Repairing Cracks in a Lath and Plaster Ceiling

Progress continues in the smallest bedroom! It’s been a pretty hectic month so far, so progress is far less than I would have liked. But non-the-less, we are making some progress and this week I tackled the cracked ceiling.

When we renovated the bathroom, we chose to pull the entire ceiling down. It was horrendous. Seriously horrendous. Let me just give you a little reminder…

Ohmygod it was horrible. It took two days to pull down and about a month to remove every inch of dust that had consumed the entire upstairs! But pulling down the ceiling was kind of necessary – not just for dealing with the cracks but it also allowed us to fit the in-line extractor fan without creating a crawl hole in the attic room, which would have been equally as bad in a room we didn’t yet want to renovate.

This time around, I was desperate to create as little dust as possible. The problem with lath and plaster ceilings is that they’re super liable to cracking. This causes movement between the plaster and laths as the plaster begins to pull away, which can eventually lead to part of the ceiling collapsing. Ideally they “should” be replaced – I know our neighbour replaced all of hers some years ago – however it’s also a bit of a shame to remove something so original. Let’s face it, that kind of plastering must have required a lot more work and skill than nowadays plastering techniques and I think it’s quite nice to keep the original building techniques! So we decided to repair the ceiling instead. (Plus, did I mention I hate dust?!)

We gave the existing ceiling a good inspection first to see how much movement there was. You can easily do this by just pressing on the plaster in several locations. Particularly around the cracks you might notice the plaster easily moves up and down. Depending on how much movement determines just how loose the plaster has become. If it’s loose, it’s quite likely to re-crack and perhaps even eventually fall down. We planned to patch these areas with plasterboard, however ours actually wasn’t that bad. There was some movement, but you had to really give a good push to notice, so we decided not to remove any plaster at all.

I’d read a few different ways to repair ceiling cracks in lath and plaster ceilings, so if you’re looking to repair yours, you might want to do a bit more research to see which way is best for you – but here’s how I did ours…

I used jointing filler to fill up the cracks. This stuff is basically a much thicker and stronger kind of poly-filler. It’s meant for filling cracks in between plasterboard (with scrim tape), which in my mind is pretty much the same as filling a crack in plaster right?! This stuff also dries super fast so you have to work with it quickly or else you’ll waste heaps of filler and need to keep mixing the stuff every 20 minutes or so.

A couple of hours later I was able to give it a good sand before going back over with the filler in any locations that needed a touch up to level the crack against the rest of the ceiling. You can already see it’s looking better!

Things to note: it does still get quite dusty. The poly-filler kind of dust. Still not quite as bad as plaster dust though!

Eurgh! I also recommend wearing a hat since the dust falls directly from above you, this will seriously save your hair from totally drying out and turning into a mega ruin! Of course make sure to wear a dust mask and goggles too!

And voila, the ceiling now looks totally crack-free! Actually I’m dead impressed. It’s a little lumpy in some locations where the crack was a bit more sunken, but for the most part I think once painted you would never know there had been a giant crack. Success!