breathable coating for bare stone wall

[piapiapiano]

Is there such a thing as a breathable coating for bare stone walls? Is such a thing necessary? We're planning on having at least one exposed stone wall in our house, and people keep asking us how we're going to seal it.

We also want to leave one wall with bare lime plaster, and again people are asking us how we're going to seal it.

Has anyone any experience of living with bare stone or plaster indoors? Thanks in advance!

 

[MdB]

We have two end walls of friable poor quality sandstone which is unsealed. Works fine and hasn't fallen down yet....

 

[Nigel Watts]

Lime wash or distemper.

 

[FamilyWiggs]

We have plenty of bare sand and limestone inside. Walls, inglenook, etc. None of it is treated, and it is fine. It was well washed and brushed after lime pointing and three years later, I can't see any issues for not having sealed it. it doesn't create lots of dust and leave powder on you if you touch it. I did try to put linseed oil on a coule of stones, and whilst it really brought out the colour in a beautiful way, I didn't proceed further.

We also have lots of new lime plaster inside; left untreated this is dry and powdery and looks rather flat and, well, unfinished . We painted with Earthborn clay paints - which are lovely and make the walls warmer and more interesting; they also enhance the texture of the plaster somewhat.

 

[MatthewC]

We also want to leave one wall with bare lime plaster, and again people are asking us how we're going to seal it.

I thought of leaving some plaster bare; it was very smooth fine plaster and looked very white. I decided to paint it with breathable matt white emulsion, at which that stage I realized that the plaster actually wasn't white in any case! Unless you use some really fine and wonderful (i.e. even more expensive) lime plaster skim, I think the roughness would always look poor.

 

[Lime Plasterer]

Hi
The only breathable coating for any type of walls regarding period property is lime putty & sand applied in 3 coats & then lime washed or painted with breathable paint. Please do not use any type of sealer's or you will trap moisture which will then produce damp

 

[Keithj]

I had some photos of our interior lime plaster with no coats, and up to five coats of limewash - but of course I can't find them now.

The raw plaster looked like pale rough sandpaper, and would shed sandy bits if rubbed against. Not the way to leave it, I'd say.

The first (mist) coat made it a bit smoother, but a much better colour.
By the fifth coat, it was smooth and hard, and doesn't rub off (even when the vacuum cleaner bashes into it - ahem).

 

[piapiapiano]

Okay. Thanks for all the advice!

Looks like it'll be fine to leave the stone wall as it is, after a bit of a wash. Will report back if there are any problems.

As for the bare lime plaster -- this is what happens when your husband is an artist obsessed with texture. He loves the texture of the exposed plaster, so it's staying for the time being. If it turns out to be not practical to live with then we'll give it a couple of coats of limewash.

Just good to know that, as we suspected, putting any kind of sealant on these walls would be a mistake.

 

[MdB]

One of our neighbours has a stone wall that has been varnished to within an inch of its life - it isn't good. The difference between hers and ours is dramatic and I very much know which one I prefer.

 

[Feltwell]

Agreed - "varnished" shiny stone walls look hideous. Another forum I've seen recommends using PVA as it's breatheable! :roll: (You would have thought PVA usually being listed under adhesives and sealants would be a slight clue to it's likely breatheable properties).