Internal repointing necessary if it’s being re-panelled?

[Pete S]

Hi All,

Brand new to the page and forum. We own a stone cottage in Argyll in Scotland which we are working on renovating.

I am currently removing some panelling in a downstairs bedroom to check the wall behind it. I’m finding some areas with a lot of dirt/sand/disintergrated mortar and it looks like the walls could do with repointing. (Please see the photos)

Im wondering whether I need to repoint the walls if I am going to keep them panelled. We were questioning whether we should insulate behind the panels but from reading websites and books with info from SPAB we were just going to leave the 2 inch gap so there is breathing room incase moisture gets through.

The room is north east facing so barely gets any sunshine on it (and it’s Scotland!) so it is colder inside and wetter on the exterior. We are planning on having a wood burner installed in the room and run a radiator large parts of the day.

Any advice would be greatly appreciated!

Pete

 

[aockenden]

What’s the condition of the backside of the existing panelling? Is it dry and free from mold / rot? If everything is fine back there then I would take the approach of just hoovering out all the loose stuff and deliberately NOT repointing it, as the gappy stonework may be letting in drafts which are helping to trickle-ventilate the cavity and keep it dry. And no matter what I would definitely re-panel with a natural solid wood, not MDF or something like that. MDF doesn’t handle moisture well at all. I would also paint the back side of the new solid-wood panelling with a linseed oil paint (including a turps-thinned primer coat).

 

[fernicarry]

we were just going to leave the 2 inch gap so there is breathing room incase moisture gets through

Thats how buildings in our part of the world are intended to work. It will be ventilated from the solum below the floor and up into the loft. Downside is that the ventilation can give rise to a howling gale in the living spaces so they are always difficult and expensive to heat.

If the debris behind the panelling has blocked the air flow then you may start to get localised damp spots so for that reason repointing or parging to stabilise it may be a good idea. Or you could just hoover it all out and it'll be good for a few more decades.

Are you replacing all the panelling? Looks like quite a substantial area so won't be cheap and you may regret it when you see the typical quality of modern timber!

If you do have to take it all off then I'd consider a breathable IWI system. I'm doing one in part of my back room at the moment. Whether losing the ventilation within the wall will lead to problems only time will tell but the ever worsening economics of running this place dictate I have to try something.

 

[Pete S]

Thats how buildings in our part of the world are intended to work. It will be ventilated from the solum below the floor and up into the loft. Downside is that the ventilation can give rise to a howling gale in the living spaces so they are always difficult and expensive to heat.

If the debris behind the panelling has blocked the air flow then you may start to get localised damp spots so for that reason repointing or parging to stabilise it may be a good idea. Or you could just hoover it all out and it'll be good for a few more decades.

Are you replacing all the panelling? Looks like quite a substantial area so won't be cheap and you may regret it when you see the typical quality of modern timber!

If you do have to take it all off then I'd consider a breathable IWI system. I'm doing one in part of my back room at the moment. Whether losing the ventilation within the wall will lead to problems only time will tell but the ever worsening economics of running this place dictate I have to try something.

Thanks very much for the advice. It's good to know theres someone else on here who also deals with a stone house in the same difficult Argyll weather.

I can see now I've been poking around how the solum helps with ventilation. One section has been fully closed off with fallen debris from the wall and the wet and rot in the floor and wood all around is very bad. I actually have drips coming down the stones in this section so trying to work out what to do next.

We're keeping the panelling and going to try and reuse the stuff I've removed as we know the timber quality will be much higher as you say.

I hope you're breathable IWI system works out for you!

 

[Pete S]

What’s the condition of the backside of the existing panelling? Is it dry and free from mold / rot? If everything is fine back there then I would take the approach of just hoovering out all the loose stuff and deliberately NOT repointing it, as the gappy stonework may be letting in drafts which are helping to trickle-ventilate the cavity and keep it dry. And no matter what I would definitely re-panel with a natural solid wood, not MDF or something like that. MDF doesn’t handle moisture well at all. I would also paint the back side of the new solid-wood panelling with a linseed oil paint (including a turps-thinned primer coat).

Thanks for the advice. Still questioning what to do about repointing. I think not doing it might be good as it just seems to fall out over time and cause a damp and rot issue later on.

We're going to reuse as much of the panelling as possible as it looks like better timber than some of the new stuff.

 

[a twig]

I would re-point it personally but that’s probably just my strange brain that would struggle with feeling like I’d been lazy and only done half a job then hidden it behind the panelling

 

[Pete S]

I’ve spent the evening taking the panelling out of what I’m guessing was once a larder? (Any guesses welcomed)

The wall is north east facing and thinner than the rest of the wall, it’s around the same depth as the fireplace.

It’s clearly been wet behind there for a long time, the stones are dripping and there’s a yellow fungus of some kind happily thriving back there. I’ve also found a cave spider which apparently only live in permanently dark, damp places and aren’t that common to find.

The ends of the floor boards underneath are very rotten and there’s a lot of what I believe is debris around them blocking the air flow gap.

I’m wondering if it’s just this that could have caused so much moisture in this space? If it was cleared out would the airflow get it dry enough?
I’m concerned that there may be more reasons why it’s so damp, thinness of the wall, external mortar etc.

The large timber lintel above is also rotten and has signs of woodworm so I’ll have to replace that some how.

Any help on what to do next would be greatly appreciated. Im new to this and although I’m reading the books im struggling to know what to do with each problem I’m running into.

Thanks

 

[fernicarry]

what I’m guessing was once a larder?

The "press", as the older generation would call it, a cupboard recessed into the wall. We have a few of these next to fireplaces where the wall is extra thick. The rule of thumb here seems to be either a window or a press on the wall next to the fireplace. They do tend to be cold and foosty inside. One of ours had a wine storage rack in it...

You're not going to get great air circulation around the back of that because its closed off at the top. I'd go the other way and try to exclude air as much as possible behind the panelling so that you avoid the tendency for warm air to condense. Parge the stone with insulating plaster and maybe a thin layer of some squashy insulation between that and the panelling. I'm doing the recess in my back room in this way as part of the IWI project (not finished yet because I need to reproduce the panels as a previous owner ripped them out).

You'll need to figure out why its so wet in the first place and address the root cause. Is the adjacent fire flue and its chimney stack in good condition? If its not then it will allow water deep into the wall. Check all the usual suspects like external pointing, rainwater goods, ground levels etc. There is someone on this forum who is good at identifying funghi (@Matt Green I think).

The lintel does look a bit suspect. Personally unless there are signs of movement I'd leave it be as it will be quite an operation to replace it. The fire flue will have stones running all the way through the wall tying inner and outer leaves together which will make that area a good deal stronger than it would otherwise be. In the great scheme of things its not a terribly large span to bridge versus the thickness of the wall. But don't take advice on a forum as gospel, get it checked out by an engineer if you are concerned.

I did replace the lintel over our front door, but that had literally crumbled away to nothing due to a leak from the roof valley directly above it. We maneuvered sections of 4x2 on their edge into the gap one by one, forced them up tight with wedges and packed above with lime mortar. Quite sketchy as the stones above the former lintel were very keen on detaching and falling down when disturbed. Even so there was no sign of movement in the stonework above but this case had passed my threshold for "it'll be fine". Same leak took out several joist ends above the door and had presumably carried on for decades hidden behind the shower cubicle. I only spotted it after ripping out the shower and seeing a pinprick of daylight through the sarking boards.

 

[Cubist]

Seconded and confirmed too that Matt Greens the GoTo Guy for all things growing or living in dark places.

 

[Matt Green]

Ooooo good picture of mine rot- can I steal that one?

Wood-boring weevils there too, I love those little guys. You can tell because the exit holes are ragged rather than circular and it's a textbook case too. the end grain of the board suck up water from the all, decay, and weevils move it to the decayed portion, the remainder being too hard for them to chew through. Eventually they cause an air gap, the boards dry and the weevils move on.

The debris falling down behind the panelling bridged the original air gap causing water to get into the timber, it's a feature of wainscoting which should always be viewed as sacrificial or at the very least requires a plan to periodically clear out the bottom of the void.


M.
-never seen wainscoting solve a problem

 

[Matt Green]

Seconded and confirmed too that Matt Greens the GoTo Guy for all things growing or living in dark places.

I spend too much time considering dank corners of buildings, it's true.