Cavity wall insulation grants

[mpooley]

I have a strange situation where i find 2 of my internal walls are in fact cavity walls !
I cant just fill over the tops as they go right up to the roof tiles.
Oh BTW  it is NOT part of an extension it was all built at the same time.

So I have had one company say no grant is available as they have to fill at least 70% of my cavity to get the grant at a cost of £285.00 and another say it doesn't matter and that i will get a fixed charge of £149.00  ! and that is including a grant.

the first guy reckons that the other company is just ripping off the govt grant scheme by lying about the work they are doing but he wont do that.
Fair enough but is he right?

anybody know?

thanks

Mike

[Other-Power]

why insulate internal walls?

[mpooley]

Because they go straight up into the loft and up to the tiles in other words they are acting as external walls by being full of air at external temperatures
IYSWIM

mike

[Other-Power]

insulating the cavity will not stop the thermal bridge that these walls are offering as the heat will be transmited by the brick in the wall construction.

You would need to externaly insulate these walls to stop them transmitting heat up into the loft.

Cheers

Jon

[Baz]

Filling the cavity will stop them acting as a chimney taking heat up and away. Insulating internal walls allows sections of the house to be heated alone more efficiently.

[biff]

if you had stuffed the top of each wall with the foil wrapped sausages you would have seen a massive improvement by now,it should only take less than 30mins,use a length of 2x1 batton to push them into the places you find hard to reach by hand.
                                                                                                       biff

[mpooley]

insulating the cavity will not stop the thermal bridge that these walls are offering as the heat will be transmited by the brick in the wall construction.

You would need to externaly insulate these walls to stop them transmitting heat up into the loft.

Cheers

Jon

I do see that but as Baz states the cavity  is acting like a chimney at the moment shifting quite large amounts of heat I imagine.

I don't believe the heat traveling up through the blocks will be significant but am intending to insulate the walls in the loft if I can.


"f you had stuffed the top of each wall with the foil wrapped sausages you would have seen a massive improvement by now,it should only take less than 30mins,use a length of 2x1 batton to push them into the places you find hard to reach by hand."

Biff I would have loved it if I could do this. I spent a long time in the loft trying to work out how to do it but it was impossible . The access was far too limited. It would basically have meant removing 1 half of the wall and replacing it afterwards.

Mike

[rogeriko]

If you drill a row of holes about a foot apart up in the attic you could squirt in the cans of expanding foam that would block the cavity and stop air rising.

[mpooley]

If you drill a row of holes about a foot apart up in the attic you could squirt in the cans of expanding foam that would block the cavity and stop air rising.

Actually that's quite a good Idea 
although still extremely difficult to do right down in the eaves.
Also the cavity is 70mm. I reckon i would be lucky if the foam didn't just drop down the hole.
I reckon a hole every 2 to 4 inches would be needed. worth experimenting with though !  thanks

[rogeriko]

Put a longer tube on the can so you can push it all the way across the gap and then slowly pull it back then the foam will stick on the other side first. Put a few bricks together in the garden first to practice and you will see how big the foam gets after it has finished expanding with say a 5 second squirt.

[Baz]

Can you get to each end of the wall, the actual end face, and make a big hole like 2 bricks. Then get a string through to pull through Biff's sausage.

[biff]

 no offence , but i cannot help but smile.
                 when we brickies first came in in contact with sausages(soundproofing old peoples homes in borough green) we sneered at the very thought of this whacky idea,especially when we had to chase after them on a windy day. but they became the norm and if anyone was foolish enough to forget them or leave them out,they got their marching orders,so sausages do work.
 to insert sausages across a wall which you do not have access is simple enough,
   you find the course which is just above the tie wires and drill out a brick every 1200mm along the course,when you are stuffing in the sausages you send one half to the right and one to the left,after you do a few you will soon get the hang of it. you feed a bit of plastic pipe through from one hole to another,attach the end of the sausage to the pipe and gently draw the sausage back,,it will move better on it edge
 then you can turn it on its flat on top of the ties,the snots on the back of the brickwork help to keep it up in place,
   it was always considered an ar$e of a job but the money charged for such work is astronomical,there were various handy ways of doing it but mostly we reverted to the above.i do not know any other item in the building trade which has had so many jokes and smart remarks made about it and still remains one of the most underated.
                                            biff

[martin W]

Ok where or what are the sausages??? google doenst come up with anything

[biff]

simple lengths of fibreglass insulation, some,,,,,12..mm long 150 wide by 100mm,,,,wrapped in perforated foil or clear plastic and used to stop sound travelling from one flat to another or used to stop the transfer of heat or warm air,,,, hence the use in old peoples homes.
   they are placed verticle in the cavity during construction,, brickies used to loath them,, but,,, but  we learn,
                                                                                          biff

[AndySussex]

What is the advantage to those over just using normal insulation - rockwool/celotex etc?