Screeding a new shower, part 1 - grid drain

Photos:
https://drive.google.com/drive/folders/0BxGOCqCJ0x5Fb05oemlzZjJrSzg?usp=sharing
This is going to be a wet room, shower one side, loo and basin the other, underfloor heating to keep it dry.
Stage 1 was to set the ACO drain in place.
on top of the concrete will be 50mm celotex, UFH pipe and 75mm of fibre reinforced screed.
We used some beefy brackets from Screwfix, then some M10 bolts plus locking nuts to set the ACO drain some 12mm below the screed height of the adjoining lobby floor.
We will lay the screed level in the entrance (so it marries to the doorway correctly), then slopes 12mm over 600mm to this drain. Floor in shower will slope back towards same drain.
Drain was fiddly - but got it right after many dry fits followed but solvent welding. As recommended, we wrapped the bottle trap in foam and put some thin foam (pipe insulation split open) around the pipes, so they will be able to move and expand slightly rather than be solidly buried in concrete and screed.
Ideally the pipe would go down under the ACO strip, but the builders installed off to one side as it was convenient to intercept the 110 pipe below that takes the grey water from the kitchen and bathroom.
However, there'll be plenty of screed over this, so it will be solid enough.
Tested the drain and flow is excellent :)
To be continued....
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Interesting. I have this job shortly. My insulation will be 100mm and the floor is block and beam but I suppose holes can still be made.
Is the fancy rail temporary or part of the final install?

--
Tim Lamb

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 06/05/17 22:31, Tim Lamb wrote:

Just to add - this really held the drain solid - I am hoping it will not move a bit whilst packing screed around it.

My aim was for 75mm insulation, but the concrete came up a little high and I did not want to compromise the screed thickness in case it cracked.

The wood battens?
I have some angle ali strip to screw to those, set at the top of a 3x2" tamping bar. The bar will have "ears" of 2x1" screwed on top and will run over the ali rails to give the correct finish height - one level section and 2 sloping sections.
I've done this before with wood bars screwed to the wall, but sometimes the drill wanders when screwing to a brick wall, so prefixing battens allows the ali guides to be screwed with more precision. That's the theory! Will find out in 2 weeks if it works...
We're using a 3:1 dryish mix for the screed - I've calculated 5 bags of cement to 15 bags sand (did the density calcs, 25kg dryish sand is very similar volume to 25kg cement). Ordered 8 bags cement and 24 sand just in case (and spare bagged is easy to put away for little jobs). But it is a small area...
I've got to work out a pipe layout for the UFH now. It's not an easy area to lay pipe allowing for the bend radii. I did the conservatory with a massive double spiral, but that was a nice open area. This'll need a bit of drawing out first, especially as I have to thread under that drain as it's set up nicely and I don't want to move it now.
How big's your floor?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tim Watts wrote:

    Why would anyone install piped under floor heating? Radiators work much better IME and are relatively easily adjustable. Also cheaper.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 07/05/17 09:02, Capitol wrote:

Because radiators don't work better and are in fact more expensive if installed at build time. And UFH is just as easy to 'adjust' with controls on each zone.
They are also very ugly and dirt traps.
--
"Women actually are capable of being far more than the feminists will
let them."
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 07/05/17 09:02, Capitol wrote:

With all due respect, that is a very silly generalisation.
1) It's a wetroom and warm floor dries quicker with UFH;
2) There's not much space and a radiator would rust in such an environment;
3) 300W of UFH in a tiny area is hardly going to break the bank and a bathroom in out household needs ot be warm most of the time as people take showers at all sorts of times;
4) It was one of two areas of new floor I have, so the opportunity existed to put in insulation. The rest of the house will have radiators. Except the conservatory, which has UFH and an air blower (wet). The idea there is to run the UFH in autumn and spring when it only needs a bit to make it nice. Then run the UFH very low in winter just to keep the floor from becoming like ice, and use the air blower for on demand heating.
I've stayed in a number of holiday locations with UFH and wilst I agree with you that it is not very controllable, especially in bedrooms which I like warm in the morning and cold at night, it's brilliant in bathrooms.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sunday, 7 May 2017 09:28:00 UTC+1, Tim Watts wrote:

not very controllable isn't a problem if it's only used to supply the portion of the heat one can pretty much rely on needing.
NT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I've done it in a couple of upstairs bathrooms by snaking 10mm microbore up and down between the floor joists. Since it's not in direct contact with the floor, it runs at full radiator temperature and doesn't require any mixing valves. In the first bathroom, I brought the end up to a TRV in the room. In the second bathroom, I brought the end up to feed the towel rail, which includes a TRV too.
Both used two parallel runs of 10mm microbore just in case the flow resistance of a single run was too high. Also sprayed the top of the copper with a thin coat of black paint, to improve the emissivity (any colour will work, but bare copper has a low emissivity, which reduces radiated heat given off).
These have worked very well, and were very cheap to do - pretty much just the cost of a coil of microbore.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Er.. no. The rails. I think elsewhere you say this is for screed levelling purposes. All the floor screeds here were laid manually by a bloke on hands and knees:-)

Will you add fibre reinforcement?

My underfloor heating suppliers provided a CD layout of pipe runs and routes.

The wet room is tiny. 1.5mx2.0m. Utility 2.4mx3.3m and study 3.2mx3.3m.
I plant to find contractors to do the job and will go for a dry mix with fibre reinforcing.
--
Tim Lamb

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 07/05/17 11:26, Tim Lamb wrote:

Rails? Which picture are you looking at? If you mean the shiny stainless thing, that's the ACO drain strip and that gets buried level with the screed.

Absolutely.
I'm using:
https://www.travisperkins.co.uk/TDP-20mm-Fibres-For-Screed-and-Concrete-900g/p/495654
As far as I can tell, the dosing rate is 90g/25kg bag of cement - I'll add a little extra.
I was considering light stainless mesh instead - but a) it's hard to get and expensive; b) with UFH tubes, that drain, lack of space, it will be a bastard to get in.
We're going to lay the pipes last - then after pressurising them with a little adaptor and a bike pump (filled with water to reduce the bang if anything flies off), we'll dump the first barrow of screed on the pipes by the door. Then the second barrow. But will will only loosely flatten and use this as a platform to deal with the section at the back. Once that's done, we'll work backwards out the door, fixing up the bit we dumped first.
I watched a builder doing our conservatory (also UFH pipe that I laid for him). I asked "how will you not mash the pipes"? And this is what he did - chucked the screed through the door and used that to wheel the barrow on with the 2nd load, etc. When he had 90% of it down, he then tamped and levelled off. Seemed to work well.

Handy!

Wet room is identical to mine :)

Our builder got readymix screed with the conservatory screed. But the delivery was unreliable - many days delay as the mixer company kept finding better jobs to supply.
We'll mix our own as it's only 1/2 ton - about 5 mixes. I've just overhauled my 3rd hand massive Clarke mixer and added a waterproof switch and new cable all ready. Gawd knows how it still works - it's been sitting uncovered for years round the back of the shed!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Oh! It looked a bit grand for building levels:-) I haven't really got to grips with this yet. Ceramic tile floor. Difficult to lay a fall to a central drain...

Architect suggested chicken wire but I think fibre easier.

Yes. Where did you acquire the adaptor for pressurising the pipe? ISTR TNP hiring a system for his house. I have two separate runs to do. The wet room is coupled to the utility area.
--
Tim Lamb

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 07/05/17 12:47, Tim Lamb wrote:

Expensive too! They know how to bone you for "bathroom drains". Also one of the first things I bought and the last to be deployed!!

Shouldn't be any different to my plan. I've kept the floor level until 2 whole 300mm tiles from the drain Then it switches immediately to a slope towards the drain. The change of level will happen on a whole tile joint. The shower bit is dead plat but tilted back towards the drain.
A square centre drain is harder - you really have to have a 4 way funnel into it and diagonal tile joints radiating outwards.
I could possibly get away without a slope on the loo side of my drain, but I wanted a catchment zone for overspray to be able to drain back.

It does work - surprising considering...
One thing my conservatory builder did wrong:
He set in 3 scaffold poles into the screed to act as level guides. Then removed then and patched in some spare screed. The patches did not bond well and a series of cracks appeared along all 3 pole positions.
I had to cross cut slots and resin in some concrete stitch repair stainless studs (200mm long). No problems after tiling, but without I could see it cracking through the tiles.
I think if you had to bond screed to packed screed with a polished edge like this, rake the unset polished edge with a screwdriver first to stir up some fibers then add screed so it intermingles.

It's a really simple one: (not the fancy one with a built in pump):
http://www.screwfix.com/p/monument-dry-pressure-test-kit/72940
You do have to go to 10 bar which is a hell of a pressure, then back off to something lower whilst screeding. This seems to be because the pipe stretches - if you go to say 7 bar from zero, you will see (at least with JG Layflat pipe) that the pressure gradually drops. This is not necessarily a leak, but the pipe relaxing.
Car footpumps struggle with 10 bar, a bike pump seems to work better.
Worth filling with water first as otherwise it takes ages and you store an unholy amount of explosive energy in the pipe (the stop end or gauge flying off under 10 bar with a pipe full of air would certainly blind you if you get it in the eye, or cause serious injury or break windows)
I noticed if you follow their instructions exactly and go to 10, rest for a bit, then drop back to 7 or whatever it is, the pressure will (and should) hold indefinitely. It's best to give it a few hours, or a day ahead of screeding to prove no leaks.
Watch the ends of the pipe too - if they get scratched, either laying or screeding, the o ring seal will be compromised. I have either wrapped them up in plastic or slid a bit of unslit pipe insulation over them which protects them well.
I recommend a couple of the cold forming bend adaptors where the pipe exits the screed as it holds a tighter bend and stops the pipe trying to bugger off while you're fiddling with the screed.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Saturday, 6 May 2017 20:57:49 UTC+1, Tim Watts wrote:

If I did this now I'd definitely put a diyed drain heat exchanger in. I'd also include some sort of pipes or void in lieu under the floor to harvest the coolth down there in summer. The latter need not cost anything more than junk.
NT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.