Internal Stone Wall Repair

[Trif]

About to start on my smorgasbord kitchen walls , just wanted to check that I'm doing the right things and not missing anything.

Treat dry rot on the stone
Remove cement/concrete/mortar as much as possible
Scrape out old lime mortar?
Brush, wash, dry out
Repoint (using hot mixed lime mortar)
Replace some of the studs

I'm using fibre cement boards (the lightweight ones) for the walls.

What do I do at the bottom? Are floorboards supposed to go right up to the stone?

Many many thanks

 

[fernicarry]

The bricks are probably laid in cement so not sure what hacking out part of that on the inside gains you. Is that a doorway that became a window opening?

Where I have exposed the inner face of the stone my standard approach now is to parge the wall with a breathable insulating plaster. Same process, rake out loose bits, wash down then apply plaster.

The cavity formed by the studs is usually intended to be ventilated to keep the inner face of the stone dry so floorboards stop short of the wall. You could also consider insulating between the studs with something breathable.

Why cement board? Doesn't sound particularly breathable.

 

[Trif]

Thanks fernicarry, that's really helpful

I thought about insulation because it's bloody cold in the flat in general but I know it's all supposed to be allowed to breathe, so I wasn't sure.

It's a first floor flat, and i think they probably put the bricks in when they put double glazing in. The wall maybe fell apart??

I decided to use cement board instead of plasterboard because it's easier to work with and lighter - I'm doing the work myself and I'm not what you'd call Amazonian
Are they likely to cause damp/ condensation problems even with a cavity between?

Thanks again

 

[fernicarry]

they probably put the bricks in when they put double glazing in

Ah ok, maybe the size of the opening was reduced to suit the DG units going in. Or possibly to raise the height of the sill so that it wasn't below worktop level (its a kitchen, right?). Or could have been the stonework was loosened due to water leaking past an old timber window frame and it was easier to rebuild with bricks. I can see all of those possiblities from where I'm sat...

Are they likely to cause damp/ condensation problems even with a cavity between

You might get away with that. The lightweight cement boards designed as tile backer boards are probably the least breathable of modern boards. Plasterboard would be a slightly better choice and you can get it in half and quarter sheets to make handling easier. But you'll still have precious little insulation and drafts wherever there are gaps in the wall like at the junction with the floorboards or around plumbing and electrical fittings (can try sealing with airtight tape).

Personally whenever I have reason to strip away an external wall I try to put it back as airtight and as well insulated as possible. This country's energy policy means that its only going to get harder to keep traditional properties comfortable so if its chilly now, wait until you are mandated to use a heat pump instead of a gas boiler or the price of gas goes up tenfold because you are one of the few still using it. Its a reasonably modest investment now that should bring immediate benefits in comfort level and running costs.

If the wall has a tendency to get very wet, say due to driven rain, then I might want to leave the ventilated void, that is after all why its there. Whats the condition of the external face like? You can still insulate but you'd need to build new studwork set away from the stone and you'd lose two or three inches of floor area. You might not even need to worry too much about breathability in this case.

If its performing ok then I'd think about going the IWI route direct onto the stone using breathable materials. I'm currently chancing my arm with a wall that does get soaked by the rain but I'm doing IWI anyway because the room is like a fridge. In theory, even if the wall gets wet it can still dry itself out due to choice of materials.

 

[Trif]

Thanks v v much.
It's a first floor 1 bed flat (1842), no gas but the elec bills are gonna be through the roof (probably literally).

There's obviously been a lot of cowboy covering up in order to get it sold. Surveys seem a bit pointless when it comes to buying a property. Can't lift floor coverings, can't see behind anaglypta wallpaper, can't get in the loft... etc. But it's got some lovely features, so hopefully worth the work.

I'm worried about damp and mould because, as you suggest, externally it'll probably get quite wet, not least of all because it's west Scotland
Externally probably needs some repointing and corner guttering needs fixing.

That's a good point about smaller windows. What a shame.

Are you going to use glasswool for your insulation?

 

[fernicarry]

Surveys seem a bit pointless when it comes to buying a property

Yeah the mandatory Home Report is completely not worth the paper its not written on. Wish I was in that game. On the other hand if you knew in advance of the potential horrors then you'd never buy anything... Hope for the best, expect the worst.

Externally its a bit of a hotch potch of alterations, but the stone seems to have been fairly carefully pointed rather than buttering cement over half the surface like my place. Assuming its cement then picking it out and redoing it in lime might not be too involved but you would need the cooperation of your neighbours and/or Factor so that's probably for another day. I guess the rendered area is covering brick and its probably cement based so your external breathability around that area is never going to be good. That makes getting the inside face to work well more important.

Is there another flat above you? Wondering how well the ventilated void is working given that you are relying on upstairs and downstairs for air circulation. In my house the void is continuous from solum (under the ground floor) up to the loft. Or at least its intended to be, in places it gets choked up with debris, bits of plaster falling off the back of the wall and sand washed out of the joints in the stone. Wherever this happens and the wall finishes aren't breathable then I get dampness showing through. Given that that is out of your hands I'd suggest you have nothing to lose by going straight onto the stone with insulation so long as it and everything else you put on is breathable.

Are you going to use glasswool for your insulation

My current choice is IndiNature IndiTherm Hemp batts. Its stiff enough to stand up between studs but squashy enough for slightly irregular spaces. And its made in the Borders. See the thread bricked-up-fireplace-maybe-reinstate for what I'm doing.

 

[aockenden]

Repoint (using hot mixed lime mortar)

Honestly, the “hot mixing” thing is cultist dogma as far as I can tell. I wouldn’t bother. It’s definitely not worth the hassle and hazard of dealing with quicklime.

If you were planning to hot mix then you’re likely not a fan of NHLs, so just make your own non-hydraulic lime putty from quality fresh bags of powdered hydrated lime and then add in your aggregates to the putty and knock it up when ready to start the work. And as long as your hydrated lime is powdered, you don’t need to “age” it 3 months. That’s dogma as well (leftover from the days of lump-lime coming out of the kilns).

 

[Trif]

Thanks aockendon (I used to live near there! )

I've got premixed hot lime in a tub. The result of a lot of reading up. But yeah probably a bit over the top for the little bit i need to use it on.
I can't remember exactly why I went with the hot lime in the end but could be that it is supposed to be easier to work with
Definitely wouldn't go down the route of making it myself...

 

[Trif]

Yeah the mandatory Home Report is completely not worth the paper its not written on. Wish I was in that game. On the other hand if you knew in advance of the potential horrors then you'd never buy anything... Hope for the best, expect the worst.

Externally its a bit of a hotch potch of alterations, but the stone seems to have been fairly carefully pointed rather than buttering cement over half the surface like my place. Assuming its cement then picking it out and redoing it in lime might not be too involved but you would need the cooperation of your neighbours and/or Factor so that's probably for another day. I guess the rendered area is covering brick and its probably cement based so your external breathability around that area is never going to be good. That makes getting the inside face to work well more important.

Is there another flat above you? Wondering how well the ventilated void is working given that you are relying on upstairs and downstairs for air circulation. In my house the void is continuous from solum (under the ground floor) up to the loft. Or at least its intended to be, in places it gets choked up with debris, bits of plaster falling off the back of the wall and sand washed out of the joints in the stone. Wherever this happens and the wall finishes aren't breathable then I get dampness showing through. Given that that is out of your hands I'd suggest you have nothing to lose by going straight onto the stone with insulation so long as it and everything else you put on is breathable.



My current choice is IndiNature IndiTherm Hemp batts. Its stiff enough to stand up between studs but squashy enough for slightly irregular spaces. And its made in the Borders. See the thread bricked-up-fireplace-maybe-reinstate for what I'm doing.

Thanks fernicarry.
Your comment on surveys made me laugh. Although, buying a newer property seems to also come with a plethora of problems nowadays

Big shared loft above (I don't do arachnids, so I'm ignoring it for now).
Empty shop below.
I'm thinking I should get it surveyed on the government scheme really

Your fireplace project looks interesting.

 

[fernicarry]

Big shared loft above (I don't do arachnids, so I'm ignoring it for now).

There could be low hanging fruit in terms of opportunities to insulate up there. Definitely worth a look.

I was just sent upstairs to investigate a fluttering noise. My wife imagining a big scary thing with beak and talons. It was a butterfly...

 

[Cubist]

Big shared loft above (I don't do arachnids, so I'm ignoring it for now).

There could be low hanging fruit in terms of opportunities to insulate up there. Definitely worth a look.

I was just sent upstairs to investigate a fluttering noise. My wife imagining a big scary thing with beak and talons. It was a butterfly...

My various forays into our loft space have rendered me less concerned with the spiders living up there - despite the initial terrors induced by the epic Hollywood Movie like webs I found - as they are predominantly those long spindly legged, small bodied things that will happily get out of your way. Its the big, hairy, fast movers coming in from the garden and deep desire to take up residence in the bath that will have the First Lady, and me, jumping onto the nearest chair.

 

[Trif]

You do know they can climb chairs, don't you


I used to use hairspray on them but I'm a bit more Buddhist towards them nowadays

 

[Cubist]

You do know they can climb chairs, don't you

Unfortunately yes, and yet another reason why I hate gardening. Not long back my spidey senses were alerted to a foreign weight on my shoulder. Glancing round I met the face of one of the big, hairy fast movers staring back. It did not end well... for it or me!

 

[Trif]

Funny... when one mentions one's arachnaphobia... everyone starts telling scary stories about the horrendous things

 

[Cubist]

Funny... when one mentions one's arachnaphobia... everyone starts telling scary stories about the horrendous things

Arachnophobia, not so much. Snakes on the other hand produce a cloud of dust and burned out Nikes.

 

[paulc]

You do know they can climb chairs, don't you


I used to use hairspray on them but I'm a bit more Buddhist towards them nowadays

Get a cat - Mine is very good at catching spiders running around on the floor (I usually bring one or two in with logs for the fire). The monster also brought me a small rat over the weekend....

 

[Trif]

I was cat sitting the other day and I got exactly the same gift!

 

[Cubist]

This boy, together with his brother and mum, take care of all our visitors of that sort. Oh, and mum will take the odd cat given the chance.

 

[Trif]

Ok. Getting back to business...

It would seem most of the internal kitchen back wall is brick.
What do I fill gaps and cracks with?
Is it a waste of time to use lime mortar on brick??
I mean, can i use something else to avoid having to gouge out the concrete


Also, what would you do with the gap between the window frame and sill?
Fill or just cover over

Many thanks

 

[aockenden]

Ok. Getting back to business...

It would seem most of the internal kitchen back wall is brick.
What do I fill gaps and cracks with?
Is it a waste of time to use lime mortar on brick??
I mean, can i use something else to avoid having to gouge out the concrete


Also, what would you do with the gap between the window frame and sill?
Fill or just cover over

Many thanks

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no it’s not a waste of time to use lime mortar on and around your bricks. Can we get a zoomed out pic of the gap between the frame and sill?