Insulation on Timber Frame

[UglyHouse]

We are currently renovating a 1890's timber frame house, and have had a few people talking about insulation and what might be needed.

It is 4"x2" framing, with render to the ourside, and lath and plaster inside.

We are removing all the laths and plaster as we need the timbers to be treated for furniture beetle, so we need to insulate the walls as per regualtions.

I have tried to have a hunt around for any details regarding insulation, but i have found very little to go on.

We are looking at OSB, building paper, then metal lath and then finally render for the outside.

We have been told we will need an air gap on the inside, others have said not. Some have said we will need insulation between timbers, and also on top?

Any advice or to be pointed in the right direction would be cool.

 

[r896neo]

i would get on to one of the major insulation companies for advice, they are amazingly helpful when there is a sale to be had.

 

[UglyHouse]

Good idea!!

Just been so hard to find any info on timber frames, that dont have a cavity!!

Thanks

 

[^woody^]

Typically

Render on proprietary lathing
Air gap (as recommended/governed by metal lathing)
Breather membrane
Sheathing
Timber frame
Vapour check (depends on insulation used)
Plasterboard

Between the frame you could have either 150 quilt or 100mm Celotex/kingspan. However 100mm of kingspan would not allow for services nor pattern staining from the framework, so you would put at least another 30mm of Celotex/kingspan across the internal face before plasterboarding

 

[UglyHouse]

Typically

Render on proprietary lathing
Air gap (as recommended/governed by metal lathing)
Breather membrane
Sheathing
Timber frame
Vapour check (depends on insulation used)
Plasterboard

Between the frame you could have either 150 quilt or 100mm Celotex/kingspan. However 100mm of kingspan would not allow for services nor pattern staining from the framework, so you would put at least another 30mm of Celotex/kingspan across the internal face before plasterboarding

Excellent info, thanks.

Only query is the amount of airgap if i use EML, would the gap left by attaching the EML to the sheathing be enough?
As i thought (in my non experience) that the eml went flat onto the sheathing?

 

[^woody^]

The metal lathing is fixed to vertical timber battens (normally 25mm thick) which give a 25mm air cavity to allow the frame to breathe and any moisture which may get through the render to evaporate.

Check the system manufacturer's recommendations

 

[Zebra579]

Hi,
Aware this is a very old post, but I have a house which is identical to this. It's much older though, around 1700 or so, and the upstairs is a timber frame which originally had lath and plaster on the outside, which has subsequently been replaced with expanded metal and render, attached directly to the frame.

So the timber frame is not able to breathe externally, and there is no air gap as you suggest here.

It was lath and plaster internally, but I have stripped this all off to treat the frame. If I insulate internally, I run the risk of condensation finding its way through to settle on the timber frame. If I create a vapour barrier internally, then any moisture which might get through has nowhere to go!

Any advice would be well appreciated!

 

[^woody^]

Work on the principle of completely filling the frame with insulation, and not leaving, or allowing any air pockets at all for moisture to condense in

Then fit a vapour membrane on the inner face to prevent moisture entering the wall

 

[Zebra579]

Thanks. I don't suppose you would be able to tell me whether leaving the main 6 x 6 ring beam and the roof purlin exposed, thereby creating gaps in my vapour barrier, would be a problem?...
Presumably condensation wouldn't travel through those and into the rest of the frame? Any condensation that got into them would be able to get back out again....

 

[^woody^]

Presumably the barrier will be sealed around the beam and insulation stuffed around it, so the fact that this timber penetrates the wall would not be an issue

 

[chris001]

hi, late onto this thread too, but i am also renovating a house 150 yr old stone walls and slate roof. i have seen lots of stuff about sprayed polyurethene, which supposedly can be sprayed directly onto the tile backs between/around the joists, supposedly stops any condenstion provides hi r rating, minimum density etc. would anyone like to comment, is it that good, or just not advisable, and also how much per m2, this stuff costs, can't seem to find pricing on the internet for this, thanks

 

[Deluks]

No no no no no no no no

Not for a roof anyway. Lots of reasons why, just do a search in the roofing section for 'spray insulation' for opinions on this.

Walls, not so bad, but pricey.