Removing a section of solid wall for mixer valve & pipew

[chainsaw_masochist]

I need to install a shower/bath mixer valve within a solid wall. Ideally I would like to remove an entire vertical section of the wall from floor to ceiling about a foot wide and replace this with two panels of 18mm WBP plyboard thus creating a cavity for the valve and pipework.

This method, though, would prove time consuming and very messy so I am considering removing sufficient existing plaster and breezeblock material to create a suitably sized aperture to achieve the same result. The problem is how much of the wall would I safely be able to remove without risking weakening the wall with disastrous results? I would want to create a space of about 300mm x 400mm plus room for three pipes below and one pipe above. Just to be clear, this property is a flat in a 20’s or 30’s block so when I use the term ‘breezebock’ this may not be the same as the modern equivalent. It is though fairly easy to remove and appears to be composed of a brick formation.

Thanks in advance for any help.

 

[simonjay]

I need to install a shower/bath mixer valve within a solid wall. Ideally I would like to remove an entire vertical section of the wall from floor to ceiling about a foot wide and replace this with two panels of 18mm WBP plyboard thus creating a cavity for the valve and pipework.

This method, though, would prove time consuming and very messy so I am considering removing sufficient existing plaster and breezeblock material to create a suitably sized aperture to achieve the same result. The problem is how much of the wall would I safely be able to remove without risking weakening the wall with disastrous results? I would want to create a space of about 300mm x 400mm plus room for three pipes below and one pipe above. Just to be clear, this property is a flat in a 20’s or 30’s block so when I use the term ‘breezebock’ this may not be the same as the modern equivalent. It is though fairly easy to remove and appears to be composed of a brick formation.

Thanks in advance for any help.

Its called chasing out a wall, same for pipes or cables.
The only thing that matters is how much structural material you remove. So some of the depth can be gained from removing plaster.

Building regs specify maximum depth / width into bricks or blocks for horizontal or vertical runs. Maybe someone else can give the values off-hand.

But the amount you want to remove is rather over the top. Usually a bit of a "pit" in the wall for the valve, and 1 or 2 narrow channels for the pipes. If the pipes are copper they should be protected from any plaster which can cause corrosion, and hot pipes should be sleeved to allow for expansion.

Alternatively, you can batten the wall to give you a void behind, and cover it with some type of cement board or tile backer board. This also enables you to add some foam board insulation to the wall.

I'm sure you could take out 10mm depth over a very large area, but do you need to ?

Often a combination of techniques can gain you the space required.

Most builders would try to mount the bath / shower etc to that the gubbins is inside a stud wall instead. That way access is more possible if something goes wrong.

Simon.

 

[chainsaw_masochist]

The cavity must accommodate the mixer valve which is 75mm deep so it will require more than just the removal of plaster for a flush fit.

I have had a quick browse of the Building Regs Part A (Structure) but have not yet found where this would be covered. I will check it out in more detail later.

There is no option to mount the valve in a stud wall. My original idea of removing a whole section of wall from ceiling to floor would, effectively create a stud partition are that would seemingly make this task more straightforward but it is a good deal more work.

Thanks for your comments, though.