thanks for the message
with regards to the floor ....on the width of 3.6 m i used a middle joists to add a bit of strength and remove some of the springyness.
the only dpc was where the timber was incontact with the concrete piers as it was far enough the ground to allow for good airflow.
we used kingspan under the office part of the floor, but the rest was fibre glass because of the cost....quite often homebase or b&q have it on offer ie
£3 / 1200 width roll so the insulation for this cost about 20 quid instead of a few hundred
it is messy to use sometimes but what i sometimes do is make the frames on the floor with 1 side clad then put the insulation in cover with breather membrane and batten then upright it that way .saving alot of hassle......on a pent roof we do the same ie make a couple of roof slabs and lift then on.
hope this helps
THis was a job for my nextdoor neighbour total material cost was about 1800.
the reason i use the ply wood it that it makes the frames stronger and adds rigidity and also helps keep the shape when moving them about.
the ply is 6mm far eastern I also use the ply because if lining with mineral waool against just a membrane it tends to push it out towards the cladding ....the ply stops this.
So in effect i build it tripple skinned.....plywood (strength), membrane (waterproofing) cladding ( makes it look good )
single sloping roofs are easier to build and you only get water falling the 1 side. On the inside it was lined with 9mm far eastern ply
hope this help s
anymore question feel free to ask