Plaster beads rusting and celing tops

newhouse87

New, air tight house, plasterers forgot to put on primer when installing ceiling top things and now rusting through. Any solutions much appreciated. They have since sprayed them but coming through again, will be turning on heating newt week so maybe that will help if we spray again. Bead edging around windows also rusting.

moceri

I can only speak from my own experience. After walls were plastered, I painted any metal beading with aluminium primer. Then the plaster with a primer coat of thinned paint mixed with PVA. Then a couple of coats of paint (Choose the best quality paint you can afford). I have had not had to redecorate in 15 years. If your house is airtight and not ventilated you may also suffer from condensation from bathroom and cooking. Ventilate the house in the morning and on times when heating is not operating.

10-10-20

Did this happen in an uninhabited new-build or what was the status of the house for the last number of months?

Having rust on a beading would indicate that the house was left with the windows closed and possibly with wet plaster, or that the humidity is exceptionally high during normal usage, such as in a bathroom. Most common corner beadings are galvanised, so will withstand some amount of moisture in the alkaline environment of plaster, but this breaks down over time and staining can come through where the wall is damp/cold.

Deregos.

https://www.boards.ie/discussion/2058227695/plaster-beads-rusting-and-celing-tops

What product did they come back and spray the plaster/corner beading with?

There's 3 main types of 'stain block' available in spray cans which they could've used.

water based, (not great)

oil based (okay) and

shellac based (excellent).

Sometimes I've used a combo of all three to kill a particularly bad stain but by far the most effective is the shellac based type of BIN primer. Like this https://www.screwfix.ie/p/zinsser-b-i-n-primer-sealer-stain-killer-spray-matt-white-400ml/3503H?tc=BI7&gclid=CjwKCAiA_omPBhBBEiwAcg7smZCTpVCgf5gBeg4VuGa58wfj3D8duHa-fJvb8zhrm4TrQWnCgyBQBRoCpGAQAvD_BwE&gclsrc=aw.ds

newhouse87

https://www.boards.ie/discussion/comment/118478700#Comment_118478700

Thanks for all replies, i must ask plasterer what he used, so shellac based he should have used?

newhouse87

https://www.boards.ie/discussion/comment/118467835#Comment_118467835

Newbuild, in winter so didnt leave windows open, poured new screed floor and was told not to leave windows open for few days, this results in many mold like stains on ceiling aswell. Will get heating on this week and heat recovery so hoping once i spray them again, it will all be ok.