I'm wrong---concrete dust, not mildew

[Denise Ohio]

So I was totally wrong. What I thought was mildew turns out to be concrete dust. My carpenter confessed that he had sunk a couple screws into the concrete floor. He blew the dust out of the holes, but hadn't vacuumed up the mess and the dust settled on the sidelights of our brand new, raw Doug fir sidelights.

Then it snowed, then rained, and the concrete dust appears to have stained the bottoms of the raw wood sidelights.

I tried a series of things in a small area to see if I could lift out the stain, but nothing worked. I'm thinking the only way to get rid of the stain is to start sanding and don't stop. Ever.

I'm considering painting the whole thing, but I'd like to explore a stain/sealer combination.

Right now the staining is in the lower part of the sidelights. I'm thinking I could sand to 220, condition, apply a dark reddish-brown stain, then use a marine sealer (Waterlox, perhaps).

Any suggestions for products or techniques? I'll do some samples, but I'm concerned about blotchiness.

Thanks.

[Jim Becker]

It seems to me that the contractor has some skin in this game...your door is damaged because that dust from drilling was not properly cleaned up. IMHO, he owes you a brand new door.

[Rich Engelhardt]

Hello,
It may be beyond restoring, and as Jim said, the carpenter may be on the hook for a new door.

[Denise Ohio]

Well, I'm not dinging the carpenter for this. He's a good guy. He's made a total of two mistakes including this in the many many weeks he's been working for us and has saved me from myself numerous times.

He has stayed late for several days, saying he's just tidying up, but I can hear him working on his own time. I know he feels terrible about the sidelights and this is his way of making up for his brain disengagement.

I shouldn't have installed the door and sidelights without a finish, period. That was my mistake. Dumb dumb dumb. I know better.

Can I prime and paint? Or is it destined for the burn pile? The door itself is okay, but the bottom of the right sidelight in particular is...well, it's messed up. I'd take a picture, but I still feel a tiny little bit of heartbreak every time I look at it.

My plan is to uninstall the sidelights and jamb and take the whole thing into storage. I'll frame a temp door and sidelight in the opening to keep out the crackheads (technically, methheads, but either way...) and get some heat inside the house.

If I can prime and paint, I will. If not, then boo hoo.

Thanks for your help, guys. I appreciate it.

[Rob Amadon]

Well, I'm not dinging the carpenter for this. He's a good guy. He's made a total of two mistakes including this in the many many weeks he's been working for us and has saved me from myself numerous times.

That is so refreshing to hear someone say that. If the carpenter was a hack and screwed up then, yeah, make him pay for it. But you have found a good, responsible guy, and you don't want to make him pay for a mistake, even though he should have known better. If more people would deal with each other in such a reasonable manner we would live in a much better world.

Rob :)

[Jim Becker]

Given your description of the contractor, I take back my previous recommendation.

I suspect that you can seal the door with BullsEye and paint.

[Rich Engelhardt]

Hello,

Can I prime and paint?
Yes.
Neutralize the affected area first with an acid wash.
Regular vinegar should be sufficient.
Sponge on the vinegar - let it sit - it may bubble as the acid/base react.
Flush with clear water. Dry with rags.

Stop by a swimming pool supplier and pick up an inexpensive pool testing kit ~ $5 or $6.
When the surface had dried completely, rewet it and test the pH.

Repeat the vinegar wash/water rinse as needed to bring the pH into the "normal" range.

Concrete dust is extremely caustic. It has a higher pH than lye (Drano).
{15 vs 13}. Caustics attack the cell structure of organic material (like hair and wood).


I tried a series of things in a small area to see if I could lift out the stain,
Can you provide a few specifics as to what you tried?
If you treated the stains as mildew, then in all likely hood, you used materials which were on the high end (akaline) of the pH scale.
Things like bleach, soap & water, etc.

Once the pH is near neutral (~ 7), then the surface can be primed and painted like any other wood surface. The pool test kit will have a little color scale that you compare the litmus strip to to determine the level of what you're testing.

Jim,

I suspect that you can seal the door with BullsEye and paint.

The vinyl based Bullesye 1*2*3 would work, but the "other" Bulleseye - the B*I*N pigmented shellac would excite the problem. Shellac is on the acid side. It would always have problematic adhesion issues with a surface high in pH through the formation of salts.
On Zinsser's website they specify using the Bulleye 1*2*3 on possibly high pH surfaces.

I'd bascily treat the condition of the wood the same as fresh plaster.
Once neutralized though, the surface could safely be covered with the pigmented shellac.

[Jim Becker]

Thanks for the extra information, Rich. Good to know!

[Denise Ohio]

Rich Englehart, this is exactly what I needed to know. Thank you. Naturally, I have more questions...

1. My plan is to uninstall the sidelights and put everything into storage. Can I wait to vinegar or should I do it now?

2. I was thinking if I added on some exterior benches attached to the sidelights, I could hide the ugliest of the stains, plus protect the door and sidelights somewhat from driving rain. As long as I protect the wood by neutralizing properly, is this a clever, workable idea or just another crazy-ass whim on my part?

3. As far as what I tried...tiny little spots of mildew killer (smells like bleach), sanding, a bit of alcohol (not vodka, though I was tempted), and mineral spirits. These were dime-sized spots, other than the sanding, which was bigger and way down low.

Jim, no worries re: hackerdom. I'd recommend this guy for just about anything.

[Bonnie Campbell]

Everyone has a brain fart at times. Sounds like a good carpenter since he was willing to admit his mistake.

A carpenter friend of ours put up a wrap around screened porch on a house. He'd gotten it all done when he told me how he was going to spray the wood with sealer (NOT covering the screen with anything). I pointed out to him he might want to get his paint brush to use since any over spray was going to clog the screen :rolleyes: ...........Normally the guy is pretty smart......

[Rich Engelhardt]

Hello Denise,
I'd neutralize the surface as soon as possible.
Letting it sit for any length of time may cause damage to the cell structure of the wood.
It's especially important if the midewcide you used was bleach based - which it probably was/is (most of them are). The bleach will add to the alkalinity.
At this point it sounds like the only damage is cosmetic. Letting the wood sit in this state for any length of time may result in a weakening of the cell structure of the wood.

[Denise Ohio]

Okey-dokey.

I got my pH strips and vinegar. It's pretty cold today (it was snowing a few minutes ago) but it feels like it may warm up just enough.

After lunch, I will intrepidly blot vinegar, wash, test, and repeat as needed until I get to my target pH of 7.

Thanks for your help.