I am cleaning up and painting a corner basement storage room. I am using Kilz mold & mildew resistant primer on both walls and floor. I have grey concrete paint that will go over the primer on the floor but would like to leave the concrete walls white.
Is it ok to just leave just the primer on the walls? The part that I’ve already completed looks fine (not too worried about appearance anyway). Just wondering if there is any reason to not cover the primer with standard paint.
Primer is actually fairly pourous to help paint adhere to it. So in theory leaving a wall just primed, increases the ability for the wall to get dirty. Other than that I can’t think of a reason not to leave just primer, but that seems fairly major.
Chemistry. Paint is designed to stabilize color (pigment) and form a smooth surface. So somewhat washable.
Keeping this simple: Primer is made of overwhelmingly resin, solvent and then a small percentage of additives for things like mold reduction or to help adhere better to a type of surface. The solvent helps the surface absorb the primer. So there are primers better for wood, cement or sheetrock. The resin is effectively what the paint is sticking too.
BTW: While I was only a Programmer/Analyst and far from a chemist, I worked for a company that manufactured Paint & Primer ingredients in the 90s.
Exactly. Think of primer like glue that bonds paint to whatever’s being painted. I know some carpenters who don’t like pre-primed millwork, doors, etc. because while they sit at the lumberyard the “gluiness” fades, either due to dust or simple chemical breakdown, so they have to sand and re-prime.
We have a room in our basement that I originally built as a bedroom for my brother-in-law many years ago when he came to live with us for a while. After he moved out the room went basically unused until my son’s girlfriend moved in with us a few years ago. She set up the room as a craft room and painted the walls with Kilz and nothing else, with the expectation that we could then easily repaint over it after they moved out. My son and his gf got their own house last year, so now the room is once again not being used (except as a storage place for junk). So basically the room has had nothing but Kilz on the walls for about 3 years or so.
The room is finished (drywall over 2x4 framing, etc) so it’s not bare concrete block, but the finish is just Kilz. You can’t really tell. The room was heavily used as a craft room when my son’s girlfriend was here, but the walls aren’t dirty.
I’ll probably paint it at some point, but it’s pretty low on my priority list. For now, Kilz works.
Kilz is very similar to old fashioned white wash. It’s primary ingredient is calcium carbonate, and then after the distillate liquids stuff like mica, talc, and titanium dioxide. It’s not going to seal very well, and the calcium carbonate can absorb moisture from the air that combination of stuff is going to create an inhospitable environment for stuff to grow on and won’t be particularly ‘sticky’ compared to most other primers. I would put some paint over it to seal the wall underneath since the Kilz doesn’t leave a cohesive layer on the material but as e_c_g has seen it will survive rather well on it’s own.
I have to confess that I’m a little confused about the idea of Kilz being “porous.” I’ve mainly used Kilz (and other sealers) because they aren’t porous. For example, ballpoint pen ink will easily bleed through most common paints, but it doesn’t bleed through Kilz.
Of course, this doesn’t mean that Kilz will seal against water. I have never used it for that purpose.
N.B.: I realize that there are many types of Kilz and many types of paints. I can only speak to the sealers and paints I’ve personally used and the circumstances for which I used them.
I bought a house with unpainted sheet rock walls in the garage. I scored an almost full 5 gallon bucket of Kilz off Craigslist for free and used it to paint the garage walls. Never painted the walls and they stayed bright and white for the next 10 years I lived there.
Ok, I haven’t noticed ball point pen bleeding through other paints. But Kilz only seals with a thin coating of heavier oils that don’t evaporate from the base liquid. It doesn’t form the kind of seal you would get from a heavier film of polymer or oil coating that comes from paint. The need for sealing is to protect the concrete walls underneath which can absorb moisture and break down over time. It also structurally helps hold the surface of the concrete together since it will be subject to changes in temperature and subject to small scale cracks and fissures. It’s critical for anyone who wants their concrete wall to maintain integrity for much more than a century, much less so for the average homeowner.
And the fact that ballpoint pen and other inks bleed through regular paint is pretty well-known. For example, contractors never use ink-based pens and markers on sheetrock precisely because it will bleed through. Pencils only.
Again…there might be pens or markers out there that don’t bleed through and there might be paints that prevent it, but I got my hand slapped at a very early point by the other trades when I didn’t use pencil.
Ball point pen ink is pretty fast drying. I’ve never seen it bleed through paint. I’m confused though, do you mean it shows through paint? Or that ink on the painted surface is penetrating the paint? Any dark mark may show through a light paint job but drywall should be primed before painting and ink marks underneath shouldn’t show through.
I painted a kids nursery/playroom once where they’d written all over the walls with various markers, pens, and who knows what else. It looked so much better when we finished for the day. When we came back on day two for the second coat, all of that stuff had bled through to the surface and it looked awful.
I was on a construction site and wrote a phone number on the sheetrock prior to painting. The GC and painter were pretty pissed. Said they’d have to seal that area prior to actually painting. The painter said it was a particular problem on raw wood. I assumed that they knew what they were talking about.
And I’ve had it happen to me. Ballpoint pen lines near a light switch came through a couple weeks after painting. I used Kilz to touch it up, painted over it, and had no further problem.
I don’t pretend to know anything about ink or how fast it dries. My knowledge doesn’t even reach the level of amateur.
When I was a new homeowner and inexperienced at these things, I tried painting a room where it was clear there’d been a desk and a pen’s ink had run a few inches down the wall.
I painted over it, and a few hours later there it was again. Three times. Then I asked around and used a rattle can of Kills. Painted that. Problem solved.
Ok, I get now that by ‘bleeding through’ you mean what I have always called ‘showing through’. I think of ‘bleeding through’ as something like wet ink bleeding through paper to something underneath it. And yes, Kilz is particularly good at covering dark marks. It uses solids that not only kill and prevent mold but are also very opaque. Not something all primers are intended for. The basic purpose of primer is to adhere to the underlying surface and provide good adhesion to a layer of paint that goes over it. Some primers and paints are much better than covering up what’s beneath it. Color can be added to primers also so that colored paint looks better and it helps hide whatever is under it.