Solid external wall advice

[Russ P]

After some advice/guidance I have stripped a late 1800’s cottage back to brick and currently boarding it. Is there any method to dab a vapour board to the external walls? I was always under the understanding they had to be hardwalled or batten and boarded (not keen on this method as don’t want to loose depth) but was told by someone a few days ago I could dab vapourboard

[scottishjohn]

I think the answer is yes.

you could fasten  25mm or 50mm  batons direct to bricks --so loosing  only an inch or two  and be able to put a VCL in,which  is the way I would go 

 

but firstly  are you really  sure there are no damp problems,you need to check carefully ,

if there are these need to be sorted first ..

I,m guessing its not a cavity wall  and originally it would be lime mortar 

if it has been pointed with cement mix then that could be a problem  waiting to happen ,cos cement does not breath and is not flexible like lime mortar ,so any cracks in pointing and water runs in  and don,t come out.

with the change from lime to cement was when they went to cavity walls 

so any moisture in the wall cannot evaporate outwards 

only inwards  . 

Yes you could paint or render

.maybe ,if you have the money its time  to insulate it on outside .then render  or brick slips--2 jobs at once! warm +dry

 

 

Edited May 8, 2019 by scottishjohn

[nod]

36 minutes ago, Russ P said:

After some advice/guidance I have stripped a late 1800’s cottage back to brick and currently boarding it. Is there any method to dab a vapour board to the external walls? I was always under the understanding they had to be hardwalled or batten and boarded (not keen on this method as don’t want to loose depth) but was told by someone a few days ago I could dab vapourboard

You can dab a moister board on 

Or even a foam backed board

 No need to machanocal fix if it is bare brick or block 

[ADLIan]

Foam (insulation) backed plasterboard must be mech fixed to wall (otherwise it’ll just fall off in a fire!)

[nod]

13 minutes ago, ADLIan said:

Foam (insulation) backed plasterboard must be mech fixed to wall (otherwise it’ll just fall off in a fire!)

No

Ive fixed thousands of them 

No problem at all 

Dab with standard drywall 

[ADLIan]

Suggest you check MIs and BBA certs re additional mech fixings when using adhesive or plaster dabs with foam backed boards

[Russ P]

9 hours ago, scottishjohn said:

I think the answer is yes.

you could fasten  25mm or 50mm  batons direct to bricks --so loosing  only an inch or two  and be able to put a VCL in,which  is the way I would go 

 

but firstly  are you really  sure there are no damp problems,you need to check carefully ,

if there are these need to be sorted first ..

I,m guessing its not a cavity wall  and originally it would be lime mortar 

if it has been pointed with cement mix then that could be a problem  waiting to happen ,cos cement does not breath and is not flexible like lime mortar ,so any cracks in pointing and water runs in  and don,t come out.

with the change from lime to cement was when they went to cavity walls 

so any moisture in the wall cannot evaporate outwards 

only inwards  . 

Yes you could paint or render

.maybe ,if you have the money its time  to insulate it on outside .then render  or brick slips--2 jobs at once! warm +dry

 

 

I was hoping to avoid batten and board as the 2 of the rooms are small already. The outside is already rendered and painted and I’ve not had damp issues in the 3 years I’ve owned it so far. 

I was told it was the standard foil backed plaster board that can be dabbed 

[Russ P]

9 hours ago, nod said:

You can dab a moister board on 

Or even a foam backed board

 No need to machanocal fix if it is bare brick or block 

Is there’s a certain adhesive you have to use for the vapour boards (foil backed)?

trying to stay away from foam backed due to the rooms being small already

[Onoff]

See the application sheet here. Says to put foil backed GA4000 boards up then over  batten i.e mechanically fix.

 

But for the PL4000 it shows for and dab.

 

https://www.celotex.co.uk/applications/wall-insulation/internal-solid-walls

 

One benefit with over battening is that you can design in a nice service cavity for wiring.

[Ferdinand]

To save depth you could use roofing laths as your framing timber.

 

For me the key dimension would be how much insulation it needs.

 

F