UFH in Dry Screed on Pozi Joists

[Jamie998]

Hey,

 

Just trying to get my head around how this would work for the first floor.  As I understand it, because the pozi joists can't be notched there are two options:

 

1.  The UFH pipes are supported between the joists with the loops running down and up through the webs.  The dry screed is then laid on top and all of this sits between the joists so that the finished screed surface is level with the top of the pozi joists.  The sub deck then gets laid over all of this.

 

2.  A supporting deck is laid over the pozi joists.  The pipes are then laid on top of this and its all then covered by the dry screed, with the sub deck then being laid over the top.  This all sits on top of the pozi joists.

 

At the minute, if I have method 2 correct then this looks like my preferred route.  Unless someone tells me otherwise, I dont like the idea of UFH pipes running down and up through the webs of the pozi joists and it seems a lot more fiddly and time consuming over just laying all of it on top of the joists?

 

Advice from people in the know is much appreciated!

 

Ta.

Edited June 5, 2019 by Jamie998

[ProDave]

Method 2 is what I did.

 

11mm OSB over the joists.

 

25mm by 50mm battens following the lines of the joists.

 

UFH pipes between battens.

 

Dry my sand cement screed between battens,

 

Sturctural timber floor over the top fixed down to the battens.

 

 

Don't forget to size the joists for the extra dead load of the screed.

[Alexphd1]

I know it's not a dry screed but I was planning to fit these after chipboard was layed for 1st floor but in the end I just used radiators.

https://underfloorparts.co.uk/product/suspended-floor-clippa-j-shape-aluminium-underfloor-heating-ffb-spreader-plate/?gclid=CjwKCAjw0N3nBRBvEiwAHMwvNvLn-1OM1MxeXkSuupeLe_NQUAaL-eVX7jUF_RdvkUesNNZfiUozzhoCufYQAvD_BwE

[Jamie998]

8 hours ago, ProDave said:

Method 2 is what I did.

 

11mm OSB over the joists.

 

25mm by 50mm battens following the lines of the joists.

 

UFH pipes between battens.

 

Dry my sand cement screed between battens,

 

Sturctural timber floor over the top fixed down to the battens.

 

 

Don't forget to size the joists for the extra dead load of the screed.

Cheers @ProDave that helps to clarify things in my mind.  I forgot about the 25*50mm battens - which answers the query about how does the sub deck attack to the pozi joists over the screed!