Do largish holes in plasterboard need support?

Jono8 · 26 May 2021 at 13:02

Cut a whole in my lounge wall to give me a few more cm needed for an inset fireplace to sit nicely against the backplate.

I've cut the hole and there are no studs affected or cut etc. Its just a section of plasterboard removed.

However part of me is worried it might need some support or something? Should I build a wooden frame within it to add that support or will it be fine?

I'm just concerned that removing a fairly large ish (about 55cm x 65cm) might affect the plasterboard above.

Or am I worrying over nothing?

Picture here (I am going to fill the gaps round the egdes)

bremen1874 · 26 May 2021 at 13:06

As long as it's still firmly attached to the wall I wouldn't be worrying about it.

thenewoc · 26 May 2021 at 13:14

If there's some flex in what's left around the edges you could squash some ready mixed filler into the gap which would act in a similar way to the dot n dab adhesive that seems to be showing in a couple of places.

Jono8 · 26 May 2021 at 13:20

thenewoc said:
If there's some flex in what's left around the edges you could squash some ready mixed filler into the gap which would act in a similar way to the dot n dab adhesive that seems to be showing in a couple of places.

Yeh that is what I was intending to do in the open gaps anyway (just stuff it with filler)

You reckon that would be enough?

Was wondering whether to put a sort of wooden lintel type thing across the top, attached to the breeze block to support the above plasterboard , but that might be unnecessary.

thenewoc · 26 May 2021 at 13:24

I would just stuff it in a few places, not necessary to do it all the way around. No need for wood as the rest of the plasterboard will be supported by dot n dab.

If you were fitting anything heavy above that area like a TV then it would be mounted into the block work anyway with suitable fixings.

Once you've fitted the mock fireplace into the recess I'd go around the edges with a filler spatula and some ready mixed plaster skim. Try and leave a couple of mm gap though and finish off with a neat bead of Flexible Gap Polyfilla using a fugi tool.

https://www.amazon.co.uk/Polycell-F...ble+gap+polyfilla&qid=1622032318&s=diy&sr=1-2

Jono8 · 26 May 2021 at 13:30

thenewoc said:
I would just stuff it in a few places, not necessary to do it all the way around. No need for wood as the rest of the plasterboard will be supported by dot n dab.

If you were fitting anything heavy above that area like a TV then it would be mounted into the block work anyway with suitable fixings.

Well there is a relatively heavy large mirror above it which is in the plasterboard using heavy duty fixings (its been there 2 and a half years

) .

I just wonder if some sort of support might make me feel better, even if it is completely unnecessary

I just know nothing really about how that sort of hole would affect the integrity of the rest of the plasterboard wall and whether it would lead to any of the bits above sagging or something.

thenewoc · 26 May 2021 at 13:37

You should really use some heavy duty fixings that go into the block work rather than just rely on sheer strength of the plasterboard. Long screws and long wall fixings. You can get plastic wall rawlplug type fixings that you can cut to length so you can drill into the block work at a reasonable depth to accommodate nice long screws.

The plasterboard itself shouldn't go anywhere with it being dot and dabbed with adhesive since it will be in random places all over.

Jono8 · 26 May 2021 at 13:42

thenewoc said:
You should really use some heavy duty fixings that go into the block work rather than just rely on sheer strength of the plasterboard. Long screws and long wall fixings. You can get plastic wall rawlplug type fixings that you can cut to length so you can drill into the block work at a reasonable depth to accommodate nice long screws.

I dont think it's that heavy to warrant it. I've found the wall anchors that you crimp so they grip behind to be remarkably good. Have put stuff up in various homes for the last 7 or 8 years of home ownership with them and not had something fall off yet

200sols · 26 May 2021 at 13:50

Decent fixings you can hang surprising heavy items on just plasterboard, I am talking 10s of kilos and that is before you get to some like gripit which are tested over 100kilos!

Jono8 · 26 May 2021 at 13:50

thenewoc said:
The plasterboard itself shouldn't go anywhere with it being dot and dabbed with adhesive since it will be in random places all over.

I think your right. Looking at it at the bottom, the plasterboard isn't even really touching the floor. It's just hung on the wall anyway so supporting it from the ground is probably pointless.

thenewoc · 26 May 2021 at 13:58

Jono8 said:
I dont think it's that heavy to warrant it. I've found the wall anchors that you crimp so they grip behind to be remarkably good. Have put stuff up in various homes for the last 7 or 8 years of home ownership with them and not had something fall off yet

The metal wall anchors are superb but they're really meant for a stud wall as they need room at the back to open up.

theone8181 · 26 May 2021 at 19:36

thenewoc said:
The metal wall anchors are superb but they're really meant for a stud wall as they need room at the back to open up.

Some of the dot and dab walls in our house seems to have a big enough gap for them to work :eek:

.

NathG79 · 26 May 2021 at 19:50

Fix 4 vertical lengths of doorstop to the softblock with rawlplugs and screws, then screw the new plasterboard to that.
providing the gap behind is wide enough to acomadate the plasterboard fitting flush.

edit. Sorry, thought you wanted to board up the hole.

just mix up some dot and dab adheisve and tuck it in against the opening.

Quartz · 26 May 2021 at 19:59

Jono8 said:
Should I build a wooden frame within it to add that support or will it be fine?

A wood frame would make it look nice and prevent accidental damage.

Semple · 26 May 2021 at 22:50

200sols said:
Decent fixings you can hang surprising heavy items on just plasterboard, I am talking 10s of kilos and that is before you get to some like gripit which are tested over 100kilos!

I used gripits for mounting the TV to a plasterboard wall, went for the highest rated which I think is like 120-140Kg even though the TV weighs a fraction of that - figured I'd just go overboard to be safe.

bigfoot4616 · 26 May 2021 at 23:58

if there is any movement round the edges get a tin of this and fill the edges with it
https://www.sealantsandtoolsdirect....iL0Ix8Epv4Nf8YilcRk2gSLsmFnkxZ7hoCnooQAvD_BwE

i have seen full rooms dot and dabbed with it but i still prefer to use driwall adhesive.

Jono8 · 27 May 2021 at 15:40

Thanks all. I've done a bit.of both. Squeezed some filler into the gaps etc and put a small wooden frame around it as well for peace of mind (just in case the plasterboard hasn't any sort of support). Sealed it all in so there is no break in the cavity as such.

Probably totally useless, but better safe than sorry I guess.

200sols · 27 May 2021 at 15:59

Jono8 said:
Thanks all. I've done a bit.of both. Squeezed some filler into the gaps etc and put a small wooden frame around it as well for peace of mind (just in case the plasterboard hasn't any sort of support). Sealed it all in so there is no break in the cavity as such.

Probably totally useless, but better safe than sorry I guess.

Sounds good. You have to remember when they build these houses they do the absolute bare minimum so a little over engineering when doing some DIY is never a bad idea