Painting plaster in a Victorian home

joe90mitch

Hi all,

My partner and I recently moved into a Victorian terrace (believe it was built in 1890s). It has stone exterior walls. We were going to buy some Farrow and Ball modern emulsion (I appreciate there's a lot of chat relating to the pros/cons of F&B, we can save that for another time ), but when speaking to their sales team they queried the type of plaster used. We were wanting to get this "modern" emulsion paint to paint the lower half of our hallway and staircase as it's hardier (and we're getting a dog!).

They questioned if lime plaster was used in the property as it's older and, if so, this product isn't suitable as it's not breathable.

I was hoping for some steer on here. I'm really not sure how to tell what the type of plaster is and how applicable this query is. Our hallway has 1 external wall - it has our "front door" on it which leads out into a covered alleyway between us and our next door neighbour. I couldn't tell you if lime plaster has been used, but it's certainly a solid wall. I guess F&B are advising against the modern emulsion as it could cause issues with damp evaporating. So my questions would be: 1. does it matter as much if the wall is covered - i.e. will the damp issue be mitigated by the fact it's covered by the terracing. 2. is the fact that we're only painting the lower half useful, or could it still easily trap a lot of damp. 3. is this a factor on the staircase also - where it's a stud wall with plasterboard on (no idea when it was last done) and a solid brick wall halfway up that is the party wall with the other neighbour.

Sorry if that's a bit vague. Feeling a bit lost and confused on this and struggled to find useful answers on Google. The previous owners seem to have whacked a fairly thick layer or two of emulsion onto the exterior wall in the past, so I would be somewhat surprised if they had applied this much thought - so am wondering how careful we need to be? There was no sign of any blistering or damp and we actually had a damp survey done before moving in which flagged an issue at the front of the house relating to a downpipe but he basically said everywhere else is fine.

Thanks

FreeBear

Scrape the paint off in an inconspicuous area - Lime plaster will be a shade of white (unless it has had pigments added to it when originally put on the walls). A modern gypsum plaster will be a brown to pink colour.

Stud walls with plasterboard, you can use just about any paint you like. Being an internal wall (and modern materials), breathability is not a concern.

With the external walls, I would recommend a lime wash or clay paint to maintain the breathability. But if a modern emulsion has already been slapped on the walls, then breathability will have been compromised. In which case, go ahead and use the F&B.

Hats off to the supplier for pointing out the perils of modern paints over lime plaster - Most places would not have said anything.

rob7475

If you've got original lime plaster, you'll be very lucky if it's a good enough smooth and flat surface to take a flat emulsion and give a good finish.
As for it being breathable, many lime plaster walls will have been skimmed with multifinish over the years which isn't breathable. 99% of people won't have had any damp issues.

joe90mitch

Thanks both. @FreeBear - I'll try giving a go at scraping some off, we're thinking we might just crack on with painting the staircase then in that case and leaving the hall external hall as-is for the time being and figuring out what's what. Agreed that I was impressed that F&B flagged this, they effectively made me not make the sale so was good to know some sales people are very principled

@rob7475 - it's a very smooth finish on the wall - both in terms of the "squareness/flatness" of the plaster and the finish of the previously applied paint. Maybe it's just been done with the multifinish as you said. Maybe we shouldn't worry so much if there's no visible sign of damp and it wasn't flagged on the damp survey?

Doozergirl

joe90mitch said:

Thanks both. @FreeBear - I'll try giving a go at scraping some off, we're thinking we might just crack on with painting the staircase then in that case and leaving the hall external hall as-is for the time being and figuring out what's what. Agreed that I was impressed that F&B flagged this, they effectively made me not make the sale so was good to know some sales people are very principled

@rob7475 - it's a very smooth finish on the wall - both in terms of the "squareness/flatness" of the plaster and the finish of the previously applied paint. Maybe it's just been done with the multifinish as you said. Maybe we shouldn't worry so much if there's no visible sign of damp and it wasn't flagged on the damp survey?

I'd put any amount of money on the existing paint being a modern vinyl emulsion as the vast majority of people wouldn't even consider breathable paints and the vast majority of paint sold is vinyl based.  

If you have smooth, painted walls in a Victorian house, there's almost zero chance that you have the original lime plaster finish.  Again, most people aren't aware that the external walls, particularly will benefit from being breathable and lime.  And if they are, they don't really care.  

F&B are being responsible but I would imagine that it's too late.  Dulux is probably already slapped everywhere.  

joe90mitch

Thanks @Doozergirl. Yeah the finish of the previous people's paint is definitely smooth. The walls are a bit "wobbly" here and there (i.e. bulge inwards/outwards slightly in places), but all the paint on top is very smooth and a consistent enough finish. The specific wall in the hall is pretty much dead straight lines though, so presumably has had a skim layer done "recently" (compared to Victorian era anyway!)

I'm guessing from all the responses then that it'll hardly matter if I paint F&B's modern emulsion line on then. The "damage" is done is how I'm taking it and if it really was that big an issue we would have seen damp issues (and had them hopefully flagged in our damp survey). I'm also assuming that if it really was a big issue the only recourse would be to take back all the plaster and re-do it with lime plaster? Just asking the last question out of interest, in case in the future it ever did turn out to be a problem (I can overthink at times haha)

FreeBear

joe90mitch said: I'm also assuming that if [damp] really was a big issue the only recourse would be to take back all the plaster and re-do it with lime plaster? Just asking the last question out of interest, in case in the future it ever did turn out to be a problem (I can overthink at times haha)

If it is just paint over lime plaster, a belt sander and/or orbital sander will get it off - Very messy & dusty work - Or you could try a paint stripper (X-Tex is pretty good, even although it is marketed as an Artex remover).

Once the paint is off, and you are back to solid lime, a skim of fine finishing plaster can then be put on.

If you have a skim of gypsum over lime, quite often, you have to go back to bare brick - More mess and expense !

joe90mitch

Thanks again @FreeBear. I hope I'm interpreting all this correctly, but from the replies (and the fact that the damp survey did not flag any issues in this wall) would I be interpreting your explanation of how to strip back to lime plaster as probably only required in my situation if we were to paint it with some emulsion and then over time we did start to notice symptoms of damp that presumably have arisen from the paint used? And that in reality we should probably be OK because it's already been painted and (as of right now) there's no sign of damp issues.

FreeBear

Yup. If a problem with damp emerges, then look at stripping back.