Hey guys,
Working a remodel of a 1940s house with button board backed plaster walls. There are some decent size cracks in the plaster at the usual places you’d expect. My painter simply spread topping compound over the joints, and less than 3 months later, the cracks are back. Any suggestions for a longer term fix? Fiberglass koint tape perhaps?
Thanks!
Replies
The small cracks are the hardest to remedy. I usually use mesh tape. This is stronger than using paper. You do have to add numerous coats to cover and taper. Only use the topper joint compound as the last coat. This stuff has no strength.
I also use a halogen light shining down the wall to make sure the patch is invisible.
The larger cracks are easier. I pack them with "Durabond" setting compound. This usually is stronger than the original plaster. Then top coat with Lightwieght and then topper.
I'm a sKeptic about quick fixes. Did see a "Crack fill in a Can" You spray it on the crack and then paint. I used this on a ceiling once. Hard to tell if it worked since I covered it with a knock down.
Here's how I do it... done hundreds of cracks this way, only seen a few come back (typically due to "framing that moves", i.e. studs that aren't nailed, etc):
1. Scrape out crack really well with sharp utility knife (be careful...)
2. Mix up Durabond 20, 45, or 90 whichever is available and suits your working time
3. Use a squirt bottle to wet the crack down (keeps the moisture from being sucked out of the Durabond, which weakens the repair).
4. Apply Durabond and embed either fiberglass joint tape, or fiberglass window screen in the mud. Usually I use the later, apply the Durabond, and before applying the 2nd coat (1st coat is pretty well set), trim the screen to size with a utility knife.
5. Let set up, wet sponge and scrape any areas that are high with a putty knife (i.e. if you were sloppy with the 1st coat), reapply a 2nd coat. Using 45, you can usually do this within an hour of your first application... do it when the first coat is pretty much hard, but will still appear wet. Repeat this step as needed.
6. After final coat (which should be slightly proud of surrounding area) let sit overnight, then do your final sanding, prime with oil-based primer.
If you skip step 1 (opening the crack up big enough) or using topping compound (which was a mistake I made in the past...), you will see your crack back in no time. Do this approach, you should be happy with the results.
Ditto the halogen light recommendation... it helps any imperfections stand out.
Thanks guys, I love the assistance and help in these forums!
A lot depends on how much the framing moves with the seasons. Sometimes it's best to just use a flexible caulk, since no plaster is strong enough to resist framing movement.