Sealing Plasterboard

Hi Folks

I`m replacing the ceiling in my Dads spare room .

To save on cost , I`m hoping to do it without skimming the plasterbord .

Two questions . First , if I use the bevel edge boards , whats the best way to fill the gaps to obtain a smoooth joint , and what is the best filler ?

Secondly , I`ll use either an emulsion to finish , or lining paper . Whats the best way to seal the borads prior to finishing . Do I use a PVA , or will a mist coat of emulsion suffice .

Thanks .

Easifill and tape for the joints - have a look at British Gypsum site - loads of details there. NO to PVA never.

ref: Nige F above correct Then you can coat the plasterboard with Zinsser Gardz, with a roller or brush(it feels like painting milk) once dry apply your topcoat paint x 2 coats

Again, I would follow NigeF's advice.

I have only used taper edged boards once before. After filling and sanding the joins, I just used a dilute coat of Dulux Trade matt white followed by two full fat coats of the same emulsion.

Guardz is a great product and great when dealing with problem substrates but dilute emulsion should suffice.

PVA- should NEVER be used prior to either painting or tiling. It is great for plastering but SHOULD NEVER be used over finished coats of plaster. New plaster about to be painted, thin the paint as per the manufacturer's advice. Tiling, use SBR or a dedicated acrylic sealant. PVA under paint is a mare, it will either blister or the paint will take hours to dry. A thinned coat of emulsion will accept the next coat after a couple of hours, try rolling over a PVA'd surface that quickly and you will effectively find the roller slurps away the coat you applied previously. Sorry, I appreciate that the likes of YouTube are awash with people inappropriately recommending PVA but those people are muppets.

As an aside, the site where I have been working, the tilers went straight over the new plaster with the cement based tile adhesive. I didn't want to be the person that grassed them up but I don't want to be the decorator that was aware that the shower area had not been sealed which could result in a whole load of pain for the customer further down the line, so yeah, I grassed them up. The main contractor wasn't on site at the time, someone, ie me had to cover the client. The tilers' response- "Yeah but no yeah, it should be fine, we all do it at some point". Sorry- I have gone off at a tangent- I was trying to provide an example of supposed tradesmen, including those found on YouTube who are clearly not particularly bright. I am a decorator, I know that cement based tile adhesive that is applied directly to gypsum based finishes suffers from the formation of etteringite crystals. Why on earth do people who tile for a living not know that?

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