Exposed Internal Wall

[ggx32]

HI,

I have an exposed internal wall in the kitchen at the base of the stairs. The wall is crumbly with patches of plaster and cement where at some point in the past someone (not me!) has attempted to stabilise it. What should I do to stop it deteriorating further?

regards,
Dan.

Picture attached.

 

[tobydog]

Hi Dan and welcome to PPUK. Just a number of questions.

1) Is the part of the wall in question damp?
2) What is on the other side of the wall in terms of space and covering?
3) Is it possible that the side of the wall in question was once an exterior wall? The reason I ask is because the bevel on the top course of bricks suggests this might have been the outside of a wall plinth.
4) What is the lower wall comprised of? Is it stone of some sort?
5) Is the mortar the original lime mortar?
6) What is the wall like under the stairs and behind the wooden unit?

Hopefully your answers will prompt a helpful response.

 

[Penners]

Hello Dan,

One other question - are you prepared to render that small area of exposed masonry?

 

[ggx32]

Hi, thanks for the response - my answers inline below:

Hi Dan and welcome to PPUK. Just a number of questions.

1) Is the part of the wall in question damp? No
2) What is on the other side of the wall in terms of space and covering? The living room is the other side but it has another internal wall with a 5 inch gap between this one and that one.
3) Is it possible that the side of the wall in question was once an exterior wall? The reason I ask is because the bevel on the top course of bricks suggests this might have been the outside of a wall plinth. Yes it may well have been, the property is a good 450 years old in places so anything is possible.
4) What is the lower wall comprised of? Is it stone of some sort? I don't think it's stone, its very unstable and crumbles at the slightest touch.
5) Is the mortar the original lime mortar? Yes it appears to be
6) What is the wall like under the stairs and behind the wooden unit? The wall continues behind the unit and is in the same state of repair, not sure under the stairs as this is not accessible but I imagine it continues to the current outside wall about 6 feet to the right of this photo
7) render - My wife would shout YES! as she is sick of hoovering the debris off the kitchen floor but (if possible) I would prefer a solution where the wall can be stabilised and remain on display. TBH it will be cost that probably determines the course of action we follow.

thanks for reading,
Dan.


Hopefully your answers will prompt a helpful response.

 

[Penners]

Well, Dan, if your wife is in favour of rendering then that's the decision made, isn't it (for the avoidance of earache)? :wink:

Seriously, given your responses to the other questions, I feel that rendering is by far the best solution. Just be sure that you use a lime mortar render and paint it with limewash, distemper, clay paint or some such breathable surface finish. I reckon this should solve most of the problems with that little bit of wall.

 

[tobydog]

I think the problem with going straight for the plaster option is that the substrate is currently unlikely to support it. Dan mentioned that the surface currently crumbles to the touch and therefore there will be nothing for the plaster to cling to. Bit of a Catch 22. If you stabilise an unstable surface then it's just as likely to come off later in one big chunk rather than gradually as dust and pieces because what is behind is still not sound.

I'm at a loss to think what the material could be. It doesn't look like bricks, and for it to crumble so readily suggests some kind of sandstone even though it is grey. You could try scraping off part of the surface behind the wooden unit to see how far you might need to go to find a sound solid surface which you could plaster (harling first?) but you could be left with an awkward finish near the bevel.

If these are some kind of bricks / blocks then it's possible they are soft centred and not fully fired. Now the surface has gone, there's nothing to stop the inner part absorbing moisture from the atmosphere and continuing to crumble. I have this exact problem with some soft reds in our inglenook. You can clean and hoover up as much as you want but the hole just gets bigger. I can replace my bricks but in reality you probably can't.

Any other ideas / thoughts anyone?

 

[Flyfisher]

Is everything in the wall crumbly or is it just the mortar. The dark bits look like pretty solid stony stuff in the photo, though it's obviously impossible to tell just from that.

However, if the stony bits are solid and it is only the mortar that's crumbly, then I'd have thought the mortar could be raked out to about 1-2 inches deep (depending on the size of the stoy bits), which should then provide a very good key for some new render or, if a complete covering is not desired, then just stick to effectively re-pointing the wall.


Edit - just re-read Dan's answers to the stone question. Hmm. Well, if the 'stone' itself is very crumbly then I'm at a loss about how to leave it exposed while stabilising it at the same time. There may be some fancy chemical treatments for such a thing, but I'd be very cautious about how appropriate it would be.

If it was mine, I'd be thinking of rendering it, given that it's only a small section of wall. I suppose another option might be wood panelling - though if the wall is really very crumbly then fixings may be a problem.

 

[ggx32]

Hi Guys,

Thanks for all the feedback. I will take another look this evening and see if any of the wall is stable and try and get a close up of the material within it. I am coming rounf to the idea of just hiding it behind some render. I will post some more details later, thanks again for taking the time to respond.

Dan.

 

[worms]

Perhaps not completely relevant, but I have used the calcite/water off the top of my lime putty bin to help stabilise individual crumbly stones in my rubble exterior wall prior to lime washing. Seems to do some good, although it may only be acting as a key for the lime wash rather than actually stabilising the stones.

 

[ggx32]

I have had another poke at it tonight. It appears that flyfisher may be correct. A few of the stones are still quite firm but those that have lost their skin are crumbly.

So a lime based render would be best?

Dan.

 

[Penners]

So a lime based render would be best?

It's definitely what I would do. And, as Worms has observed, you could achieve some stabilisation of the friable surface by giving it a few coats of lime water before you render.

Whatever you do, don't cement render. This would seal the damp inside the wall and risk long-term problems.