the external cavity to the internal - as you partially elude to, before asserting your second error (see 2).
2) Cavity insulation systems (materials plus installation) have to be approved - normally by the Agrement Board - to ensure that your second incorrect assertion does not happen. Provided the system is approved, no passage of water will occur. This is normally assured through the use of cellular foam - closed cells of gas, through which water has no passage. The installer has to undertake a site inspection prior to installion to check the exposue of each wall - in certain exposed locations, the property is not suitable for cavity filling.

[rov1200]

Sometimes I think mice are using the filled cavity as a breeding ground. Maybe the fibre glass does not cause irritation to them.

[nic3c]

Hmm, thanks. The more i read about it the more it puts me off.

keyplus90 - try buying a big plastic creepy crawlie/spider and put it around your house. You soon get used to it and then the normal sized ones aren't so bad any more.

[droopdrawers]

All I know is we had it in the last house we bought and by god we were a whole lot warmer in there than we are here.

This property is leasehold and a flat so we have to wait til everyone else wants it done.

Apparently now there is such a long waiting list it probablt won''t get sorted this winter now.

Bit my opinion is yes have it installed asap.

DD

[alishalexy]

Just had my home done, the walls where filled with these polystyne balls. I can't notice any difference. They advised us to take all pictures off walls and the window sills. Apparantly your walls shake for the 1 to 2 hours they are there. I only noticed next doors shake a little.
If you have any holes anywhere inside then a few balls will get through. They say it saves on bills if you get the loft insulated.