Hi All

I'm new to all this so please forgive me if I'm asking stupid questions....

I had a doorway blocked up with brick on outside, insulation and then thermolite blocks on inside, within a recess below the concrete lintel.

I have now fastened 12.5 mm plasterboard to the thermolite blocks using dry wall adhesive, but need to fill in the gaps around the edge of the plasterboard to the plastered wall in the recess. (I cut too much off the plasterboard in places as the side walls of the recess are not completely vertical.)

a) As I will just be painting the plasterboard, what should I use to fill in the gaps, to get a smooth finish, please?

Is decorators caulk a good idea or could you suggest easier for a novice to use?

b) When painting the plasterboard, I presume I could use either plaster sealer or watered down paint before using normal emulsion paint - or would the paper balloon outwards and not dry back flat?



Thanks in advance for your advice!

CThatcham.

Fill the gap using bonding plaster and then smooth ofer the bonding plaster with easifill. You may find that the joins between the different finishes crack along the length. If I were doing it, I would skim the whole wall once it was all roughly level and use reinforcing (scrim) tape along the joins to prevent the cracks from appearing.

Hi Jozeffo

Thanks for your suggestion, however I've never plastered anything and am trying to make things easy, quick and less likely to go wrong.

Is there any reason why decorators caulk or similar wouldn't work?

Is there any reason why I can't just seal the plasterboard and paint it?

Please advise, thanks.

cthatcham

If you want a decent finish, you will need one that is easy to sand. Bonding plaster will provide strength and can go on thick to fill up the gap, ideally just shy of the surface. Then use a easifill to smooth over the surface, sanding back to smooth finish. You don't need to be a plasterer to use bonding plaster to fill the gap, you just need to add dilute pva to the gap first and leave for ten minutes to go tacky so that the plaster doesnt dry too fast and end up weak. Not a difficult job.

Decorators caulk cannot be sanded. even if you smooth it perfectly, the joints will always be visible. Caulk is for use in seams. On a flat surface, polyfilla would have been used until easifill became prevalent because easifill is really easy to sand to a perfect finish. Polyfilla and other cement based fillers are not.

You can paint directly onto the plasterboard provided it is dry.

Thanks for that, Jozeffo. I'll definitely have a go with the bonding plaster, etc.; I know I'd need to sand it !
I think hardware stores enjoy fobbing me off with duff advice, just because I'm clueless!

Many of the hardware stores aren't exactly clued up. My local diy store is very good, but they only really learn about up to date stuff like easifill because they have some good trade customers who know what they want and they listen.

Some local stores offer stock and advice that was current twenty years ago. Others are excellent and a welcome respite from the major sheds.