How to Fill a Large Crack in a Wall in new Build Property

Postby earlydoors153 » Sun Jan 21, 2018 12:47 pm

Hi - I moved into a new build a couple of years back

Since then these large cracks have been appearing. I want to fill them in and have tried to use the Polyfilla Deep Gap - however the crack is so large that I can't seem to get a layer thick enough to sit in the crack. When it dries, it just sinks through and falls into the storage space underneath.

Any ideas how i can fill this up? Should I use a different product? Or a different technique?

Appreciate your help
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Gorilla Glue heavy duty grab adhesive

Postby Dunny79 » Mon Jan 22, 2018 12:40 pm

Hi. Cracks appearing in walls on new builds are quite common although this gap is rather large. The problem you’ve got is there’s nothing at the back of the gap to fill to so as you’ve found out it’ll fall out. So what you need to do is create something to fill to so you’ve got 3 surfaces the filler can adhere to. There’s a few things you can do. If you can get inside the storage space, you could screw some plasterboard or wood over the gap or you could try caulking the gap to create something to fill to. If you get a caulk/silicone gun and a tube of caulk (not silicone). Cut the nossel quite large and at angle. Clean the gap byeither blowing out the dust or vac it, with the flat part of the nossel aimed at the wood on bottom (it looks like wood), Apply a good amount of caulk along the gap. Don’t try and put too much in the gap in one go as you’ll experience the same problem with it falling out. It’s best to put a bit in, leave it to go off a few hours then repeat. Make sure the caulk doesn’t protrude from the gap as caulk can’t be sanded. Once you fill most of the hole, leave for at 24 hours, longer if you can to fully harden, then fill. Hope this makes sense
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