u value?

Espoo

Hi
Can someone tell me the u value of a mass concrete wall built in 1939 with 38mm thermal board on the inside and skimmed? I assume you add the resistance of the default value for the mass concrete wall itself to the resistance of the thermal board and divide 1 by total resistance? Ya don't need to worry about surface resistance? Do ya? What about external render on concrete wall?

Also What is the default u value of a 2003 built wall drylined. wall is 450mm thick. Thats all i know

Cheers

sydthebeat

Espoo wrote: »

Hi
Can someone tell me the u value of a mass concrete wall built in 1939 with 38mm thermal board on the inside and skimmed? I assume you add the resistance of the default value for the mass concrete wall itself to the resistance of the thermal board and divide 1 by total resistance? Ya don't need to worry about surface resistance? Do ya?

thats generally it.

you dont need to worry about surface resistances as they are included in the original default resistance.

you include them if you want to calculate the actual u value, which would need to be backed up with evidence.

if there is a new extra external render, you can include its resistance as well, though it will make minimal difference.

Espoo wrote: »

Also What is the default u value of a 2003 built wall drylined. wall is 450mm thick. Thats all i know

check DEAP manual table S2
typically 0.37

if its 450mm thick it may be worth your while trying to determine the exact make up and calculating the u value.

Espoo

Thanks Syd
Yeah I've to go back and check a few things on this batch of appartments
so was guessing the thickness to be about 450 for now. It does seem as if there is something worthwhile in there checking as you suggest.

cheers