Plumbing questions - qualpex in concrete?

FrankGrimes

Building an extension onto the side of our house and am doing most of the work myself. Ready to pour the concrete slab soon enough. The wall will eventually be knocked where our dining room currently is to create kitchen diner single room in the extension. Plumber left copper pipe feeds for the extension ready in the dining room floor ready to be extended into the extension. Plumber did the internal replumb on existing house but was a cowboy so not having him back for the extension.

I need to run the pipes in for the extension (they will be run in the ground) before I pour the concrete slab over them. I will just be running the pipes and getting a plumber later to connect it up to the pipes in dining room when the wall is broken through. Considering the pipes will end up embedded in concrete with a solid wood floor over it, can I get away with using Qualpex pipes or do I really need to continue it in copper?

Also, my mate was digging the foundations in a mini digger and hit off the gas pipe feeding from the gas box into the ceiling of the sitting room. This pipe is running up the side wall of the (end of terrace) house (gas box is on the front wall) and then in through the sitting room joists. The external wall it is currently running up will be an internal wall on the extension so it will be slabbed over. The pipe is badly dented but we checked immediately and theres no leaks. I think this piece needs to be replaced though I’m interested in opinions as to whether the whole gas pipe should be moved and where to (I can only think front wall which would destroy appearance).

Thanks.

beldin

Quoting the web site on the qualplex question
www.qpl.ie

Q: Can Qual-PEX be buried in concrete?
A: Yes. Concrete does not have an adverse effect on Qual-PEX and the pipe can be buried directly in concrete (subject to bye-laws).

FrankGrimes

thanks beldin. However, my concern is more to do with is it advisable to bury qualpex joints (assuming compression fittings are most reliable) in concrete, or should only copper welded joints be used in this case?

stapeler

I'd go with the brass compression fittings to joint the two. I'd even be tempted to use the pust fittings which I have a lot of faith in.

karltimber

Hi Frank

outside of the one connection you need to make - try not use any other in-concrete connections.
I got a 100m of 1/2" qual pex for euro90.
You can also get 50m rolls - so no joints can be under concrete at all.

I will be doing the same as you and will use compression fittings on 1/2 and 3/4" qual pex. remember to use some hemp and boss white for the connection threads.

question - is there a different boss white ie boss green for drinking water connections ???

karl.

Zena

Only use push fit and make sure that you tape up the fittings well so that they do not come into contact with the concrete,

If you are siting a boiler away from the house use 1" pipe only.

Zena

Use only copper pipe and solder the joints, Plastic pipe cannot be used and is not allowed for Gas

FrankGrimes

Thanks folks.

Zena - I'd have thought a compression fitting would be more reliable than a push fitting (e.g. Tectite) - is this not the case?

The gas pipe will only be joined above ground and I'll make sure copper is used at all times for the gas pipe.

Karltimber - theres two rads going in the extension so I will need to branch off at some point so it looks like I'll need two joints on each pipe - one in dining room and one in extension. Both would be embedded in the concrete - does this sound ok?

karltimber

FrankGrimes wrote:

Karltimber - theres two rads going in the extension so I will need to branch off at some point so it looks like I'll need two joints on each pipe - one in dining room and one in extension. Both would be embedded in the concrete - does this sound ok?

A builder who I was going to use was going to do the following.
when pouring the floor, he was going to put down 3" timber at the edge of the room. pour the floor and lift the timber before set. run all your pipes in this cavity to where the rads are and fill in with a light mix -to cover all pipes.
thought it was a good idea -not using this guy now for other reasons but will keep that in mind.

I think I am doing the exact same ext as you over the next few weeks and outside the above idea - I will prob just use compression fittings with hemp and boss white --will seal them very well. insulate and put tape over joins to protect from concrete. remember to put some steel rod into the ground to hold the copper in position when pouring the concrete.

what size pipes are you using from the boiler -3/4 or inch. and then 1/2" T's to rads ??

hope this helps

FrankGrimes

Hey Karl,

Its boss green for drinking water pipes and boss white for others.

The copper pipes in the dining room floor (in a pre-cut trench in the concrete there - that room still a work in progress) are 3/4 inch copper.

I am thinking of running 3/4 inch qualpex barrier pipe (was advised to get this - is it necessary?) to the nearest rad in the extension and then branch off from their using a 3/4 inch to 1/2inch compression fitting and run 1/2 inch qualpex to the second rad. Is this the best idea or should I just use 3/4 inch all the way to the rads and convert it to 1/2 just before breaking out for the rad valves?

CJhaughey

You can get qualpex inside a corrugated black plastic sleeve , I would use this if you are burying it in concrete.
If the concrete cracks it won't affect the qpex directly.