I’m doing up a 1950s property. Had all the walls a ceilings skimmed as they were badly cracked on the joints. Excellent Plasterer and he used scrim tape on the cracks. the cracks reappeared on the ceilings as it dried. I then lightly raked out the cracks and filled with a flexible adhesive filler. Then covered with easy fill and sanded smooth. It looked good and didn’t crack. Then I applied emulsion. The cracks came back. I’m no novice and I’ve used this technique before and I’ve had excellent results previously. The idea being with flex in the joint and a thin hard shell for painting over and blending in. Any movement is taken up by the flexible filler underneath. But not this time. I’ve sanded it all down removed the easy fill and sanded the flexible filler smooth and painted that instead. This time it cracked again after a full first coat of emulsion. Took a few days but they came back. ive now opened up the cracks to about 5mm-8mm and went about 15mm deep, V cuts. Now trying to decide what to do????. Thinking about using expanding foam deep in the crack to fill it up and provide strength and bind it together and then either use a flexible filler or an easy fill to bring the surface to give me a smooth finish. I don’t want to do all of this again to end up same results. I would be grateful for anyones advice as it’s driven me to distraction!!
hmmm. Looks like it was a candidate for over boarding really, but what you could do, is undercut the plaster finish about 20mm each side of the crack by a few mm and apply easifil and push some scrim tape into the shallow, then fill flush to the existing ceiling. Btw, what paint was on the ceiling before it was plastered?
The plasterer used scrim over the crack and it still cracked. it was stipple artex. We scraped the tops off and applied the green gritted coating (forgot the name) before slimming. not sure what you mean about undercutting? any thoughts on the expanding foam at the base of the crack?
Scrape out a shallow trench for scrim. As its very likely a plasterboard ceiling, then it probably needed some screws in to tighten up the boarding first. The boarding may have been badly done originally, but its also pretty old. Either be content with filling, and probably refilling every so often, or cut your losses and over board it and reskim.
Thanks for taking the time to reply CGN. Reboarding will be my last option though as I’ve had the coving done and light fitted etc. I will try other options first. Thank you for you advice though.
It looks like you have a movement problem. Are you sure the joists are OK? If they're not up to the job, each time they flex, they will open up cracks on the ceiling below. What have you got above this ceiling?