concrete hell #1

I forget how much I’ve posted about the back bedroom remodeling project, but that has been going along well enough. We got someone to stucco the windows (and passed all the related inspections), then we put up the drywall (using Georgia-Pacific DensArmor Plus wallboard — basically drywall but with fiberglass matting on both sides instead of paper. If it gets wet, no mold!). We had a great crew come out to tape and texture the drywall — they did a beautiful job on the new drywall, as well as on the existing (ceiling and interior wall) drywall. We painted it with Frazee Envirokote Zero VOC paint (which really is zero VOC — the office is getting painted by pros at the same time, and the difference in the odor — or lack thereof, with the Envirokote — is amazing). Then, since it hangs on the wall and doesn’t sit on the floor, we got Elfa shelving from the Container Store (during the annual Elfa sale, no less!) for the closet and along one wall for bookshelves.

We even get and install a dog door (with wall tunnel) to put in the wall so the dog doesn’t have to ask all the time to go in and out. And we’re in the process of getting the outside of the house painted and stucco-color-coated.

Feeling pretty confident (finally) about the whole project, I start cleaning the floor to prep for gluing down the bamboo flooring planks that we purchased for this room three (!) years ago, when we first started this project.

After cleaning the construction (concrete, drywall, etc.) dust from the surface, I seal the holes from where the carpet tack strips were laid down, as well as a chunk that was taken out of the floor for some weird reason, that we thought was a hole under the carpet when we first bought the house.

I start looking into how to glue down these planks; when we first bought them, we were told by the flooring seller that we should have a moisture barrier between the planks and the concrete slab, and that using vinyl flooring upside-down should be fine.

I do research, and more research, and find that either this or some kind of concrete sealer should be fine. I double check with the flooring seller again, and they recommend using Bostik’s Best for the glue and Bostik’s MVP as a sealant.

However, reading even more into this, I find that if there’s anything other than bare concrete on the floor, we’ll have to scarify (grind away the top layer of) the concrete before applying anything, otherwise it won’t stick. The problem that arises is that there were asbestos tiles on the floor when this whole thing started. The abatement company removed the tiles, scraped the floor, then sealed it with an asbestos fiber containment sealer.

I have visions of having to call the asbestos abatement company out again, and paying another few thousand dollars for them to scarify the concrete slab with their containment units. Then, after talking things over with my SO, we realize that we can just use a floating wood floor instead.

So we look into and find a lock-together, glueless floating bamboo wood floor, and order a single box of it to see how well it works.

It arrives, looks like it’ll work well, and so we buy four rolls of floating-floor underlayment.

Then, the rainy season starts. (These are the California once-every-seven-years monsoon heavy duty style rains, of course.)

As usual, I’m apprehensive — it’s only been a year since we had the nasty roof leak that started all this crap, and even though the entire roof is new and we have a ten year warranty (at least), I still worry about leaks.

Fortunately, the roof doesn’t leak. We have a small pond out back due to a broken gutter drainpipe, which I have to keep drained using a small fountain pump and a network of small trenches (I did always like playing with water and trenches, but this is getting ridiculous).


And other than a couple of slightly leaky old aluminum windows (on our list to be replaced anyway), nothing major seems to be wrong.

Except, of course, that we seem to have white crystals growing up from the concrete slab along the outside walls of this room.


Not knowing much about concrete, other than that it’s porous and that you don’t want to get stuck in traffic in a cement truck with a full load, I start trying to figure out what this stuff is. “white crystals growing concrete slab” doesn’t seem to bring much from google except for one useless reference to “alkali bloom” on a floor installer FAQ — it says it’s bad, but not what it is or what to do about it.

Finally I figure out that this phenomenon is called efflorescence, and that normally it shows up as a white stain on masonry work. It’s salt that’s carried through the pores in the concrete or mortar or bricks by moisture and/or water. Except to be getting these huge crystals, I’m guessing that we’re getting a lot of moisture coming up through the slab.

Hoping that this is a temporary thing, I scrape the crystals away and wipe the floor. But they come back in a few days.

So, we fixed the moisture problem coming from *above*; now we have an issue coming up from below. Eeee.