here's a new one - thatch roofs?!

[vic_in_scotland]

Hi all,

Still doing domestic buildings in IES (it's research), and I've got to put on a thatched roof.
Typically you don't get thatch roofs for non-domestic buildings, so it's not in the system materials. (Although I know a couple of thatched buildings now used as offices, intriguing.)

Can I import it from somewhere, or can I create a new material, using conductivity, heat capacity information from elsewhere?
I'm assuming there would be issues surrounding a thatch, as it's so deep (the one on this property gives shading of 60cm beyond the dormer windows) and is essentially one material.

Thanks,

Vicky

[PCully]

Hi,

For whatever material you are trying to represent it's always the same kind of approach if there is nothing available in the predefined system database then you just have to approximate as best you can and try match thermal properties of the materials.

We've sent this before which may or may not help;

To simulate a thatched roof you can create this construction in the construction data base manager and change the emissivity & absorptance values to suit. CIBSE guide A has the following information for creating a Thatched Roof.

In order to achieve a ‘U’ Value of 0.2w/m2K for thatch:
Reed = thermal conductivity 0.09, and ‘r’ 11.1
Straw = thermal conductivity 0.07, and ‘r’ 14.3
This gives a ‘U’ Value of 0.2w/m2K for the following thicknesses (thatch alone) Reed 450mm and straw 350mm.

[vic_in_scotland]

Thanks Phil!