Installing Underfloor pipes, any tips (PICTURES !)

[brumylad]

This ground floor flat has concrete floor and ceilings. Open vented system, can't convert to sealed due to boiler instructions. Only realistic route for pipework is under 35mm floor screed. Chiselled out chase in screed with club hammer + electricians chisel.

I would have prefered to cover 15mm runs with 18mm ply but not enough screed depth.

Therefore have used PVC coated copper. This 15mm tube is coated with about 1mm thick pvc, is dark green, comes in a coil, is a pain in the ass cos it needs straightening before use, mercifully accepts normal fittings, costs a rudy fortune (£12 + vat for 3m).

I removed the skirting and some wall brick to hide the pipes in the hall way at least.

I will cover over with 1:3 mastercrete:sharp sand.

Any comments as to how it could have been done easier, better or quicker.

Screed removed concrete slab exposed!

And the other side of that wall !

 

[JPC]

i take it its for a rad in another room.
could it not have done from a drop (pipework in the ceiling and down the wall nr where the new rad is going ?

 

[brumylad]

no cos open vented and F&E can not be raised high enough to reliably fill pipes at such a high level

 

[Paul Barker]

If the pipe above skirting (what ius that crap 3inch or something? in Scarborough 7 inch is small except in council houses where they used 3 inch half round quadrant, and what a pigs ear they made of that, and new builds which I stay well clear of on the basis they haven't built houses to an acceptable standard since 1880).

Anyhow if that pipe feeds one rad and skirting had actually been skirting I would maybe have used 8mm copper chased wall and glued skirting over it.

In your situation I might have put some mt4 trunking along the skirting and run the pipes in that nail clipping them through the trunking.

The solid floor couldn't be done much different. I'd probably have just wraped ordinary copper with insulating tape or closure plate tape, and if at all possible to fit them in run them inside 3/4 overflow, or at least wraped them in laminated floor underlay.

 

[brumylad]

thanks for the suggestions paul, I like the idea of running the micro bore behind the skirting, I'll keep that in mind for future jobs..

I had thought of microbore but I was worried that because this was the rad on the longest pipe run, and all the other rads were piped in 15mm, I might have problems balancing everything.

The clips I have used on the 15mm will actually accept clip on conduit but I can't say I like the stuff. I think there's a market for quality plumbing conduit, the electricians seem to have a good selection these days.

Yes this is an X council flat, thrown together on the cheap. I agree with your point about new builds, some of them have vapour barrier membranes in the walls, retro fitting them with any new services will be a nightmare if you're conscientious and want to do a good job.

 

[chrishutt]

For the underfloor run you could have used 10mm plastic threaded through 15mm plastic acting as a conduit. The 15mm would be set in the screed but the 10mm could always be pulled out and replaced if there was a problem.

You're right that balancing is a bit tricky with one long branch of 10mm in a 15mm system, but if most rads have TRVs the system will tend to be self-adjusting.

 

[Paul Barker]

MT4 trunking is very neat with two 15mm pipes in it, and cheaper than the plumbing stuff. You have to use nail clips though, Talon clips won't fit inside.

 

[brumylad]

thanks again Paul and Chris.

Paul, what about soldering with the MT4 trucking, how do you get round burning the plastic?

 

[Paul Barker]

I haven't had to solder inside it, but if I did I'd make up ashield with tin folded to shape, wet cloth between plastic and tin, run flame along fitting instead of perpendicular. My blow torch has a suitable medium sized flame that doesn't spread too far, yet is hot enough for 28mm pipe. I've noticed the standard flame with the rotten burger is much too much of a flame thrower, Ian my trainee has one. I bought him a pensil flame head, but that's too much of a spot flame for my liking, very hot in a small part, but not enough even coverage though better than the standard flame thrower. I like to have my burner.

 

[brumylad]

thanks again for your advice Paul.