biscuit screed for underfloor heating on top of suspended timber floor

[Notch7]

Has anybody done this?



It is a suspended timber joist floor with insulation on top, counter battened, in screed pipes in between and then fill over with 25mm or 30mm (Im thinking of CLS laid flat which is 38mm) of weak screed mix say 1:8

Somebody suggested making the screed with a mixture of sharp sand and latex self level rather than cementitious.

 

[tomfe]

The screed is only there to help with heat distribution and retention. You could probably use use sand but it would dust everywhere.
SLC will be more than cement so just stick with sand and cement. Type of sand will make little difference.

 

[Notch7]

Hi Tomfe, thanks for the advice -would you say just enough water mixed in to allow the cement to set but as dry as possible? After all strength isnt a factor, as you say it is just there for heat distribution and a thermal store.

 

[tomfe]

Yes, use as little water as possible.
Unless your bulk bags are undercover they might be too wet as it is