[Closed] Cavity Wall Insulation

Most definitely: Although the new blocks, methods of construction, i.e. air tightness etc, do help improve the energy efficiency of houses, insulation still makes the most difference.

mmm think we might get it done then as it seems pretty cheap.

Bloody horrible stuff

I had a house done and in the kitchen I [b]always [/b]had cool beer in a cupboard until the cavity walls were done 😥

I had to use the fridge afterwards

guess it worked and the house was alot warmer

So is £125 for a 4 bed house an okay price?

That's an absolute steal. It must be grant funded too.

I had a 3 bed bungalow done 10 years ago and it cost £350 iirc

so £125

YES

Just phoned the surveyor, he'll be here at 11:30. Price is now reduced to £90. And yes it is part funded by a grant system.

A 10 year old house with no cavity wall insulation? Can this be right?

Does cavity Wall insulation come as standard?

Contact the energy efficiency people, 0800 512012 they'll sort you out with contractor and it's rockwool insulation they fire into the cavity, not the dodgy chemical stuff of a few years ago. I'm waiting for mine to be done b4 Xmas, under £200! Toastie 🙂

Surveyor has just left, yes they use rockwool and yes it does cost only £90. Cosy winter here we come.

Sounds tempting...certainly came up as a recommendation on our survey when we bought in August. Are there not issues with increasing the possibility of damp problems when you fill the cavity (what is there to stop damp etc?)

Just be very careful about what they are about to stuff in your cavity ( 🙄 ). It is unsual for a house of that age not to have cavity insulation, if it doesn't there may be a good reason.

Our house is 8 years old and has no cavity insulation. This is because the bricks they used are very porous resulting in a lot of water running down inside the cavity (which is not a problem if it can drain out the bottom). To ensure our houses still complied with the insulation requirements the builders used the thermalite style blocks rather than standard breeze blocks. On the next phase of our estate they changed the bricks to a denser brick and then used normal breeze blocks but installed panel insulation in the cavity. What ever they put in needs to maintain the waterproof barrier the air gap provides, if it doesn't you'll have big problems with damp crossing the cavity and your internal walls will bet wet.

We're in the process of looking into having it done because there are products on the market that will prevent the water crossing over. It's worth specifically asking the question about how the insulations works.

Get it wrong and this could be you

[img] [/img]

Full article [url= http://www.askjeff.co.uk/cavity.html ]here[/url].

Eek, I've just read the artcile properly myself. I live high up on the hills in Lancashire and we get a lot of wind driven rain. May garage is amde from the same bricks as the house and I know the water penetrates them. If you put your hand flat on the inside of the wall in a storm there is so much water runninf down the wall it will run over your hand. I waterproofed the garage by lining it with polythene damp proof sheets.

Not so sure I am going to do it after all.

[i]Are there not issues with increasing the possibility of damp problems when you fill the cavity[/i]

There were damp problems with the old stuff they used, foam, but rockwool lets the house breath. And yes it does get round the energy efficiency issue in home reports.

[i]Cosy winter here we come[/i]

But in the summer its like an Oven!

I live in the west of Scotland, it is highly unlikely the house will ever feel 'like an oven'. If this should ever happen I will let air in by opening windows.

Basically full-fill insulation is not that suitable in very exposed locations, particularly if you have recessed pointing to the brickwork.

Cosy winter here we come

But in the summer its like an Oven!

Actually it should result in a more even temperature being maintained.

i was under the impression that loft insulation was far more effective than cavity wall insulation? given the level of bother involved why not go over the top in the loft and allow the house to breath as it was built to?

Loft has been checked and it has correct level of insulation.

If you live in extream exposed areas full fill cavities is a no no, (take a look at the NHBC's map for exposure areas) and as mentioned even worse with recessed joints.

We tend to stay away from full fill cavities on new builds now and maintain a full 50mm clear cavity, to be honest as long as the cavity isnt bridged, you have cavity trays in the right places and weep holes for any moisture (wind driven rain) that WILL get driven through the outer skin and into the cavity to escape there shouldnt be a problem.

I find it odd that a house only 8 years old doesnt have any cavity insulation, even if Thermalite blocks were used should still have been insulated.

Well I don't live in an exposed location and the house is 10 years old. We won't be staying here for ever and as long as I get a few cosy winters and an energy efficiency certificate I'll be happy.

I find it odd as well that the house doesn't already have cavity insulation.

The problem with partial fill insulation is keeping the cavity clear of mortar during the build, which contractors are notoriously bad at doing - we have even made contractors remove insulation and clean the mortar out before they will get paid.

Actually Rockwool blown cavity insulation has been approved for use in exposed areas because of it's resistance to weather and ground moisture. Not only is it water repellant, it is also breathable. Normal Rockwool full-fill is not suitable for exposed areas but the blown stuff is.

I know my house hasn't got any cavity insulation because I watched it being built. I actually questionned the building inspector about it when he was on site one day when we were there. A couple of houses on our street did have immediate problems with penetrating damp - cause mortar bridging the cavity, they had to chop out the outer bricks to clear it.

Also had a chat with one of our structural guys at work and what he said also makes a lot of sense. One of the best insulators short of a vacuum is air. The only thing the cavity insulation does is stop it from circulating. As long as you don't have excessive air movement in your cavities you won't see much gain from the insulation. I've done a 180 since this morning and am definitely not going to put it in. Instead I'm going to add additional insulation in the loft as it is only 100mm deep and I believe the recommended level has now changed to 300mm deep.

I pulled out of the sale of a house because of the surveyor's report. He was dead against it. Future rot problem.

Best method of insulation is to insulate the wall externally.
No issues of interstitial condensation as the whole wall structure beneath the insulation is kept warm,so no cold briging either.
The drawback is that it is expensive compared to cavity wall when used in a retro fit situation,but is worth considering if your walls are in poor condition or you other were going to render your house anyway.

Many modern buildings do away with the cavity altogther and use aircrete with external insulation.
Wih this method and the right specification of insulation,it is possible to have a house so well insulated that,little or no heating is required,what is known as a passive house.

Ground source heat pumps and solar energy can be used to genrate what little heat is required.

silver bonded bead is the best

no transmision of water

better fill

better ir reflection

finding an installer is difficult, but you can get grant assistance