painting advice

number twelve

im painting my living room white. i'm using a roller to put the paint on but i find this leaves a kind of pattern on the wall, i went over it with a brush whilst it was still wet but this just changed the pattern to a stripy brush stroke pattern. i was thinking of giving it a little sand with fine sand paper before i add my final coat and then do the same once finished. would this be a good or bad idea or am i just looking for perfection and wasting my time.
thanks

Wertz

Are you using matt emulsion? If so that's your first problem, particularly if it's chaep stuff. Matt will show roller and brush marks as it is a heavy bodied paint that dries to a soft finish. You are perhaps applying it too thickly...try adding 10-15% water....or you may be putting the actual paint on too heavily or with the incorrect type of roller/brush. Your technique for rolling may be leaving tramlines (lines from either side of the roller sleeve), you could have far too much paint on the roller and not be evening it out correctly.

Sanding between coats is de rigeur with any paint, matt is no exception. But sanding after a finish coat? You're going to leave scratches, swirls, dusty blemishes...all much worse than any "pattern" you're leaving now.

If it is matt you're using, then try using a soft sheen, acrylic eggshell or a washable matt...all of these dry to a flattened/sheened finish. Before you do this, you should give all the previous coat a light sanding, otherwise the underlying "patterns" will just show through the new coat(s).

Looking for perfection certainly isn't wasting your time...it's your home and you want it to look good. However, it's pointless being obsessive about it....paint is not a perfect substance.

number twelve

cheers, yes i am using matt paint and yes it is the cheap stuff. my thinking was to put some cheap so called trade paint on first as an undercoat and then to spend the money on some good quality washable matt (i dont want a silky finish).
you may be able to help me with an other problem i am having. water marks on the ceiling, i painted over them but they re appeared not long after, they have been checked with a moisture machine when i was buying the house and i was told they were bone dry. any advice

Wertz

Ok first the walls and white...if you're intent on overcoating with washable matt (buy a quality brand!) but first give the walls a good sanding, in a random pattern with mid grade (~180 grit) sand paper/pad and apply the top coat spraingly. For the final coat (you will stiull need 2, regardless of the white underneath) ensure to keep a wet edge on your paint...that is, taking a wall/area at a time, cut it all out by brush then roll in tight to the brushing whilst it is still wet...this way it will all dry in together and will avoid patchiness.

As for your watermarks, common problem. You can either apply a proprietary stain blocker to the area or you can touch up the marks in oil based eggshell/gloss (allowing to dry fully) and then overcoat with your finish. The stain blocker dries faster and allows you to get on with it, but you may have some old oil finish hanging around and this will save paying 20 quid for a litre of stain blocker.
These marks are not damp itself, but rather the remains of some sort of fungal/mildew growth that will continue to stain and bleed through water based emulsions.