another insulation question

[Ron]

Hi I have been doing research on insulation and was wonderimg why new houses were not built with cavity wall insulation. I live on an estate that was built in 1991-1993 or thereabouts and none of the houses have cavity wall insulation. Was this just because the houses were built to keep the cost down or is there a reason why there is no cavity wall insulation as standard?

I will be 60 in a years time and have also discovered that because of this I will be entitled to discounts if I upgrade my loft insulation and install cavity wall insulation so I will wait another year before doing this.

I filled out an online survey and according to it I would only save £12 a year with cavity wall insulation. Perhaps this is the reason it was not done as standard? Not cost effective enough?

Thanks Ron

[RedOnRed]

You don't have to be 60 to get a discount. We've had both our wall cavities and loft insulated this year subsidised by grants and have paid next to nothing.

Try these people...

[kevin foote]

Ron,

I think you answered your own question.

Kev

[Bob Watkinson]

Ok my dumb question of the year. How can you tell if you have cavity inulation and how do you know if you have a cavity or not?

[Ron]

I watched the houses being built and asked about cavity insulation. Not necessary I was told as the walls are breezeblock with foam backed plasterboard (which gives the equivalent of cavity wall insulation) stuck to the breezeblock then a single layer of bricks built about 4 inches away. I thought all recently built houses had cavity walls, i.e. breezeblock space then bricks.

Cheap built L&C houses. I wonder why they went bust? I remember one of the workmen telling me that selling one house paid for 4 being built. I think he was having me on, I would have said 6. All of the above has been my recollections from 15 years ago, I have been looking at ways to save money on my gas and electric bills as my pension will not be as much as I thought/hoped it would be and I want to get any major spending done in the next 5 years while I am still earning.

Ron

[MarkK]

See if you can see the top of the walls in the loft. If you have insulation it should be evident - white foam bulging from the cavity in places. Wall thickness is a good indication of whether it has a cavity. Measure some bricks and do some arithmetic.

Mark

[Peter Taylor]

Ron, back in 91/93 the standard of thermal insulation required by the Building Regulations was much lower than it is today. I think it was still possible then to achieve the required standard for walls without needing any extra insulation at all, just by using aerated concrete blocks for the inner skin. But there were various other ways of complying with the Regs and probably the reason your builder chose to use foam-backed plasterboard was because he could use cheaper concrete blocks and he didn't need to use wet plastering, which made the construction much quicker and cheaper for him. It also has the advantage of retaining the full width cavity, which reduces the chances of any dampness penetration due to cavity-bridging.

£12 a year does sound a bit low maybe, but I'm not surprised. If the walls already have a relatively high U value, extra cavity insulation will not make a major difference to the heat loss. It could easily take 20 years or more just to save the amount of energy used to manufacture the insulation and transport it to your house, and so I think you'd be sensible to ask yourself if it's really worth doing.

Peter

[Alan]

I fitted Cavity Wall insulation to make the house more comfortable, rather than to reduce my bills. If you feel the house gets cold soon after turning off the heating, or if the heating appears to be fighting against the cold coming in from the walls (esp in a hall/stair next to an external wall) then you would benefit from a comfort level by having it fitted.

There are measurements you can do with the wall around external doorways/windows, but the only sure way would be to drill a hole through the wall and check the gap if there is one(which is what the fitter will do prior to coming out to install the insulation.)

[Hugo Nebula]

On Sun, 02 Oct 2005 21:29:50 GMT, a particular chimpanzee named "Ron" randomly hit the keyboard and produced:

It sounds like the insulation-backed blocks that were common in the early 1990s. Theoretically, the amount of insulation on the back of the block was equivalent to that required in the cavity, and gave the same U-value.

Their advantages were the they maintained a clear cavity in addition to the insulation, and they were quicker and easier to build with. Their disadvantages were that the gaps between the insulation would reduce the effectiveness of the insulation, and often builders wouldn't use long enough wall ties to take account of the additional structural cavity width.

They fell out of favour with the change to the way U-values were calculated in 1995, which required the cold bridging of the gaps between the insulation to be taken into account. Having said that, the difference between the U-value (0.45W/m²K) claimed at the time and the U-value by the 'new' way of calculating it is probably no more than 0.1W/m²K, and certainly better than the insulation standards of houses built 10 years before. One would probably get a better return on your money by increasing the insulation in the loft and better heating controls first.

[The Natural Philosopher]

Odd. After teh roof, teh walls have the geratest surface area and teh maxium potential heat loss.

I'd sayt that most double glazing was a complete waste of money, but not cavity wall insulation.

[Dave Fawthrop]

| Odd. After teh roof, teh walls have the geratest surface area and teh | maxium potential heat loss. | | I'd sayt that most double glazing was a complete waste of money, but not | cavity wall insulation.

If your walls and roof have been insulated, double glazing is well worth while. Particularly because you get neoprene seals thrown in, which beats DIY draghtproofing hands down. Also, in our case, the wooden windows were rotten :-(

[Rick]

When I insulated my self build I spent an age with the maths working out how long it would take to get investment back. Insulation has a much bettwer return than the 12 quid, unless you don't heat your house much anyway.

Rick