New drywall prep before painting?

[Henry W]

Great timing on the new DIY Home Improvement board.

I am nearing that step in the basement renovation (carving out a bedroom from a larger basement room) where I will prime and paint the walls. This is all new drywall, and I have used two different types. On one wall I have the normal very smooth drywall. In the rest of the room the mold resistant drywall sheets have slightly more texture on the surface.

I am concerned that the relatively smooth mud on the joints and holes is going to be a texture contrast to the somewhat rougher and more textured bare board (the mold resistant stuff). In other cases (upstairs, on existing walls) where I have completed a hole patch before painting I do see this sort of texture contrast: the patch sticks out under the 'right' glancing light. It seems like once the wall is primed, it is too late to do anything about this texture contrast.

Am I making any sense? What to do? Can I prevent this texture contrast, or am I being anal?

Thanks, Henry

 

[Ray Martin]

Henry,

There are probably two parts to the differences you see in sheet rock walls that have been painted. Light not only reflects off the surface of the paint, some of it goes a bit deeper and bounces back out. There are different amounts of reflection from the parts where you just have the paper of the sheet rock and the parts that have mud (joint compound) lines and spots.

I'd put on a coat of (good quality) primer / sealer on the new walls so that all parts of the wall will absorb paint an reflect light the same. If the different types of sheet rock have different texture or tooth, you might be able to even them up with textured paint. (I have to defer to the folks here who have been professional painters for this part).

Types and placement of lighting will also have a significant impact.

Ray

 

[alleng]

you could look into a knockdown finish, where loose mud is sprayed on the wall,and after it sets a little they go over it with a trowel; giving it a good looking textured finish. they use loose drywall mud and spray it with the same sprayer that they apply acoustic sprayed celings with. when done right,these walls look pretty good,imo

 

[Glennbear]

Based on personal experience I would definitely not recommend adding an applied texture in an effort to achieve uniformity textured walls are h--- to repair or repaint. In my last house I had applied "sand paint" because of surface irregularities and hated repainting that particular bathroom evermore. I believe using a flat paint on all walls would reduce light reflection which shows up surface variation.

 

[Ray Martin]

Based on personal experience I would definitely not recommend adding an applied texture in an effort to achieve uniformity textured walls are h--- to repair or repaint. In my last house I had applied "sand paint" because of surface irregularities and hated repainting that particular bathroom evermore. I believe using a flat paint on all walls would reduce light reflection which shows up surface variation.

Glenn,

Good point. Your post just made me think of all the trouble I've had with popcorn ceilings.

Ray

 

[Gotcha6]

Semi gloss paint will do this on any drywall. Use a good grade of washable flat. Stay away from eggshell finish unless you know the wall won't be subject to abuse or patching. Sand the dryall sparingly on the paper. It has a tendency to knap up the paper & leave a rough finish. USG used to make a product called 'First Coat' primer that would even the texture of drywall. Find it if you can. Avoid end butt joints in the drywall. If your ceiling is >8' use 54" board laid down or stand up 4x boards. Good luck!

 

[Gotcha6]

Two other things to add;
1. If you use quick setting compound, always skim over it with regular mud to avoid paint flash. This is where the quick setting mud sucks up the paint and leaves a dull finish on the joint.
2. Paint with a 'clean' roller. Wrap the roller in masking tape & then pull it off to remove any loose nap. It'll keep the fuzz outa the finish.

 

[SteveColes]

Besides all of the good advice that you have been given add one that is only for the really anal retentive. Put a skim coat of joint compound on the walls and sand smooth:swoon:, then apply the sealer coat. I have done this in past and works great, but I'd never do it again, it is too much work for lazy me.

You might get away with only skim coating the rougher walls.:widea:

 

[Gotcha6]

Steve, are you into self punishment in some way? LOL We tried that in commercial work (medical/office) & found it was cheaper & got a better job to glue & screw 1/4" drywall to the old & do jamb extensions. Very few people have an eye good enough to do skim coating straight anymore. It takes the skill of a plasterer. I'm sure you know this already.

 

[DaveD]

I'd skim coat it. Thin the drywall mix a little and put it on with a paint roller and use a wide drywall knife to skim it off. The wider the knife the better. Then maybe a quick sanding of the wall depending on how well you skim.

Be sure to prime the whole wall with a good drywall primer. The primer will seal the wall so the wallboard and where the compound is don't soak up the paint at a different rate (which makes the compounded areas stand out).

You should be able to skim the wall after its primed (if you primed it already). If you skim it then prime it again.

 

[Steve W]

Henry,

The whole solution depends on what you really want for a paint finish and how anal-retentive you are.:lol:

IMHO, if you use anything glossier than flat paint, you will never get 100% undetectable joints and filled holes using the "traditional" method of drywall installation -- even with the older, cardboard material. Steve's suggestion of skim-coating the entire surface does work but it is more time consuming. You only need the thinnest of coatings. Myself, I've never had that much patience and will either call the plasterer (in which case, you should be using blueboard -- if it's available around here) or go with flat paint.

I have seen walls that friends of mine have skim-coated with mud and then painted and they came out great! There will be little imperfections across the whole surface, but these will mimic old plaster pretty darn well. Having a look of an older-style plaster job is an asset to me but I understand that not everyone shares that opinion.

Steve

 

[Cuprousworks]

I recommend using PVA Primer/Sealer. It's got more body than the usual drywall primer, the thicker coat helps with different underlying textures. I applied it very heavy - 1 gal per 400 sq ft - and unlike the other thinner primers the coat was completely opaque.

Although I didn't use MR, I did just complete my shop walls with Satin finish paint, and there was no underlying texture visible. Good news is that it isn't really any more expensive.

Mike

 

[SteveColes]

Steve, are you into self punishment in some way? LOL We tried that in commercial work (medical/office) & found it was cheaper & got a better job to glue & screw 1/4" drywall to the old & do jamb extensions. Very few people have an eye good enough to do skim coating straight anymore. It takes the skill of a plasterer. I'm sure you know this already.

My skim coat was lousy, but that's why they sell sandpaper:twitcy:

 

[Steve W]

Oh, yeah -- sandpaper is definitely a factor!:-D