Best covering for walls in 1890s terrace

[anddh]

I am currently in the process of having my kitchen renovated in my mid terrace house which was built in the 1890s. The house is of a soft orange/red brick construction with lime mortar (although has been re-pointed with cement). In the process of the kitchen renovation, it has been brought to my attention that in some areas the walls have no cavity, in some the cavities are fine and in other areas they're so full of old mortar etc that they may as well not be there. Currently, there appears to be a cementitious render on these walls (interior) followed by a skim of modern gypsum.

Am I right in believing that this should all be removed and replaced with lime plaster? My builder who is currently doing some brickwork on the house (with lime mortar ) has advised that I should paint some of this black bituminous stuff from floor to ceiling to prevent damp, but isn't this just going to cause damp later on?

The floor in said room is also concrete (DPM, followed by insulation and then underfloor heating pipes and screed) which I can't do too much about but I don't think should cause any issues. The main thing would be getting the walls breathing again.

Any advice would be much appreciated

 

[Abi Cott]

Welcome to the forum

In my opinion. In an ideal world taking these buildings back to how they were designed to work is the best way of preserving them and creating a dry warm environment.

However your concrete floor is probably preventing damp from dissipating and it's coming up the walls instead. If you can't alter the floor you are going to have to deal with the consequences of it or face constant peeling paint.
Sealing the damp into the walls has it's own consequences.
If cost was a serious issue and I was looking for something that met my needs without serious upheaval, my next question would be how reversible this would be by the next custodians. I'd want to do something that could be reversed by someone with the time and the money to treat the building the way it truly deserves.

 

[TheForge]

As with most situations if the cement render isn’t causing issues is there really a need to remove it? You don’t say there are specific issues only that the lack of a cavity has been brought to your attention. A more permeable lime plaster would be preferable and likely more authentic (although cement was in wide use by 1890 - both early cements, Roman Cements and OPC) but is it necessary or worth the trouble? I’d say that depends on whether there are any existing issues and how much of a purist you want to be. I suppose in theory the cement render may be more likely to create condensation and potentially encourage mould growth if moisture is trapped behind it and the wall cold.

Black bitumastic paint is a definite no and I would be very concerned regards your tradesmans knowledge and suitability to be working with lime mortar if this is his suggestion. Are you sure he’s not putting white cement or hydrated lime in?! Any such paint would be worse than the cement render in trapping moisture in the brickwork and is only hiding any issues.

Find the source or any damp/water ingress and address that first - leaking gutters, elevated ground levels on the exterior, damaged plumbing or drainage etc.

 

[anddh]

Thanks for the welcome and the reply Abi!

I am aware the concrete floor is not ideal, but as this is the first property I've bought and cost an arm and a leg, there's not too much I can do to reverse this _presently_. I was hoping though to prevent further damage if I possibly could. Do you have any suggestions?

Is the lime a good idea? Should I go for the black stuff? Another plasterer suggested plastic membrane half way up the wall and then cover with plasterboard (this sounds terrible!).

 

[anddh]

Thank you for your reply @TheForge. You have a good point there regarding the removal of the cement. I think this may actually cause more damage to the walls.

I'm definitely sure of my builder's ability to use lime. We supplied him with the material and he's very competent with it. I also agree that his solution of using the bitumen is questionable, but I have received nothing but questionable solutions so far and being a complete novice, this is why I've turned to the good people of this forum.

It would seem that there is no single best solution being that there are so many factors at play. How on earth are you supposed to get it right?!

 

[88v8]

Hello and welcome.

Yes, you're a bit stuck, really. A dpm that shouldn't be there. If there is damp under the floor, it will go sideways into the wall(s).
But as TheForge said, is there actually a problem? Not all floors are damp beneath.

Next consideration, is there a dpc? Could be slate, or bituminous. If so, that should stop any damp rising up the wall. So long as it hasn't been bridged internally or externally by cement render, or externally by excessive ground levels.

In an unfamiliar house, it can be hard to tell whether inherited bodges were a response to a problem, or a 'solution' that some tradesman flogged to an ignorant householder to deal with issues that didn't actually exist.

Yes, ideally the cement should all come off, and the wall be replastered in lime. But is there actually a problem?

Unusual to have a cavity at all, in that period. I wouldn't worry overly about its deficiencies.

Ivor

 

[plasticpigeon]

Great that you are repointing in lime, that will hep preserve the nice red bricks from damage in the event of freeze thaw or movement. I doubt your house has a cavity at all, very few houses had cavities on the 1890s. Are you by the seaside? If your house doesn't seem damp, then don't worry. If it does seem damp then as ivor says, the most important thing to do is make sure that the damp proof course, which is probably slate or bitumen hasn't been bridged by the cement or flooring.

 

[anddh]

Hello and welcome.

Yes, you're a bit stuck, really. A dpm that shouldn't be there. If there is damp under the floor, it will go sideways into the wall(s).
But as TheForge said, is there actually a problem? Not all floors are damp beneath.

Next consideration, is there a dpc? Could be slate, or bituminous. If so, that should stop any damp rising up the wall. So long as it hasn't been bridged internally or externally by cement render, or externally by excessive ground levels.

In an unfamiliar house, it can be hard to tell whether inherited bodges were a response to a problem, or a 'solution' that some tradesman flogged to an ignorant householder to deal with issues that didn't actually exist.

Yes, ideally the cement should all come off, and the wall be replastered in lime. But is there actually a problem?

Unusual to have a cavity at all, in that period. I wouldn't worry overly about its deficiencies.

Ivor

Thanks for your reply Ivor. You're so right about the bodges. I observed my neighbour's landlord (who used to own my house too), fill an air brick at the front of the house with expanding foam just a few days ago. Luckily mine are all fine!

It does look, where I can see, that I have some sort of slate dpc but I can't be 100% sure how intact it is.

Anyway, as for the plastering... Some of the walls have no plaster on them at all so assuming I'm not taking the cement off the others, what would you suggest for the bare walls?

 

[anddh]

Thanks plasticpigeon. I'm not by the seaside, I'm in the middle of Surrey the house doesn't seem to be damp at all which is great. I just want to make sure it stays that way, by doing things right and eventually sorting some of the bodges out.

 

[88v8]

Afterthought.... kitchen, underfloor heating....
I hope the heating doesn't extend under the cupboards, otherwise you can forget using them for food storage. :shock:
The sort of daft thing that builders do.

If you're putting in modern units, you could improve the situation by replacing the bottoms of the units with fireboard, and inserting a lot of brass vents in the kickboards.

Ivor

 

[anddh]

Afterthought.... kitchen, underfloor heating....
I hope the heating doesn't extend under the cupboards, otherwise you can forget using them for food storage. :shock:
The sort of daft thing that builders do.

If you're putting in modern units, you could improve the situation by replacing the bottoms of the units with fireboard, and inserting a lot of brass vents in the kickboards.

Ivor

Don't worry Ivor, the undefloor doesn't run under the units!

 

[88v8]

Anyway, as for the plastering... Some of the walls have no plaster on them at all so assuming I'm not taking the cement off the others, what would you suggest for the bare walls?

Sorry, didn't see your post. Surrey, eh. If you edit your Profile to show your location, that may help with local recommendations. We used to live in Shepperton.

The thing about lime is its breathability which serves to offset the inherent dampness of early houses lacking dpm and dpc.
Damp arising from no dpm, is breathed outwards, and external damp arising from no dpc is dissipated.
If your house has a dpc, and is not damp, there is less need to worry.

Upstairs I'd just go for gypsum, no harm will be done.
Downstairs, if you are plastering anyway, I'd go for lime. Your bare walls are breathing, assuming they aren't coated in plastic paint that is, shame to stifle them. I'd also have the cement pointing removed from the exterior. (Tip: this should not involve an angle grinder.) This will allow the exterior to breathe.

Good if there is a dpc. Assuming it has not been bridged by ground levels, and is not being bridged by splash from hard perimeter surfaces such as paving, it is unlikely to stop working.

However, before you take the decision that it's not damp, buy a couple of hygrometers and see what they show you.
https://www.amazon.co.uk/hygrometer/s?page=1&rh=i%3Aaps%2Ck%3Ahygrometer
Other retailers are available.

You mention aribricks; are these in the room for ventilation, or under a suspended floor?

Ufh not under the units. So, there are some intelligent builders around. There's hope for us yet
Neighbours up the lane had a hideous modern, expensive, architect-designed extension put on their GII house, it has centrally heated kitchen cupboards hehheh.

Ivor

 

[anddh]

I think my posts are only just getting approved, so it wasn't actually there before

Thanks for all the advice. My builder who has just finished the other work is going to quote me to repoint in lime. One quote I received was for £12000!!

I'll continue to hunt for a decent plasterer. I'm not keen on the fixing plastic sheeting to the walls followed by plasterboard suggestion of the first guy that quoted.

I have differently positioned airbricks. Some of which are higher up in the wall for general ventilation and the others are under the suspended wooden floor (one at either end of room which was knocked through by previous owner). Unfortunately none of these are in the kitchen, but as the floor isn't suspended in there it's not too much of a problem.

The hygrometers, do they just measure humidity in the room? My Nest thermostat has this function so may put it in the kitchen to see what's going on. It currently reports 39% in my living room.

Your neighbour's extension sounds really unfortunate

 

[88v8]

Relative humidity, that is to say relative to temperature.

39% :shock: Jeez, that's like the desert.
In comparison, currently we have about 45% in our dining room which is as low as we ever go, and this morning around 64% in the sitting room where there is newish lime plaster that's still curing. When the plaster was new and I was misting it four times daily, and the room was unheated, the humidity hit 94% and mould was happily sprouting everywhere.
In the studio at the end of the cottage where there is a dpm, plus a large expanse of stone wall with no dpc, it's 71%. I think a dehumidifier will have to take up residence there.

39%, well no damp problem then.

Air bricks under a suspended floor are important, surprising how often they're lacking or blocked. Those in the wall are on the whole a good thing for the health of the house and its occupants, although less important than when open fires were the norm.

Yes, keep away from the plastic sheet merchants.

£12 grand for repointing sounds an awful lot, unless it's a very grand house with gauged brickwork.

Your neighbour's extension sounds really unfortunate

We call it the toilet block

Ivor

 

[Flyfisher]

39% :shock: Jeez, that's like the desert.

Yes, definitely at the lower end of a healthy indoor climate.
https://www.telegraph.co.uk/finance/property/advice/9614700/What-is-the-recommended-humidity-for-a-home.html

Or, for a more scientific analysis:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1474709/