Routing Hot and Cold Pipes in Bathroom

[iMCaan]

Hi

 

We have UFH on both GF and FF. Both floors are block and beam. The FF will have 25mm insulation and then 50mm liquid screed.

On the FF, the gas engineer will run the pipes to the bathroom and then the plumber will use joints to re-route the pipes to the sink, bath and shower. Where do the pipes to sink, bath and shower need to be placed? 
1) within the insulation under the liquid screed 
2) etched into the concrete block wall behind plasterboard
3) up the wall and across the ceiling

 

Thanks

[Temp]

We also have B&B first floor but used 50mm insulation.

 

You can run water supply pipes in the insulation but best sleeve them with conduit. Maintain insulation on hot pipes. Can also run them up walls in slots cut in block work, we did this for wall mounted basin taps. If you have lots of space you can even build a false wall/service void with battens and Hardi backer board or similar.

 

Waste pipes need a fall on them which will mean they need to run in both insulation and screed. 50mm diameter pipe is recommended. If you want a wet room or low profile shower tray (eg walk in with no raised plinth) the waste pipe to the trap needs special planning and prep before screeding. It might even need to go through the floor and run to the stack in the ceiling of room below. Our's didn't... More info on request.

 

Edited November 17, 2023 by Temp

[iMCaan]

Thank you @Temp This is very useful information.

 

So since the hot and cold pipes have to be split for a feed to basin and shower, where are the pipe joints? In the insulation under the screed or notched into the wall? If in the insulation, what happens if the pipe joint leak starts leaking and need replacing?

 

I was thinking about walk-in wet room with linear drain but not going back to planning.

 

 

[iMCaan]

39 minutes ago, iMCaan said:

I was thinking about walk-in wet room with linear drain but not going back to planning.

Ignore this, it's Friday and had tough time at work. I can't seem to edit my posts even though I'm logged in. 

[Temp]

Our bathroom have some boxing along the wall below window sill for the concealed cistern. Either side we have an access hatch which houses isolation valves for basin/WC and shower. As that's where the split/joints are. Also has the "horizontal" 110mm run for WC to stack.

 

Edited November 17, 2023 by Temp

[Temp]

To fit our shower trays we removed a section of insulation under the tray. Then dry fitted the shower waste pipe and the lower part of the trap so it's in the right place. This was loosely supported in position at right height but in a way that allowed it to move vertically bit.

 

Then fitted a frame of pressure treated 2*4 or similar and 18mm WBP ply to support the tray at the right height. The WBP had a clearance hole in it that allows the trap to sit at roughly the height of the top of the WBP/underside of tray. It should be possible to pull the trap up about 0.5" further to allow for the thickness of mortar/adhesive used to fix the tray down. Test you can fit the tray and screw the top part of the trap through the hole into the bottom part.

 

Remove tray and plywood and glue up the pipes. Replace plywood and put rags in trap to stop debris getting in. Screed floor to top of plywood. Fix tray (with mortar/adhesive) and immediately screw in the top of the trap to be sure you can before adhesive sets. Check it level.

 

The heights need to be planned carefully to take into account of the screed and tile thickness plus fall to the drain.

 

It's a bit different for a linear drain but a similar amount of planning and prep is  needed before screeding.

 

 

 

 

 

[iMCaan]

I really appreciate the information you provided @Temp  it's not as straightforward as I initially thought. 

Like you said there's a lot to consider and plan.

 

Thank you