Insulating a solid wall in a 250yr old house....

[Matthew]

Hi,

In few months we move into a house build in about 1750.

As such it has no cavity or any insulation to speak of!

We're planning to dryline the walls and add some insulation - cellotex or kingspan etc.

Does anyone have any information - or weblinks - on the following....

1) Comparative U values for cellotex v. kingspan etc etc.

2) Comparison of a 9" solid wall v a modern cavity with CWI - just so I have some idea of what can be achieved, compared to the modern house we are in now?

We need about 80 8ft by 4ft sheets of whatever I select!

The problem I have is that due to the room design, on some walls I can only put a thin insulating layer (plus plasterboard etc.) without having to move doorframes! Hence finding the best for the job?

Do any of these insulating systems allow for easier affixing of the plasterboard panels? Can you dab and dot onto them direct? Are some easier to install than others?

I need as much reduction in heat loss as possible, so I can get the boiler sizing right. Seen a lot of mention of the myson boiler sizer, but can't find it on their site? Any ideas?

Any help and advice greatly appreciated!

Many thanks

Matthew

[Phil L]

Is the house bare brick or is it rendered / textured outside?

If not, how would you feel about having it rendered / textured outside?

Insulation doesn't have to go inside, it can be affixed to the exterior walls, then a 'mesh' goes over it and finally it's finished with a textured coating (not render, it's a sort of polymer resin which doesn't crack) in a choice of finishes....it would also probably be cheaper, easier and quicker to do it this way rather than upset every room in the house....there's some good information here at the Energy Saving Trust's website: (acrobat reader required)

[Chris Bacon]

Did you post a similar question some time ago? Maybe a year ago?

This presumably means that you will have to completely gut the place. Are alterations subject to any restrictions, e.g. is it listed, in a conservation area, or anything similar?

Google will find that lot easily.

Can you explain that a bit more?

A question, or a statement?

What about external insulation? Possible? Do you really have to add insulation on the walls? It's possible that you may create problems fiddling about with an old place like this.

[Matthew]

'Fraid we can't touch the external render - its Grade II listed and the listing includes some of the external brickwork detail. If it didn't I'd go down that route!

Thanks

Matthew

[Matthew]

Wasn't me - we only saw the building for the first time in March this year.

Grade II listed - so we can't change anything external, but the Conservation Officer didn't have any objections to adding insulation in this way... Agreed about the gutting. The house hasn't been touched for about 60yrs - apart from adding an immersion heater and rewiring. All the windows and sills need placing, and central heating added - so its all pretty major stuff any way!

Will try again!

I'll try. The doorways in some of the rooms are right in the corner of the room so the there is no (or little) gap between the adjoining wall and the doorframe. In our current house all the doorframes are inset about 150mm from the corner of the room - in the house we are moving to there isn't this gap - there maybe 50mm max.

A statement. If I've only got a total gap of 50mm, and I need about 20 of that for plaster and board, I can only have about 25mm of insulation. So I need the most effective 25mm of insulation I can get!

I think my only option is internal, as the listing specifies some of the external brick work detail, which would be lost if it was external insulated. Using internal means I can also hide some of the hideous rewiring (well our electrician can) and run pipework runs out of site. The floors (on all levels) are solid so there is nowhere else to conceal pipework.

Thanks for taking the time to reply,

Matthew

[PeTe33]

Doesn't Grade II also include internal "features" too ?

[Hugo Nebula]

On 22 May 2006 11:38:34 -0700, a particular chimpanzee named "Matthew" randomly hit the keyboard and produced:

AFAIK the same stuff (if not, then virtually the same). Conductivity of 0.023W/mK.

A 9" brick wall with dense plaster internally = 2.0-2.1W/m²K. The Building Regulations require a U-value of 0.35W/m²K for new walls. It has been coming down from 0.6W/m²K in 1990.

Why go to the bother of insulating the walls to such a great extent? There are other ways of reducing the heat losses for much less hassle. Insulate the loft. If you have timber ground floors, put insulation between the joists. Even if you can't replace the windows due to it being listed, you can fit draught seals.

[Dave Liquorice]

Look at the respective websites. But to be honest both cellotex and kingspan are the same type of ridged foam so the insulation values are going to be fairly similar for a given thickness. ISTR that these types of product give the best insulation per unit thickness of anything.

Only 9"? Bit of a wimpy 1750's house? Ours are about 18" thick but rubble stone, not a brick in sight. Compared to a modern wall with CWI solid walls loose heat like it's going out of fashion but they do store a lot of heat (or cold). So I'd only insulate the exterior walls and let the interior ones regulate the house temperature, keep it cool in summer and warm in winter (just don't switch of the heating or it'll take days to warm back up, BTDTGTTS).

You can get cellotex/kingspan ready bonded to plaster board. Just fix 1" thick battens to the wall attach panels to battens. Used some 25mm insulation + 9mm or so plasterboard on the end exterior wall of a small bedroom here. Made *very* noticeable difference to the room (just two sheets).

[Ian Stirling]

This improves things a fair bit. But, the walls on most houses without insulation are a really, really large source of heat loss.

[Dave]

Doesn't that infringe your human rights of freedom of choice, or does that only apply to criminals :-(

Dave

in argumentative mode :-)

[The Natural Philosopher]

Practically the same.

Both are infinitely more conductive than whatever you will line them with.

Ouch. won't be cheap..

Mm. new doorframes?

I wouldn't bother. Stud the inside and wedge the panels in and nail the board on.

Or accept cold spouts where you gouge for cable runs..

Never mind the boiler sizing, its the overall comfort factor ypou will notice..

[Matthew]

Certain ones - but the CO said its OK. We'll still need to apply for LBC though...

Cheers

Matthew

[The Natural Philosopher]

Friends of mine did this to a grade II years ago. Essentially built a new house inside the old one. Out of block. Cavity insulation between.

Lovely deep window sills.

Bite the bullet and make up new frames.

Try and go deeper. but otherwise celotex/kingspan is as good as it gets IIRC.

If you use 15mm of board only, thats 35mm of kingspan.

[The Natural Philosopher]

Largest heat loss in total is through roof for sure (after draughty doors windows and floorboards), but one assumes the OP knows this, has a plan, and doesn't need to ask.

Second is the walls..by virtue of their area and exposure.

Then the ground floor.

And finally windows..

[Dave Liquorice]

The 100 fold difference in conductivity? Lets be simple, think of a hous= e as a 10m x 10m x 6m high box. That gives us four walls of 60m^2 each or = a total surface area of 240m^2. 20k temp differece, solid wall =3D 9600W loss, insulated wall 96W loss. Very simplistic but illustrative, want to= run a 10kW boiler flat out or just have some ordinary tungsten lights on?...

[Peter Crosland]

Listing does not only apply to the exterior. May sure the CO confirms it is OK in writing to be on the safe side.

Peter Crosland

[Matthew]

Sure will! We have a large list of items we need written confirmation of!

Cheers

Matthew

[Christian McArdle]

You can get insulation board with plasterboard ready attached. On walls with the door frame problem, use the thickest you can get away with. I would tape and fill these boards, rather than skim to get a bit of extra depth. These boards will be special order only, don't expect to go down a builder's merchant and drive away with them!

As for specific brands, Kingspan Kooltherm K17 is suitable for adhesive bonding. Kingspan Kooltherm K18 is only suitable for battens, metal furrings or mechanical fixing. Adhesive is probably easier when you have limited space, but allow a few mm for the adhesive. Mechanical fixing could also work.

Unfortunately, 47.5mm is missing as an option for K17 (but would work with K18 mechanically fixed). If you can't accommodate 52.5 and want K17, you would need 42.5mm, which is only 30mm insulation. This still provides around

0.5 uValue, which is a very worthwhile improvement, both in terms of comfort and efficiency. For the other walls, where space is not such a premium, the thickest available K17 is 97.5mm total (85mm insulation) provides a uValue of 0.20, which is very good indeed.

Christian.

[Dave Liquorice]

My local one does, at least in 25mm insulation thickness...

I'd be a little cagey about dab and dot onto an ancient solid wall.

Penetrating damp might appear behind the dry lining once you restrict the ventilation right down and, unless your taking floors out and sealing round joist ends, condensation from warm moist air leaking from the rooms to behind the insulation is also distinct possibilty.

[Christian McArdle]

Yes, the 25mm (37.5mm) boards are specified for ceiling insulation when additional has been put between rafters, so could well be a stock item. However, these are likely to be K18 or equivalent, which doesn't specify adhesive or dot'n'dab as installation methods.

Yes, it will certainly not be as good as a method using some sort of cavity either within or inside the wall. However, with only 50mm to play with, it is simply not possible to specify one. The Kingspan/Celotex itself won't care about moisture. However, you might want to consider sealing the gap between boards to avoid moisture attacking the plasterboard or joint from behind.

Christian.