Calculating roof pitch

Slope pitch conversion, % pitch to degrees pitch can be found here.


I’m calculating a suitable roof pitch (truss roof) to allow at least 30cm of insulation to exist at the inside of the bale wall (interior) to minimise heat loss on this area of the house. The solution can be a raised heal but alternatively the slope of the roof can be formed so that insulation can be maximised.

I just read on https://www.leroymerlin.fr/v3/p/produits/tuile-imerys-toiture-rouge-romane-sans-e46534#questions-answers-details that the Romane tile can have a minimum of 15 05 degrees pitch (27%).

I’m just going to work the numbers with a 25 degree pitch to make the roof above more shallow.

tan(25)*4.45
25-degree pitch would give 2.07 metres to the eves

tan(25)*0.95
0.44 meters at the internal edge of the bale in the roof

25 degree pitch is 46.6308%