Best method to repair this large hole?

Uhtred · 9 May 2022 at 12:53

Under the stairs there's the cupboard where the boiler used to be and when it was moved it left some rather ugly holes in the wall. I can't really tell what it's made of but I'm guessing it's cinder block or something like that.

What's my best bet to patch this up? I can only get to it from one side, there's a void on the other where pipes run.

Cement or thistle undercoat perhaps?

https://uhtredthebold22.tumblr.com%2Fpost%2F683773150380621824

Uhtred · 9 May 2022 at 14:30

I've had a good look, it's cinder block with plasterboard dot dab and plaster on top.

I'm now thinking to get a spare block or two, cement it in behind and then thistle undercoat with some polly filler to finish. I've not worked with cement before but how hard can it be

Uhtred · 9 May 2022 at 15:22

i've used expanding foam to stop movement of plasterboard but I hadn't considered using it here. That's a good shout, i'll give it a go, thanks!

I'll clean it out as best I can and put some pva in to help with the dust, foam it, cut it back and filler on top

Uhtred · 9 May 2022 at 17:24

mattyfez said:
Or just do it properly like in the video above?

But really, if it's inside a cupboard i'd probably just tidy the hole up and leave it as-is.

That's talking about 'drywall' which in this case is talking about timber frame using tape and join which is really common in the US, Canada and others (and increasingly so here I believe) but I'm working with 'dot and dab' which means the methods mentioned there will raise the surface slightly. Would it be noticeable? Meh probably not but even so I would prefer to use something that keeps it flush with the plaster.

By the way the best tip in that video is using a timber backing with a small piece of plasterboard. I've seen it done where you remove the paper layer from the back which allows you to cover it with filler keeping it flush and blending it in really easily which is great for fixing holes in the ceiling made from downlight installations for instance but, in any case, for a dot dab wall I haven't got the clearance to put timber behind the boards.

Thanks for the input everyone, I've got foam to hand so that's what i'm going to try this weekend.