Wet ufh screed

[Ajax123]

Sureflo sounds the one, I don't have meters and meters to justify ready mix,, I know ccf well and will talk to them on Monday,
cheers Ajax

You might struggle with your local CCF. If you do ask to speak to Matthew farmer at the Leeds branch. Tell him Alan Jackson sent you...

 

[Rossymcg]

Ajax another question,
could I use the sureflo with the 100mm joists having 75mm Kingspan in between the joists, pipes on to the Kingspan then the sure flow at a depth of 50mm covering the pipes in between the joists and 25mm on top of the joist height?

 

[Chalker]

Ajax another question,
could I use the sureflo with the 100mm joists having 75mm Kingspan in between the joists, pipes on to the Kingspan then the sure flow at a depth of 50mm covering the pipes in between the joists and 25mm on top of the joist height?

you will still need the fermacell to decouple from the joists expanding.

 

[Ajax123]

you will still need the fermacell to decouple from the joists expanding.

Not necessarily. If the joists are covered then the screed effectively becomes an unbonded screed.

 

[Ajax123]

Ajax another question,
could I use the sureflo with the 100mm joists having 75mm Kingspan in between the joists, pipes on to the Kingspan then the sure flow at a depth of 50mm covering the pipes in between the joists and 25mm on top of the joist height?

You might get away with 25 mm cover to the joists but I would aim for 30mm personally to minimise any risk of cracking.

 

[Rossymcg]

You might get away with 25 mm cover to the joists but I would aim for 30mm personally to minimise any risk of cracking.

Yes 30mm is no drama, are you saying I should also put a dpm covering the insulation and joists to decouple the screed from the insulation and joists

 

[Ajax123]

Yes 30mm is no drama, are you saying I should also put a dpm covering the insulation and joists to decouple the screed from the insulation and joists

Yes. This will provide what is called a slip membrane and will also help to keep the screed on top of the system avoiding any leaks... Bear in mind it will be a liquid screed when you pour it. Clip the underfloor heating pipes to the insulation between the joists. How much space do you have available over the joists. If you have room you could overlay the joists with a 15mm OSB deck screwed through and put the screed on top of this. You would need 40mm in that instance so total 55mm over the joists. You would then have a composite floor and no need to notch the joists to allow the pipes to pass across them. Just adds a bit of flexibility to your design but obviously reduces the floor to ceiling height.

 

[Rossymcg]

It works out seriously expensive using the sureflo , I know I can't talk prices but at the cost quoted per bag and needing 80 bags just for one room, not a viable option,