Gyprock question

[redheeler]

Hi All
My first post on this informative forum. I have a question regarding plasterboard. Having finished installing gyprock to masonry walls the moment of truth has arrived - taping and finishing joins . The sheets all seem quite flush apart from one area - the top sheet is proud by about 5mm along horizontal join. Is it possible to scrape back edge of plasterboard before taping or will rebate on board accomodate this ? I hope someone can decipher my convoluted question.

Thanks
Redheeler

[mic-d]

Welcome redheeler, oh dear, that does seem a big difference in heights which I don't think will be accommodated by the recessed edge. I would use a longish straight edge to 'screed' a wide coat of base coat across the area and then repeat with a wider coat of top coat. You could use just top coat but it will probably mud-crack because of the depth of the repair. I wouldn't carve any of the board away. goodluck

Cheers
Michael

[rod@plasterbrok]

That is how to do it. Except I would tape the join 1st then use either base coat or cornice adhesive to fill out with a rough coat, use a 4 ft level like a trowel. This 1st screed will be very rough don't bother trying to get it right. Then scrape back the roughest spots.

Use the level to see where you need to increase the amount of fill and do that again using the level again to screed it off.

Repeat the scraping back.

You should have a reasonably flat join but still a bit rough. Use a 12 inch blade or trowel and apply a thin coat to fill any small indentations etc. If you find you have any high spots scrape them flat. All scraping should be done once the plaster has set but not dry.

Now you can apply a final coat of top coat. Because the join will be quite wide it is best to apply working across the join 1st then finish by troweling along the join.

Don't worry about the trowel marks so much as they will sand out. At the worst you may need to give it another skim of top coat.

Plaster, when applied thick like this, needs to be built up in a series of layers, each one being thinner than the previous layer. The most important point is that you don't have high spots between coats. If you run over the dry join with a level any high spots will have a black mark from the metal on the level. Scape those spots back.

It is very hard to fill a bump!!

Good luck with it.

Rod

[myla]

hello,

dont know how big an area, but I would screed first to same level of rebate of abutting sheet (approximately)

feather out, make smooth to look good

then treat joint as normall with mesh etc

screed in several coats allowing to dry

find if running straight edge over wall will damage mesh or paper as that area is your guide

you have built up then treated

thankyou

myla

[redheeler]

Thanks Rod, Michael and Myla for advice. I was thinking of removing the sheet and re-doing however you have given me some hope.

Rod, Plasterbrokers website has been invaluable as have your previous posts.

Thanks again all.