Burying PB pipes in wall

Smokeless03 · Feb 4, 2015

Hello, I have gone mad and stripped all the old tiles and lime plaster off the wall of our toilet - it was possibly fashionable in 1914 but not now. Anyway, the pipe work used to run down the walls in full view and so now I want to hide them in the cement/ plaster and have been advised to use polypipe and speed fit joints but know this is ok with copper if well sheathed but not heard of using PB pipe. Can I bury the pipe and speed fit wall end plate in the wall and then plaster over it? Thought I'd leave short length of 15mm copper pipe to show through the plaster to connect to the new shiny sink and toilet, does that sound like a reasonable or sensible option?

lame plumber · Feb 4, 2015

i wouldnt bury any fitting other than soldered in a wall

Toxic Ted · Feb 4, 2015

Nor me i'm affraid!

CXR100 · Feb 4, 2015

nor me, the least joints the better, use copper. also plan out where your fixing holes for mirrors , shelves etc will go , no good burying them there!!! I wrap them in pipe felt as this acts like a bit of insulation aswell , then secure with a few strands of pvc tape, don't just cover them in pvc tape as they will 100% be scratched back to copper in places by the time plasterers finish!!! and take time to smooth out chase so pipes will not rub against a sharp piece of brick .

Worcester · Feb 5, 2015

Nope don't bury it though, reason? (amongst others) Expansion:

A 3m length of copper pipe will extend by about 3mm when temp raised from 10 to 60, (cold to hot) plastic pipe will increase its length by 30mm over the same length! so it'll crack your plaster if buried like that.

plumben · Feb 5, 2015

id use copper and soldered joints, you shouldn't put a mechanical joint where it cant be seen IMO and that's what id class speed fit as

craigy · Feb 5, 2015

Valid points above. Plastic is ok to bury as long as there is no joints hidden, it's located in a corner away from DIY enthusiasts and when the plastering is being done, the pipes to be covered are at full operating temperature and thus at maximum expansion size, so when the plaster dries to suit the expanded size of pipe, the plaster will never crack. Sounds like you are installing drops to supply outlets for aesthetics. Use continued copper in that case behind plaster and either buy copper tube that is pre wrapped and pricey or buy proper tape and wrap it. If your using plastic supply then you can join your copper behind the wall to the plastic above. Why not dry line if you have to use plastic? The gauge between masonary and PB is sufficient to guarantee no mortar in contact with fittings(still risky) or better still, you can bend the pipe to protrude horizontally if sufficient gap.

AWheating · Feb 5, 2015

Plastic with no joints is ok for dabbed walls. Copper pvc coated and coverd with stitch lagging would be my choice for most situations.

Smokeless03 · Feb 5, 2015

Thank you all - really useful advice. I just felt it would be risky burying a push fit so thanks to you all will be going with copper as you all suggest. Much appreciated.