Floor temp for radiator sizing

[Fredxx]

I'm struggling to find a reference to the floor temperature and how to calculate heatloss though the floor.

I have, through a link on the diyfaq:

a link: but that assumes a temperature difference for the floor of 27C which can't be right.

I don't seem to have joy with other links on this page:

to 404 not found,

to DNS error

to their home page.

Does anyone have a reference link for u-values and prospective ground temperature?

Many thanks

[Jeff Layman]

Anything here of use?

(it refers to a concrete floor U or 0.7. It also uses an internal temp of 20 deg and external of -5 deg, giving 25 deg in total, which wouldn't be far off your 27 Deg)

[Fredxx]

Many thanks.

Both of those links refer to ground temperature as being the same as external air temperature.

There has been some more recent interest in soil/ground temperature with the take-up of ground source heating and these suggest a minimum temperature of 6C 0.5m below the ground.

I am assuming my floor is a solid raft with no insulation so any more critical on temperature.

So far I'm assuming a 15C temperature difference for the slab, but not sure if the U-factors for floors are fudged to include this.