Cavity Wall Insulation

[Graham]

Ok so searching the web has produced the usual list great results and nightmares...so

is there anyone that can give me some real world experiences of having it done..

will it bring my heating bills down or will it destroy my house...


My place is a 4 bed 1930's detached house with double glazing all round and double glazed doors, insulated loft and does a passable impression of an ICE box whilst burning more gas than a couple of powerstations.. so Im looking at all options to bring the cost down whilst warming the place up..

cavity insulation ( yes there is a cavity) looks like an option but Im worried about cold spots and damp, part of me says the cavity is there or a reason...

cheers

G

[Republik]

I'm having mine done on Friday 13th March! The omens aren't good but I'm quite optimistic it will cut down my bills simply because my house at the moment doesn't retain much heat at all.

[mrmaggit]

I'd be surprised if there was much of a cavity, TBH. Our bungalow had it done (injected foam insulation) before we bought it, so I can't say if it improved matters.

The bricks on our bungalow are particularly porous, but as yet, I've not seen any sign of water penetration, and we've been there four years in June.

[jeff m]

If it's an ice box now then your cost/rewards should be benificial.

Insulation is not magic, it will keep heat in but it will not actually produce it

Get an infra red thermometer check the temps around the house inside and out to see if you have any bad spots. Around windows and doors are the places to start.

IR thermometers are also good for checking faulty electric plugs and sticking calipers.

ETA radiators too

Edited by jeff m on Friday 27th February 14:53

[gshughes]

Had it done a few weeks ago on our 1920s Terrace. Combined with beefed up loft insulation it has made a big difference, as we have turned the central heating down approx 50 % and the house is as warm as it was before.

[motco]

My 1930s house with cavity walls (2" was normal in those days and still is IIRC) was done by Cape Insulation using urea formaldehyde foam back in 1980 or 1981 and I have never regretted it. The only problem I has was wasps stealing the foam via an airbrick but a bit of mesh over the airbrick stopped that. I am located in South Bucks - considered to be 'sheltered'. 'Exposed' locations should not use foam but mineral fibre or expanded polystyrene beads, or so it was then. I know the foam is still in place as every time I have to gain access to anywhere that it flowed there's loads of it still. There's no reason to doubt its longevity. No penetrating or rising damp, either.

[motco]

gshughes said:

Had it done a few weeks ago on our 1920s Terrace. Combined with beefed up loft insulation it has made a big difference, as we have turned the central heating down approx 50 % and the house is as warm as it was before.

You're lucky that you house actually had cavities, or at least wide enough cavities at that age. They were new in the twenties and of varying size according to my researches on behalf of my sister in law.

[Huntsman]

Graham said:

Ok so searching the web has produced the usual list great results and nightmares...so

is there anyone that can give me some real world experiences of having it done..

will it bring my heating bills down or will it destroy my house...


My place is a 4 bed 1930's detached house with double glazing all round and double glazed doors, insulated loft and does a passable impression of an ICE box whilst burning more gas than a couple of powerstations.. so Im looking at all options to bring the cost down whilst warming the place up..

cavity insulation ( yes there is a cavity) looks like an option but Im worried about cold spots and damp, part of me says the cavity is there or a reason...

cheers

G

How much roof insulation do you have? I have got some rubbish and plan to put 200mm in this summer ready for next winter.

Do your double glazed windows have slot vents in the tops? Its important when making the inside warmer to ensure you have good ventilation.

[mrmaggit]

Far be it from me to say but nip down to B&Q sharpish.

They have a set amount that they are selling at £1 a pack, while stocks last. British Gas have done a deal with them to waste some more of our money. Once they're gone etc.

[anonymous-user]

If you get it done make sure rooms that have high moisure levels such as kitchen and bathrooms are well ventilated which should reduce any surface condensation.

[motco]

MonkeyMatt said:

If you get it done make sure rooms that have high moisure levels such as kitchen and bathrooms are well ventilated which should reduce any surface condensation.

Cavity insulation will reduce condensation by raising the surface temperature of the inside surface of the inner leaf. Moisture condenses on cold surfaces, why would improving the level of heat retention worsen that? All that said, ventilation is necessary anyway. It's a Catch-22 because you lose heat by venting but if you don't you get moisture problems. The old, now unavailable, Wickes heat-exchanger forced ventilation system is the answer. Remove the moist air via a heat exchanger that cools the air and keeps the heat, and replace that heat into the drier incoming air. Brilliant!

[Deva Link]

motco said:

The old, now unavailable, Wickes heat-exchanger forced ventilation system is the answer. Remove the moist air via a heat exchanger that cools the air and keeps the heat, and replace that heat into the drier incoming air. Brilliant!

That's just mechanical ventilation and heat recovery. Many systems available but Screwfix sell the Vent-Axia one. Takes a bit of installation though. http://www.screwfix.com/prods/52872/Heating-Coolin...

[eldudereno]

We noticed a difference when we got ours done about 10 years ago. If I was in your position though I would make sure that I had at least 400mm of insulation in the loft. I remember seeing one of those 'eco' houses on the tv a while back and they had 600mm of insulation.

[Jaguar steve]

Cavity wall insulation? Huge improvement in heat retention in our 1960s house, the house warms up much quicker too and I'm using a lot less heating oil. Can't find a sigle disadvantage. Go for it.

[rsv gone!]

There is a good chance you'll have too much ventilation. Heating the greater number of air-changes you'll get in an older house will waste you more energy than the fabric loss.

[Pinger23]

http://www.diy.com/diy/jsp/bq/nav/nav.jsp?isSearch...

Have mine booked in for a few weeks time.

[Sgt Bilko]

Pinger23 said:

http://www.diy.com/diy/jsp/bq/nav/nav.jsp?isSearch...

Have mine booked in for a few weeks time.

Is this a good deal?

What type do they use (beads/blown fibre/foam??)

[motco]

Deva Link said:

motco said:

The old, now unavailable, Wickes heat-exchanger forced ventilation system is the answer. Remove the moist air via a heat exchanger that cools the air and keeps the heat, and replace that heat into the drier incoming air. Brilliant!

That's just mechanical ventilation and heat recovery. Many systems available but Screwfix sell the Vent-Axia one. Takes a bit of installation though. http://www.screwfix.com/prods/52872/Heating-Coolin...

Deva Link, Thanks for that link - it's interesting and tempting.

[Deva Link]

motco said:

Deva Link said:

motco said:

The old, now unavailable, Wickes heat-exchanger forced ventilation system is the answer. Remove the moist air via a heat exchanger that cools the air and keeps the heat, and replace that heat into the drier incoming air. Brilliant!

That's just mechanical ventilation and heat recovery. Many systems available but Screwfix sell the Vent-Axia one. Takes a bit of installation though. http://www.screwfix.com/prods/52872/Heating-Coolin...

Deva Link, Thanks for that link - it's interesting and tempting.

The house really needs to be pretty airtight for it to be effective.

[anonymous-user]

motco said:

MonkeyMatt said:

If you get it done make sure rooms that have high moisure levels such as kitchen and bathrooms are well ventilated which should reduce any surface condensation.

Cavity insulation will reduce condensation by raising the surface temperature of the inside surface of the inner leaf. Moisture condenses on cold surfaces, why would improving the level of heat retention worsen that? All that said, ventilation is necessary anyway. It's a Catch-22 because you lose heat by venting but if you don't you get moisture problems. The old, now unavailable, Wickes heat-exchanger forced ventilation system is the answer. Remove the moist air via a heat exchanger that cools the air and keeps the heat, and replace that heat into the drier incoming air. Brilliant!

I was thinking more to stop the condensation on araes that may have a cold bridge. If the average temperature of the rooms increases the warmer moist air (warm air holds more moisture) may condense on these surfaces especialy in the winter.