Hi peter i think i have this right you will need approx 29sqm of stuff to cover the walls
or to be exact 28.285 sqM.

i converted the ft into sqft then that into sqm
so 13ftx7ft is 91sq ft = 8.453sqm
and 12.5ftx7ft is 87.5sq ft = 8.128 sqm
and 2 9ft x7ft is 63sq ft = 5.852 sqm
i really hope im right Rob C???
sorry i forgot to do the roof if no one else has will try to do it later going out now x


1 square foot = 0.09290304 sq meters