Can I tongue and groove an external stone wall?

[Weetabix]

Hi,

I'd like to tongue and groove our kitchen, but am wondering if there would be an issue with build-up of condensation behind the timber causing it to warp/go mouldy.
The walls in question are solid stone walls - all exterior - and all lime plaster has been removed/fell off, so the stone is bare.

I've read in a few places that there shouldn't be gaps between walls and cladding, but worried that if there isn't a gap, the moisture created on the stone when it's cold will have nowhere to go?

Any ideas?
Thanks.

 

[a twig]

There’s a slightly amusing thread here about wainscoting which in between the commenters slightly losing the plot details what a few of us have done.

Wainscotting to manage damp?

Our home is a generic North London 2 bed Victorian end terrace with little in the way of original features. We have quite bad damp at the base of the party wall which I think is due to a combination of the ground being clay, a concrete floor in the kitchen pushing damp up the walls, and modern...

www.periodproperty.co.uk

For the most part, battening off the walls and venting top and bottom seemed to be the trick

 

[Weetabix]

Great thread, great advice - and yes - slightly amusing! Thanks @a twig!

 

[Toby Newell]

Hi,

I'd like to tongue and groove our kitchen, but am wondering if there would be an issue with build-up of condensation behind the timber causing it to warp/go mouldy.
The walls in question are solid stone walls - all exterior - and all lime plaster has been removed/fell off, so the stone is bare.

I've read in a few places that there shouldn't be gaps between walls and cladding, but worried that if there isn't a gap, the moisture created on the stone when it's cold will have nowhere to go?

Any ideas?
Thanks.

Heat flows from hot to cold. Interstitial condensation is caused by warm, moist air passing from the warm side (kitchen) to the cold side (exterior wall) and condensing on, in your case, the inside surface of the stone.

First you could apply a breathable membrane to your stone wall to allow any moisture vapour to egress but resist ingress of water condensed on the surface. Then stud out the wall, ideally with C24 pressure treated rather than C16 interior studs and stainless fixings (coating all with preservative won't do any harm either), fill the void between the studs with rockwool / sheeps wool etc then staple a Vapour Control Layer (VCL) over the top. You can then fit your t and g to the studs.

It's important to note that fluids are very er, fluid, ie they move very easily. Imagine a bucket of water with a very small crack in it, it will empty relatively quickly. Well gas is a thousand times easier to move than a liquid, so any small gaps in the VCL will largely negate it's overall effect. The trick is to make sure you seal any gaps with vapour tape and also seal the t and g at the top and bottom. Yes, there will be tiny holes in the VCL from, for example, any 16 gauge pins / 3.2mm screws you use to fix the t and g, but these will largely be self sealed by the pin / screw itself and the pressure of the timber. (If you want to be pedantic you could squeeze a small line of hybrid adhesive / sealant and smear this behind the areas where you plan to screw / nail which will help to seal around the fixing)

It's also important to ensure the exterior surface of the wall is free from any waterproof coatings and that the joints are breathable (lime) and in good condition.

Remember. Water vapour is attempting to move from your kitchen to the outside (hot to cold). Having vents simply allows that moisture to condense on your stone walls behind the t and g. It may be counter intuitive but colder outside air has a lower dew point and is thus drier. The breathable membrane resists the passage of condensed water droplets inwards but lets warm water vapour past into the stone / lime mortar. The VCL will stop any interstitial water vapour coming through into the t and g.

Unless you have visible pooling water at the bottom of your wall, eg like in a basement where you might want to fit a drip drain membrane and perimeter drain, then you should be ok. And considerably warmer.

 

[Weetabix]

Heat flows from hot to cold. Interstitial condensation is caused by warm, moist air passing from the warm side (kitchen) to the cold side (exterior wall) and condensing on, in your case, the inside surface of the stone.

First you could apply a breathable membrane to your stone wall to allow any moisture vapour to egress but resist ingress of water condensed on the surface. Then stud out the wall, ideally with C24 pressure treated rather than C16 interior studs and stainless fixings (coating all with preservative won't do any harm either), fill the void between the studs with rockwool / sheeps wool etc then staple a Vapour Control Layer (VCL) over the top. You can then fit your t and g to the studs.

It's important to note that fluids are very er, fluid, ie they move very easily. Imagine a bucket of water with a very small crack in it, it will empty relatively quickly. Well gas is a thousand times easier to move than a liquid, so any small gaps in the VCL will largely negate it's overall effect. The trick is to make sure you seal any gaps with vapour tape and also seal the t and g at the top and bottom. Yes, there will be tiny holes in the VCL from, for example, any 16 gauge pins / 3.2mm screws you use to fix the t and g, but these will largely be self sealed by the pin / screw itself and the pressure of the timber. (If you want to be pedantic you could squeeze a small line of hybrid adhesive / sealant and smear this behind the areas where you plan to screw / nail which will help to seal around the fixing)

It's also important to ensure the exterior surface of the wall is free from any waterproof coatings and that the joints are breathable (lime) and in good condition.

Remember. Water vapour is attempting to move from your kitchen to the outside (hot to cold). Having vents simply allows that moisture to condense on your stone walls behind the t and g. It may be counter intuitive but colder outside air has a lower dew point and is thus drier. The breathable membrane resists the passage of condensed water droplets inwards but lets warm water vapour past into the stone / lime mortar. The VCL will stop any interstitial water vapour coming through into the t and g.

Unless you have visible pooling water at the bottom of your wall, eg like in a basement where you might want to fit a drip drain membrane and perimeter drain, then you should be ok. And considerably warmer.

Thank you for taking the time to reply!