Clean new skim before painting?

[philipb82]

Hello, we had a wall skimmed about 2/3 weeks and plan to paint it soon. Is it necessary to sugar soap it before painting? Phil

 

[TheDec]

No, No, No.

Never apply sugar soap to unpainted plaster skim.

Dec.

 

[Richard C]

& don't use PVA either. Just dust it off & mist coat with thinned (25-30%) ordinary matt white emulsion; apply 2/3 coats in quick sucession, leave overnight & then apply your chosen finish.

 

[Sharpey]

A quick question as I'm about to do the same.

Can I give certain areas of the new plaster a light sand with fine sandpaper to remove imperfections?

How quick should the mist coats go on after each other?

B&Q have got small tubs of their cheap and nasty matt emulsion for ceilings going half price, could I use that for the mist and my Crown matt for the topcoat?

Thanks.

 

[Richard C]

Can I give certain areas of the new plaster a light sand with fine sandpaper to remove imperfections?

Light sanding & for any filler used to hide trowel marks etc; although there shouldn’t be many or indeed any if the spread was any good. What you should not do is use heavy sanding to clean up a botched job, this will expose the plaster grain under the surface & it’ll look like suede brushed the wrong way when you paint it requiring more coats to cover it up.

How quick should the mist coats go on after each other?

apply 2/3 coats in quick succession, leave overnight & then apply your chosen finish.

Don’t wait between the mist coats.

B&Q have got small tubs of their cheap and nasty matt emulsion for ceilings going half price, could I use that for the mist and my Crown matt for the topcoat?

I only ever use cheap own brand matt white for mist coats.

 

[Sharpey]

Thanks a bunch Richard C....just as I assumed. I am aware of plaster getting roughed up if the sandpaper/application is wrong, I messed up on this last time.

One of the ceilings has a patch repair and the plasterer has overlapped a fair bit on to the old plaster (over the join). The edges are quite rough and will need a scrape and sand to try and blend it in with the old plaster....would that be the correct process? As in, carefully scrape off the residual mess, light sand to try and blend the edges down to the old plaster and if there is still a tiny gap maybe use a fine filler on the edges? I'm not expecting perfection but obviously I want it to look as good as possible especially as the ceiling is low.

I hope that makes sense, I can take a picture if not.

 

[Paintmate]

One of the ceilings has a patch repair and the plasterer has overlapped a fair bit on to the old plaster (over the join). The edges are quite rough and will need a scrape and sand to try and blend it in with the old plaster....would that be the correct process?

Yes . just sand down to a fine edge anywhere and the paint will do the rest. The new plaster will be very thin at the edges and sometimes the use of a roller will "suck" the new plaster off. I usually brush paint these fine new plaster edges.

 

[Richard C]

If finishing plaster has been used to feather in the join (which can be difficult unless you really do know how) it contains very fine lumps of grit when compared to filler; it’s a part of its natural constituency. If "blending" has not been done successfully “off the trowel”, sanding will only expose this grit in a sort of never ending process which means you will always see the join. You will be better to fill away from the new plaster with Easyfill to blend & sand into the surrounding existing plaster rather than the other way around; get it right at this stage & all it will need is a couple extra coats.

 

[Sharpey]

Paintmate and Richard C - thanks for the tips, much appreciated.

As far as using the roller over it, it's a chance I will have to take as the ceiling is large and I will have to try and keep a wet edge. It hasn't been touched in weeks so should be fully dry.