What's the correct way to plaster walls in a 100 year old mid terraced house?

[Deleted User]

I've got a 4 bed terraced Edwardian house with solid exterior walls. The kitchen is stripped out back to bare brick and concrete floor with the ceiling exposing the floor joists. One brick wall of the kitchen is an exterior wall so what is the correct way to apply plaster to it?
On internal brick walls would it be best to apply plasterboard straight onto the brick or is it best to apply plaster straight to the brick and then skim the plaster when it's dried properly?

A_Lert

Plaster on brick is the traditional approach. But you have a great opportunity to fit internal wall insulation on the exterior wall, if it doesn't already have external insulation. There are a few different approaches, but most will end up with plasterboard over insulation over the wall. (Though there insulating plasters that go directly on the wall.)

neilmcl

Choose your plaster wisely. On solid walls you should be using a lime based plaster.

FreeBear

Ty Mawr (the lime people) do some handy videos on plastering. It isn't particularly difficult.

On a ground floor solid wall, I'd be looking at cork or wood wool insulation with a lime finish over the top. Pay careful attention to where wall units (if any) are going to be fixed, and consider putting sturdy battens up to take the weight.

But I've taken to avoiding wall units as it can make a small kitchen feel cramped and much smaller than it actually is - Some want the extra storage..

edgex

FreeBear said:

Ty Mawr (the lime people) do some handy videos on plastering. It isn't particularly difficult.

On a ground floor solid wall, I'd be looking at cork or wood wool insulation with a lime finish over the top. Pay careful attention to where wall units (if any) are going to be fixed, and consider putting sturdy battens up to take the weight.

But I've taken to avoiding wall units as it can make a small kitchen feel cramped and much smaller than it actually is - Some want the extra storage..

To get anywhere near the u-value required/negotiated with Building Control will mean using very thick insulation if using cork or rockwool.
To get a U~0.5 needs 60mm+ of either on a solid wall.
Modern insulations like PIR can halve that.

FreeBear

edgex said:

To get anywhere near the u-value required/negotiated with Building Control will mean using very thick insulation if using cork or rockwool.
To get a U~0.5 needs 60mm+ of either on a solid wall.
Modern insulations like PIR can halve that.

Whilst materials such as polyurethane foam insulation has a u-value of 0.22 W/m2K, which is much lower than most other insulation materials, it is not breathable. With a solid brick wall, especially at ground level, one needs to avoid trapping moisture within the wall - This can be achieved using a breathable insulation (cork, wood wool, etc), or by leaving an air gap between the wall & insulation.

maisie_cat

Using the incorrect plaster and insulation can lead to damp problems. there is a website www.heritage-house.org that has a huge amount of information and a whole section explaining how cement and gypsum products are not right for old houses.
We are currently removing cement pointing that should have been lime on a stone cottage and removing blown gypsum plaster from the inside and cursing the people whose work we are removing.