Bathroom refurb - wet underfloor heating

[xr4x4]

Hi all,

I'm starting a bathroom refurb, the whole thing is being re-jigged, pipes moved etc.

The whole house has wet underfloor heating, including the bathrooms, this will be the first time I have dealt with wet underfloor heating.

Under the floor covering there is what looks like 8x4 sheets of ply nailed down.I need to cut this up to re lay pipes etc...

What can i expect to find? What depth will the pipes be etc?

Thanks in advance.

 

[dilalio]

Well... A wet underfloor heating issue, I was once called out to, revealed a single panel radiator on its side, buried in the screed, so you're guess is as good as mine!

 

[xr4x4]

Well... A wet underfloor heating issue, I was once called out to, revealed a single panel radiator on its side, buried in the screed, so you're guess is as good as mine!

Lol

Great thanks..!

I'm pretty sure it's not this.

 

[dilalio]

As was I

 

[muggles]

If it's upstairs, the heating pipes could well be attached to the ply, so cutting through it will cause a leak. It's impossible to say without knowing what system is installed though. Some systems have pipe that is routed into timber, some have pipes under the floorboards, but all will have the pipes very very close to the surface and so you're cutting into it at your own risk. Time to rent a thermal imaging camera and cut a hatch where there definitely aren't any pipes so you can see what you're dealing with

 

[xr4x4]

If it's upstairs, the heating pipes could well be attached to the ply, so cutting through it will cause a leak. It's impossible to say without knowing what system is installed though. Some systems have pipe that is routed into timber, some have pipes under the floorboards, but all will have the pipes very very close to the surface and so you're cutting into it at your own risk. Time to rent a thermal imaging camera and cut a hatch where there definitely aren't any pipes so you can see what you're dealing with

Ar$e

 

[xr4x4]

Ok, so floor been up today.

House was built 2005.

They have put 50mm Rockwool installation on top of plasterboard of room below, then plastic pipe clipped 15mm poly pipe to the sides of the joists at the top.

Joists are at 400 centres, so two pipes are run very close, then 400 centres.

There was 18mm t&g ply boards on top, with 8mm ply over that with vinyl tiles over that.

 

[dilalio]

That's not the best of set ups... I would suspect you can feel the hot spots (runs) as you walk across the floor!

When we do UFH on suspended floors with 6" joists we use 4" kingspan or celotex, braced between the joists with nails/battens. The polypipe then gets clipped to the celotex with pipe staples and is run at one loop per joist span with approx 200mm centres. We then dry pack screed over the top to level of the joists, to allow the heat to radiate through. 18mm ply goes over this.

I have not done upper floors though, but cannot see why this method would not work... Given that some allowances would need to be made for light fittings, wiring etc for ceiling below!

 

[xr4x4]

Image

• xr4x4
• 4 Nov 2015

Grey pipe.

 

[nortonj]

I am surprised that even works, strange set up.

 

[xr4x4]

Whole house is zoned, with all rooms with own stats.

Whole upstairs must be done the same way.

Customers not complaining but hasn't been there long.(months)

 

[Tipper]

You could replace with slotted insulation boards into which pipes at 200mm centres are laid.
We used Hep2O (was sold as Wavin Thermoboard) overlaid with ply and flooring and it works very well.

http://www.wavin.co.uk/web/solutions/heating-cooling/underfloor-heating.htm

 

[dilalio]

Make sure all those push fittings are done up while you have the floor up!

And watch you don't "miss" the joists by 5mm when securing the floor back down