Foil backed Joist Panels

[Edward]

Hi all

 

Were about to install the Rehau UFH system in our old house, which has a suspended floor, with unequally spaced joists. The sizing of the joists rules our aluminium spreader plates and because we want to keep the FFL the same, we have decided on foil lined polystyrene panels in between the joists. Our builders are currently insulating the floor with Rockwool prior to the joists being installed. I have two questions:

 

1) There appears to be a few different type of foil lined EPS joists boards on the market, would you recommend one over another and if so why?

2) I am slightly concerned about the conduction from the foil backed board up into the floorboards - there is a chance of a small cold bridge here, would it be worth packing the interface between the EPS and the floorboard out with a conducting material to ensure there are no air gaps?

3) Finally is the type of tile on the floor important as we are most likely to use a porcelain tile.

 

Many thanks

[nod]

There’s not much between the insulation sheets Some are slightly cheaper than others Kingspan is as good as any 

 

Any of the Porcelain tiles are good with UFH 

[A_L]

5 hours ago, Edward said:

2) I am slightly concerned about the conduction from the foil backed board up into the floorboards - there is a chance of a small cold bridge here, would it be worth packing the interface between the EPS and the floorboard out with a conducting material to ensure there are no air gaps?

 

Rehaus's own metal diffuser plates are 0.8mm thick. The heat conduction along the foil covering of an insulation board will be insignificant by comparison. Cooking foil is 1/50th as thick as a metal diffuser plate and I am sure thicker than insulating board foil.

 

Consider surface mounting the pipes on insulation board and use a sand/cement 'pug' mix between the pipes to spread the heat