Door frames & Blue grit

by Martin
(Wiltshire)

Hi Paul,

Great site, just wished I found it earlier before I spent thousands of pounds on very unreliable plasterers. But then I wouldn't have found this site if they were reliable I suppose!

Anyway I have attempted my first small wall and am 85-90% happy with it considering. I definitely got caught out on the suction of the wall even though I sprayed it down with water first. Do you think that had anything to do with the layer of Blue Grit the previous plasterers had smothered the wall in?... It has been on for months like many other walls in the house from a previous over eager plasterers labourer!

I certainly found it frustrating on the first coat as the Blue grit was scratching the trowel badly and sounded awful. Is there any advantage of Blue grit over PVA? Can I add PVA over it if it dries out too quickly?

Also is it best to take door frame architrave off when plastering around it?... I did but wondered if I was just making extra work for myself in the long run i.e. it may be easier for a plasterer but when you are then doing the carpentry work is it cost/time effective?..(that may be an unfair question to a plasterer!)

Thanks again,

Martin.

Hi Martin,

Blue Grit is basically a slurry mix to ensure good adhesion. If extra adhesion is needed, I tend to use PVA and add sand into it. For a wall with a mechanical key the PVA will often just act as a sealer to control suction but where a mechanical key is absent and the PVA totally dries out - then the grit provides this mechanical key.

PVA will act as sealer and control the suction for you.

Architraves can be left on - no problem, however a bit of extra care is needed to ensure that it is flat, along the whole length where the plaster meets the wood. You'll also need to keep the wood clean with your brush.

Paul