some advice on building a lean to shed please

godathunder

hi all, my first post so please be gentle

Im building a lean to shed (approx 3mx1m) outside my kitchen. the plan is for a 3 compartment block built shed housing an oil c/h burner, bin store and toilet/sink. space will no doubt prove somewhat tight but it all just about seems to fit.

Im planning on using a single skin of 6" blocks externally and 4" blocks for the two internal walls. the roof will be of pitched slate. the shed will be built into a corner so will comprise a new 1m and 3m wall with the other 2 walls formed by the existing structure

my query regards the depth of footings required

from what Ive read Im going to need to dig a 900mm deep trench with 450mm of concrete to form the foundations. this seems a little overkill given the size of the shed. could I get away with a 650mm deep trench and 350mm of concrete.

also I have a large amount of granite hardcore here (pieces are c100mm irregular cubes and smaller) would there be a problem in adding this to the concrete as bulking material?

another issue that is going to rear its ugly head is how to connect the toilet and basin wastes into the existing ceramic foul line that passes under the corner of the shed. still, one thing at a time

thanks in advance

ger

BryanF

we Can't answer structural queries - refer to forum charter