Recessing shelves into wall cavity

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scott12

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#281087 28-Jan-2021 19:22

I'm new to any kind of DIY that involves holes in the wall.
I've seen people online cut a hole in the gib and use the cavity space to make deeper shelves than they'd otherwise manage. This might add just enough depth that I can wall-amount AV equipment without it sticking out too far.

Is there any legal or practical reason I shouldn't do this?

Thanks.

mrdrifter

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#2643810 28-Jan-2021 19:41

Really depends on where the wall is located, if an external wall you will potentially ruin the thermal envelope of your house. If an internal wall, noise can cause an issue on the other side. Structurally as long as you don't cut through a supporting timber there shouldn't be an issue.

Edit: Spelling

jonherries

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#2643811 28-Jan-2021 19:58

mrdrifter:
Structurally as long as you don't cut through a supporting timber there shouldn't be an issue.

Edit: Spelling

Unless it is part of a bracing unit.

Jon

SomeoneSomewhere

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#2643837 28-Jan-2021 21:41

Never say never, but my experience with braceline has been that they're happy to have fairly large (switchboard-sized) hoes in the middle of a bracing element, as long as it's 150mm+ (I think the figure may actually have been 75mm) from any edges or corners - check the gib site guide, and remember that it will be a rectangle; i.e. the bracing element may not extend the width of the wall if there's something like a ceiling height change.

I would expect plywood to have similar tolerances.

Expect there to be electrical/data cables in the wall, and pipes too.

nickb800

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#2643897 29-Jan-2021 06:20

SomeoneSomewhere:
Never say never, but my experience with braceline has been that they're happy to have fairly large (switchboard-sized) hoes in the middle of a bracing element, as long as it's 150mm+ (I think the figure may actually have been 75mm) from any edges or corners - check the gib site guide, and remember that it will be a rectangle; i.e. the bracing element may not extend the width of the wall if there's something like a ceiling height change.

I would expect plywood to have similar tolerances.

Expect there to be electrical/data cables in the wall, and pipes too.

Not allowed according to GIB - they specify that cutouts within a bracing element should be 90x90mm max, and at least 90mm from the perimeter. Larger cutouts needed to be outside of the bracing element.

Note that bracing elements don't necessarily involve the whole sheet or wall, so for example if a switchboard cutout was designed in from the start, then the wall either side of the switchboard would be designated as separate bracing elements, even if they are part of the same physical sheet.

The OP needs to find the building plans and/or someone experienced to assess the plans/building to correctly identify if the wall lining is a bracing element or not. Generally speaking, if the building is original pre 1970s then the wall lining is unlikely to be needed for bracing (as they used diagonal timber framing instead)

SomeoneSomewhere

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#2643898 29-Jan-2021 06:23

I think you're right. In hindsight, it might have been light switches etc that couldn't be near the edge; we had to relocate switchboards.

D1023319

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#2644401 30-Jan-2021 12:59

nickb800: The OP needs to find the building plans and/or someone experienced to assess the plans/building to correctly identify if the wall lining is a bracing element or not. Generally speaking, if the building is original pre 1970s then the wall lining is unlikely to be needed for bracing (as they used diagonal timber framing instead)

Interesting the difference between new and old houses.
Out of interest in my 1920's house i recessed a hand basin behind the toilet door

As the Stud gap was insufficient - I removed the whole wall lining and created a frame

There are only diagonals in the outer walls of our house.

It was too expensive to buy a custom splashback so I bought a larger one from Bunnings and glued it to the gib wall lining of the opposite room.

scott12

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#2644416 30-Jan-2021 14:12

Thanks for all the well-informed responses.
The wall is part of the thermal envelope (thanks mrdrifter) and the bracing thing (thanks jon and others) is another question I didn't know needed asking, so I might have to declare the whole thing above my pay grade.
Plus it appears my studs are 40cm or so spacing so it wouldn't be a very wide shelf!

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andrewNZ

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#2644430 30-Jan-2021 15:47

Also check for possible electrical cables in the wall. Check both sides of the wall for electrical fittings.

D1023319

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#2644638 31-Jan-2021 09:22

scott12:

Plus it appears my studs are 40cm or so spacing so it wouldn't be a very wide shelf!

As per my middle photo above - you can cut studs and insert a horizontal framing timber with suitable supports down to the baseplate on the side to increase the width of the recess
Its also a method to move the location of the shelf to avoid electrical sockets on the opposing wall.

Bung

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#2644639 31-Jan-2021 09:31

Studs at 400mm centres suggests the wall isn't a simple single storey. Only plumbers cut into framing with no regard.

scott12

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#2644781 31-Jan-2021 15:53

Just to provide context, it's a late 1970s brick and tile unit in a block of two (pelmets and all). You'll have seen a dozen like it if you were ever looking at the low end of the market in Auckland.