Patchiness caused by lap marks on ceiling-can it be sanded?

[Sharpey]

Hello all. I am in the process of painting a large ceiling. It has been painted several times and from particular angles lap marks or some sort of patchiness is visible.

After much faffing and research, I think what the problem may be is old lap marks have slightly changed the texture of the finish in certain spots, and when light is reflecting from it it causes the patchiness that is seen from certain angles. I initially thought it was painting technique, or poor quality paint/equipment but I've tried several methods now and have yet to achieve a uniform finish. For the record, I have recently painted almost an entire house worth of ceilings recently and haven't experienced the same problems.

It could just be the placebo effect, but when I look closely at the patchy parts it does appear to be ever so slightly thicker/rougher than the non-patchy parts.

My question is, is this a recognised problem, and if so, can I sand down these parts and paint over them again? I have got some fine grade sandpaper that might be suitable and a pole sander - or is sanding likely to make the problem even worse? This is the last resort for me otherwise I will just accept defeat and leave the ceiling as is.

Thank you for any help.

 

[TheDec]

The lap marks of which you describe are more than likely the cause of fresh paint being applied over a drying edge, or uneven application.The only real way to obliterate these is by sanding, take your pole sander and give the ceiling a good sand back and if your choosen grade of paper is proving difficult then lower the grade. If you need anymore advice on this let us know and dont give up, dont forget eye and mouth protection whilst sanding.

Dec

 

[Sharpey]

Thanks TheDec. Yeah, that is almost certainly what caused it. Originally I used a small roller and took too long painting it. I seem to have got my technique down now and am also using better rollers and paint as well. However this problem ceiling remains.

If I've understood you right, you think I should sand the whole ceiling back, not just the marks? That would make sense but the ceiling is very big so obviously I want to avoid doing it unless it is absolutely necessary. Also, how far do you think I should sand it? I used a 320 grade paper, this removed the texturing and flattened out the marks, but paint remained.....is this sufficient or should I be actually looking to strip paint (don't think I should be but may as well ask)?

Thanks again for the reply BTW.

 

[joe-90]

It sounds to me like plastering fault usually referred to as 'suede'. The fault is in the plaster not being polished correctly. Your best bet is to sand it with a fine grit paper.

 

[TheDec]

There is no need to remove the paint just flatten and feather out the raised areas, if these are random then there is no need to sand the entire ceiling only the affected areas. Also if your happy that the 320 is getting the job done fine but dont be afraid to lower it if the need arises. See how you go and let us know how you get on and a pic or two if possible would help.

Dec

 

[Sharpey]

Thanks again, i'll give this a go. I'll try to get a pic up but it's hard on my cheap camera, just looks like a white blob!

 

[tommytempra]

Hanging lining paper would solve the problem

 

[Sharpey]

I was thinking of that Tommy. It would give me a blank canvas. Thing is, it would have be hung perfectly for it to be effective, as you wouldn't want to see the joins. It's a bit risky really because if you're not happy with it when its up there isn't much you can do from that point on.

 

[joe-90]

Just stop looking up and forget about it. Life's too short.

 

[Sharpey]

I'm at that stage joe, going to sand it, paint it, one last shot and that's it.

 

[patagonia]

As a matter of interest, what paint were you using? We are experiencing similar problems with the ceiling of a large first floor study which has sloping sides and an open staircase coming up in the middle, so a bit awkward to do. It was done by a decorator a few weeks ago, using Dulux Trade Vinyl Matt, and looked very patchy/stripey, with some bits looking very thick and others missed. I could see as he rolled it on that he wasn't joining on to the wet edges, missing bits in the middle. So we had it done by someone else, again using Dulux Trade Vinyl Matt which cost me £29.99 from Homebase, and to my horror it looks worse than before. He says he put 2 coats on (only here for the morning) and has used the whole 5 litres but you can see stripes where some bits have a sheen on them and others don't. I wonder if he didn't stir the paint properly at the start, which the tin says must be done. He says he didn't thin it; the tin says you shouldn't. It wasn't like this before we had it redecorated, just rather dirty, so it can't be anything to do with the plastering which looks pretty good to me. There were no cracks in it and it feels quite flat.

Someone was trying to tell me that the Dulux Trade paint bought from the sheds is not the same quality as that bought from their own shops but surely if they call it trade paint for professional use, it has to be, hasn't it?

Has anyone else had problems with Dulux paint recently? I must say I am not impressed with their Walls & Ceilings Matt Emulsion which has been used on the walls during this redecoration. It doesn't look a solid colour and though it claims to be wipeable, it comes off onto a damp cloth. I feel sure we will have to redo it before long, even if we ignore the stripey walls for now.

What is the best paint to use these days?

 

[TheDec]

The problem is'nt the choice of paint it's overthinning and bad application, the decorator of whom you employed was a chancer. the only cure for your problem is to sand back and remove the lines that were left from incorrect use of the roller, the application of further coats will neither hide or mask bad application.

Dec