Is it worth insulating a solid brick front wall?

Blisterman

Completely gutting and refurbishing a Victorian terraced house with a solid front facing brick wall. There's sadly no original internal features remaining, which gives me free reign internally but makes me all the more eager to preserve the front brickwork. I will be adding substantial insulation to all other elements of the house, which leave the front wall as the remaining uninsulated element.

I've had wood fibre breathable insulation priced, and it's come in way too high for our budget. Going for non breathable drylining would be a fraction of the cost.

Of course, the worry is that despite my best attempts at making it airtight, inevitably, there will be some warm air getting behind the drylining and risking mould formation.

So my options, as far as I can see it are:

1. Add enough dry lining to achieve a low U value, and pay special attention to making it as air tight as possible at junctions. And accept the risk of mould. I'm also concerned of damage to bricks, as they're colder and damper than before. I'll admit, I don't really understand this, and how real a worry it is.

2. Don't insulate at all, and accept that this will be a bit of a hole in an otherwise well insulated building. It's a relatively small percentage of the building's overall surface.

3. Add maybe 25mm+12.5mm insulated plasterboard enough to reduce the majority of heat loss and I hope avoid the worst side effects of fully insulating it. Is this a completely flawed reasoning?

Calahonda52

what is the current internal finish on the brick wall?
Any windows?

Blisterman

Currently, there's some crumbling plasterboard, and the plan is to replace the existing PVC windows with timber double glazed sash windows.

booooonzo

can you DIY at all yourself?
check out hemp lime, shuttered on.
it doesnt work out much more expensive than insulated slabs

Ive done wood fiber and it was pricey so going hemp lime now.

hope that helps

Calahonda52

booooonzo wrote: »

can you DIY at all yourself?
check out hemp lime, shuttered on.
it doesnt work out much more expensive than insulated slabs

Ive done wood fiber and it was pricey so going hemp lime now.

hope that helps

Interesting
some links I found reading about it.
.
https://www.bre.co.uk/filelibrary/pdf/projects/low_impact_materials/IP14_11.pdf
.
https://passivehouseplus.ie/articles/retrofit/hemp-lime
.
https://carbon.coop/2019/04/using-hemp-lime-for-natural-insulation/

Shefwedfan

Do it once and do it right, insulated board on all exterior walls. You should be able to do on ceiling as well if Victorian as high ceilings.

I have done two houses. First had no cavity so just insulated slabs. Second had cavity so I pumped it and interior slabs. All ceiling as well as bungalow. It’s a brill job and place is so easy to heat, last house was same. I think it was the 70mm insulation on the slab.

listermint

What sort of pricing were you getting on the wood fiber insulation?

Reason I ask is picked up some recently for a porch conversion and the per meter price was very good.

Let me know what sort of money I may have info

BryanF

Op read the articles by j.Little on ‘breaking the mould’.

Also poly based insulation’s won’t ‘breathe’, you would be best to consider all options before using insulated plasterboard.

‘Calcium silicate’ boards may be a suitable option worth considering

Calahonda52

BryanF wrote: »

Op read the articles by j.Little on ‘breaking the mould’.

Also poly based insulation’s won’t ‘breathe’, you would be best to consider all options before using insulated plasterboard.

‘Calcium silicate’ boards may be a suitable option worth considering

.
.
http://www.josephlittlearchitects.com/articles

Blisterman

listermint wrote: »

What sort of pricing were you getting on the wood fiber insulation?

Reason I ask is picked up some recently for a porch conversion and the per meter price was very good.

Let me know what sort of money I may have info

Between 8 and 10 grand from 3 contractors. The price I'd imagine was mostly the labour since there's several rounds of lime plastering with long drying times.

Was told it would be basically the same price for Calsitherm.

Calahonda52

Blisterman wrote: »

Between 8 and 10 grand from 3 contractors. The price I'd imagine was mostly the labour since there's several rounds of lime plastering with long drying times.

Was told it would be basically the same price for Calsitherm.

Was the lime plastering to make the wall capable of taking the WF or what?

I have used WF in many places and all I ever did was use the proper bonding material, then fitted the WF, with a service cavity outside the WF

Blisterman

The wall was to be lime plastered, then a lime bonding coat, and then a lime plaster finish coat. So it's solid and vapour permeable the whole way through.

listermint

You could use Steico Therm (wood fibre breathable board)
80mm 600x1350mm Board can be got for ~ 20 Euro per Sq M.(ex vat)

The board is fixed to timber or stone using thermal fixings, mesh used on top and lime coat finish on top.


You could have all this done cheaper by sourcing materials and separating out the labour costs. I would not imagine its a large area ? 10K seems alot for the mechanics of it.

booooonzo

listermint wrote: »

You could use Steico Therm (wood fibre breathable board)
80mm 600x1350mm Board can be got for ~ 20 Euro per Sq M.(ex vat)

The board is fixed to timber or stone using thermal fixings, mesh used on top and lime coat finish on top.


You could have all this done cheaper by sourcing materials and separating out the labour costs. I would not imagine its a large area ? 10K seems alot for the mechanics of it.

Is that the flexible board that you dont need to smooth the wall out to fit?
I think i priced it and it was cheaper to lime render the wall flat and buy the rigid boards.

you shouldn't have any gaps between woof fiber and the wall.

This is why im choosing to go shuttered hemp lime now.
removes alot of them awkward problems

check out the links Calahonda52 posted

booooonzo

I should also say the hemp lime as a wet mix is also excellent for sealing up and shaping around the windows , you can apply by hand and let the plaster take care of the finish

listermint

booooonzo wrote: »

Is that the flexible board that you dont need to smooth the wall out to fit?
I think i priced it and it was cheaper to lime render the wall flat and buy the rigid boards.

you shouldn't have any gaps between woof fiber and the wall.

This is why im choosing to go shuttered hemp lime now.
removes alot of them awkward problems

check out the links Calahonda52 posted

No i dont believe its flexible its not rigid as such but not a huge amount of play.