Posts Tagged ‘stain blockers’

Mirror Tar Bleeds Through Wallpaper – Prevention

June 18, 2020



The owner of this newish home in the Woodland Heights (Houston) had her handyman remove the powder room mirror and its surrounding built-in wooden frame. Mirrors are often adhered to the wall with mastic, a tar-like substance. When the mirror comes off, some of the tar residue invariably remains.

In the top photo, you can see where removing the mirror took the blobs of mastic along with it, as well as round sections of the drywall. But there are small smudges of tar still remaining on the wall.

The problem is that tar (among a lot of other substances) will bleed through wallpaper (as well as paint, and a lot of other materials).

There are stain blockers like my beloved KILZ Original Oil Based, BIN shellac based, or others, that are designed to block these stains. But I don’t trust them. For water, rust, blood, wood sap, etc., yes. But for oil-based substances like tar, I want more assurance. The best way to prevent bleed-through is not to cover the stain, but to remove it.

So I take a Stanley knife and cut into the drywall and then peel up the top layer of drywall, taking along the offending tar residue.

So now the dangerous tar is gone. But you’re left with torn drywall. This is bad for several reasons. For one thing, you have an uneven surface that will look bad under the new wallpaper (or paint). And since the top, protective layer of drywall is gone, any moisture (such as from wallpaper paste or from latex paint) will penetrate into the torn paper layer – which will swell and cause bubbling.

All of which looks pretty bad under wallpaper or paint.

So I used the product Gardz to seal the torn drywall. It is formulated to soak into the paper; then it dries hard and acts as a sealer and moisture-blocker. It won’t block stains, but it will prevent moisture from penetrating the paper and causing bubbling.

Once that was dry, I skim-floated over the entire area with joint compound. It looks rough in the photo, but once it’s dry, I’ll sand it smooth. Then I’ll give it another coat of the penetrating sealer Gardz. See last photo. Once that is dry, I’ll cover it with a coat of Roman’s Ultra Prime Pro 977 wallpaper primer, when I prime the other walls in this powder room.

All of these various products do take a while to dry, especially the joint compound as thick as I applied it. So I went to this job site a few days before the install date, to do the initial prep, so it would have plenty of time to dry before I come back for the final prep and wallpaper hang.

DON’T Write in INK On the Walls!

January 11, 2019


Today I was prepping a room in a home in Kingwood (far northeast Houston) that was damaged during the flooding from Hurricane Harvey in 2017. Look at what some contractor did – he went and wrote on the wall in INK!

Most EVERY workman of any type knows that you NEVER write on walls with ink – nor crayon, Sharpie, lipstick, or other.

Reason being, that these substances will work their way through wallpaper (and paint, joint compound, and other substances, too). It may happen quickly, or it may take a few years, but these materials will show themselves eventually, as ghost-like stains on the wall.

Other things will cause staining, too, like blood, water, rust, oil, grease, food, wood sap (knot holes), and more.

Luckily, there are dependable stain blockers on the market that can be brushed on. I like oil-based KILZ Original, but shellac-based BIN is good, too. Water-based products don’t perform as well, no matter what the label or salesman says.

I like to be extra sure, so, when I can, as in this case, I will take a knife and cut around the stain, then dig into the drywall and remove the top layer, taking the ink with it. This way it is GONE, not just covered up.

Of course, the remaining exposed / torn drywall needs to be sealed, skimmed over, sanded smooth, and then prepped for paint or wallpaper.

But all that is worth it, when you can be assured that no stains will bleed through the finish coat.