Greetings, new to the forum here. I’m renovating my master bath and am about to rough in the shower. I’ve totally gutted the previous tile (which leaked) which was just on green board with no insulation behind. This is concrete block construction, so the previous green board was nailed to 1×2 sleepers attached to the block (with no insulation).
due to leaking, the green board and even much of the wood structure was pretty deteriorated. i’ve gutted back to pure concrete block. I’m going to install 2x sleepers to give me a bit more depth and insulate with foam board.
now to the problem. to rough in the new temp valve and multiple water volume controls (for multiple shower heads plus body sprays) it looks like the plumbing needs to end up about a 1/2 inch ‘inset’ into the concrete block for controls to end up at correct placement for the new tile surface. I can’t increase the sleeper thickness due to other constraints. I’m thinking i’m going to have to take a diamond blade and cut 1/2 inch channels in the block for the pipes and fittings and valves to all ride in.
any other thoughts / caveats?
thanks in advance, David S. Tampa, Fl
Replies
as long as the copper does not touch the concrete product it be fine. If it has too, uou have to sleeve the copper. cement will eat copper. cement would refer to any concrete product, cmu, concrete , mortar etc.
thanks brownbagg...
is there any standard material to sleeve the copper with? or does that mean, just use anything that works.
for example, could put a layer of felt paper between the copper and the concrete (i've seen that before).
is that viable?
David S. - Tampa, Fl
If you end up cutting into the block wall and it is hollow I would spray foam behind the mixing valve or it is likely to freeze.
foam insulationgoes right around the pipeshould be able to find it at lowes or home depotit will cut down on the pipes sweating behind the wall tooNo Tag
they make a pvc sleeve, it a soft material that the pipe slips into. it comes in red or blue.
Portland cement does not eat up copper. Copper is commonly embedded in mortar for chimney flashing and counterflashing on walls. It is highly recommended for flashing in brick veneer systems. Copper lines embedded in concrete have held up for decades in radiant heating systems. (I'm aware that they eventually fail and that plastic is better. However, the failure is not due to corrosion.)
Wet portland cement products do corrode aluminum.
Check this out:
http://www.copper.org/applications/plumbing/techcorner/problem_embedding_copper_concrete.html
Thanks for the link. Now I feel better about the copper loops we used to make a radiant floor 30 yrs ago.
Thanks to all for your comments. I was quiet over the weekend because i was a soldering (sweating) fool!
after reading some of your comments and concerns, I took a step back to think "outside the box". Instead of cutting channels into the block for the pipes, I decided to add another 3/4 inch to the sleepers. This means that the wall is not going to line up (somewhere after the tile ends) with some other part of walls, but I think we can find a way to build a nice looking transition and make that ok.
but on the "good side", it now means I have 1/4 inch or so gap between all the pipes and the block, I didn't have to cut channels in the block which would have been a mess plus possibly weakened the wall as some pointed out, plus i have more room for insulation.
so I was able to rough in the main temp valve, 2 volume control valves and 3 body-sprays. still have one last volume control valve to rough in and the shower riser.
thanks for all your comments, David S. - Tampa, FL
Hopefully your valve, with no rear access, has screwdriver stops.
Jeff
Yeah, isolate the copper from any contact with the concrete. Keep in mind that the pipe will move slightly with water "hammer" and with thermal expansion/contraction, so something that could abrade through (like a couple of layers of builder's felt) is probably not the best choice. As mentioned, the foam rubber pipe insulation is probably a reasonable choice, or you could glue some sheet foam insulation in place behind the pipe using construction adhesive. Or just create enough of a space around the pipe that you're confident contact will never occur.
Of course, if you live somewhere where it gets cold, and this is in an outside wall, you probably need to rethink things to keep the pipes from freezing.
Oh, I see -- Tampa ... probably no need to worry about things freezing.
I guess the only other question(s) I have is: how structural is the wall, and how long a channel are you cutting in it?
k