Painting join between plaster and stone?

[Clover]

What is the correct way to paint the edge where the green wall meets the stone?
Do I need to chop off the edges of plaster to create a neat line (is there a special tool)? Or fill it with something to create a neat line? Or just paint across the mortar using my eye to create a neat line? Or do I just paint the jagged edge shapes with a small brush?

[dewaltdisney]

To my eye it looks like somone has decided that the old chimney arch would make a feature. Personally I would plaster over to bring the edge down to the newer concrete lintel. I would then look to laminate on a fake Bressumer beam ( a thin section of wood veneered on to look like a solid) to make it look in keeping. Just an idea.

DWD

[Clover]

It was left like that a few months ago as it suffered from damp. The old damp (I think gypsum) plaster was chopped out and repointed with lime mortar.
I love your idea dewaltdisney, as I have Bressumers in other rooms. But wonder if I should first let it ‘breathe’ for a while?

[dewaltdisney]

Well, I would have thought the latent heat retained by the stone from the stove heat would do that for you as we have entered heating season again. It depends on your preferences as there will be degree of wetness if you lime plaster over the exposed brickwork. If you decide to leave it then the existing paint line looks neat to me. Gluing a thin section of oak on the lintel would be easy to do for a good effect.

DWD

[premierdecorators]

It sounds like you're navigating a tricky painting project! Here’s a breakdown of your options for painting the edge where the green wall meets the stone:

Using Painter's Tape: This is probably the easiest way to create a neat line. Apply a high-quality painter’s tape along the edge of the stone, pressing it down firmly to prevent paint bleed. After painting, remove the tape while the paint is still slightly wet for the cleanest edge.

Small Brush Technique: If you prefer to paint freehand, use a small artist’s brush to carefully paint along the edge. This method gives you control and can work well, especially if the edge is jagged.

Filling the Edge: If the edge is particularly rough, consider using a flexible caulk or filler designed for stone and plaster. This can help create a smoother transition before you paint.

Tool Options: If you want to cut back any rough edges, a drywall saw or a chisel can be used to create a cleaner edge. Be cautious with this approach, as it can alter the structure of the plaster and stone.

Consider Moisture: Given the past damp issue, it’s wise to let the wall breathe before adding any additional layers like plaster or paint. Ensure everything is completely dry before proceeding.

Dewaltdisney’s suggestion about adding a Bressumer beam sounds great, especially if it complements other rooms! Just keep in mind the drying time for your wall and the potential for moisture issues before committing to that design choice.

Whatever method you choose, just take your time and it will turn out beautifully!

[Clover]

Premierdecorators, that is really helpful.
I actually love a tricky project. Such satisfaction when complete!

So I tried sanding the edges of the green paint and was really surprised how it smoothed out the look. Instead of jagged edges, it’s now softer and more curvy, so flows better and will be much easier to paint. I had actually bought a lime filler in anticipation of filling, but don’t think I’ll need it.

And it’s an artists brush all the way for me. Time consuming I know, but thankfully I have a steady hand and a shed load of patience.