A friend used an airless sprayer to paint the interior of his house. New drywall. He insisted he didn’t need a primer, just put on two layers of top coat. Any comments? Was he crazy?
Now it seems when you bump the walls the paint scratches pretty easily.
Any paint wizards want to share their tips on airless spraying new drywall?
Had one painter insist that we should chase the sprayer with a roller to drive the paint into the walls.
How about exterior shingles with airless. Chase sprayer with a brush? This was again suggested to me. Overkill?
Harpo
Replies
New drywall should be primed first before finish painting with one of the primer/sealer products made just for the purpose. USG First Coat and Sherwin-Williams Builders Solution come to mind, but other coatings manufacturers make competing products as well. Vinyl is the common ingredient of these coatings, which cost way less than $10/g, and they prep the surface, bridging over and sealing the dissimilar materials and textures (paper, joint compounds), and making a uniform surface for the finish paint.
Many applicators use and airless sprayer to apply, but "backroll" the wet film immediately to impart a texture to the surface. It is the drywallers that usually want to apply roller texture, because texture masks irregularities in the wall surface coming from uneven joints, lousy mud jobs, etc. There is no requirement for backrolling other than to impart a desired texture.
A top-end drywall job (class 5) can be sprayed and look great, and there will not be any adhesion failures, providing a good primer job is done first.
Go to any of the paint makers' sites and download and read the data sheets on their latex wall paints. Most all qualify their performance based on the use of a primer first on new drywall.
Unless your friend used $6/gallon wall paint to do his walls, he was not only wasting his money spraying on two coats over new gypboard, he was jeopardizing performance.
How well do those primers cover? Why, on full textured ceilings do the paint reps say it's perfectly fine to just put on 2 coats of ceiling white? Keith
Because they would rather sell you 10 gallons of ceiling white at $12/g than 5 and 5 at $8.50 and $12. Multiply that by hundreds of customers and many thousands of square feet, and we're talking real money.
Those primers are much more effective in sealing and covering that variegated surface of paper, sanded-off paper, and sanded mud. Furthermore, they provide a better surface for the first coating of finish paint over them, than the variegated surface would, allowing the coverage to be "stretched."
I have had jobs primed with USG's "First Coat," and am now specifying and using SW's "Builder's Solution," even though the SW product costs me a little more.
Both primers cover at the same rate as a wall or ceiling finish . . . 250 to 450 sf per gallon depending on surface texture.
Most any building materials yard that is stocking USG board and mud is stocking the First Coat primer, and all the SW stores have Builder's Solution.
Pretty much why we only prime with ceiling white. We've got a paint chemist in the family, that has showed us the way. Vac off the dust, damp wash everything....lay down the ceiling white(tinted to finish color if desired) One coat covers so well, you can't see the board color from the joints, then 2 coats of finish. Ever notice how with some of the commercial primers that 2 coats of finish just seems thin in spots...and dull over joints and screw holes....never happens when we prime with ceiling white.
Keith,
Have you ever sprayed shingles (shakes)?
Harpo
I'm not a painter, but I have always been told to backroll sprayed housepaint. I can't back it up with research, but it makes sense to me. The paint just has to stick better, don't you think? Especially fresh surfaces with a fine dust film.
Bob,
How do you tell drywall finish classes apart? Is there a grading system/list?
Harpo
Look here: http://www.pdca.com/standards/levels%20of%20fin%20matrix.pdf
Drywall quality goes from low to high like most everything, but when you are looking at characteristics of the finish as shown in the table we're talking about, you can quantitatively see how to choose.
I have seen drywall done on residential jobs in a lot of different housing markets, and quite a few commercial jobs too, and it seems to me that the commercial guys are a clear notch above the res guys in capability, tools and equipment used, and results.
Breaktime participants may weigh in here to agree or disagree, but I'll bet the work seen in most any Ritz Carlton beats what you will see in a McMansion somewhere.
My brother is a commercial GC and has drywall subs that give him a really top end result by skimcoating the whole thing, after everything is mudded and sanded. When you are building a new WalMart or Target, the only things flatter than the slab floors are the gypboard walls. And try doing something less than perfect when remodeling all the offices in a 400 member law firm.
Edited 3/29/2004 1:15 pm ET by Bob Dylan
Do backbrush the exterior wood shingles right after spraying. Pushes the paint into the crevices. Don't know what to tell you about the unprimed drywall :(
Handyman, painter, wood floor refinisher, property maintenance in Tulsa, OK
"If yer gonna drive fast on the highway why not go as fast as you can? Like... a hundred miles per hour or more lol."
Paint should not scratch off of the drywall reguardless of primer being used or not. Lack of backrolling didnt cause your problem either. Either the paint just hasnt cured yet, or there is a problem with the paint, or the drywall was dirty, dusty, or contaminated with something.
The walls were dusted off with an air hose then sprayed. Maybe washing down the walls might have been a better idea. He might have done one reeeaallll thick coat instead of two. I wasn't there to watch. It is certainly dry now since it was painted a year ago.
Harpo