Roof

The roof construction will be one of a 'warm roof' design.  This meaning that the insulation is above the rafters, which keeps the rafters at room temperature, and minimises the chance of condensation forming and causing damp problems.

There are many designs for a warm roof, but the order from the rafters to the waterproof top are:

- Waterproof membrane (likely rubber EPDM membrane)
- Recticel Plylok 100mm (This incorporates a 6mm ply top, 90mm of insulation, and a foil faced bottom (vapour shield)
- Breathable membrane (optional I believe)
- Rafters

As the insulation sits on top of the rafters, I decided to first build the end rafters which would ride up at the ends to provide an enclosed area to sit the Insulation.  Pic of the pre-built LHS end rafter:

Rafters to be positioned every 600mm.  Currently two end rafters one one additional fixed:

The remaining rafters went up very quickly, with double rafters at the places where the 1.2m wide sheets will meet.  The pics below show the progress:

Now time to fix the roof sheets.  I am using pre-made warm roof sheets (Recticel brand) which comprise of a foil bottom (Vapour barrier), 90mm insulation, and a ply top.  these will be fixed directly onto of the rafters.  Fixing is achieved by eight 6" screws per sheet (3 sheets will cover the internal roof area).  It is also wise to run a bead of sealant on top of the rafters where the sheets will it and meet the adjacent sheet.

I should add that i added another piece of timber along the entire back edge on top of the rafters to give something for the Recticel sheets to sit up against.

Pics below of the bottom of the roof from inside, you can see the foil facing.

The Insulted roof panels are only large enough to cover the area of the roof which covers the inside of the office, not the overhang at the front.  Maybe would have been easier, but unnecessary expense and cutting, so I am covering the overhang with 5mm ply on top, a facia board on the front and soffit underneath.  The pics below show the woodwork ready to take the plywood from atop the ladder.  Once this is covered., and the facia board fitted, we can get on to fitting the EPDM rubber membrane over the whole roof.

Pic of the two new timbers fixed lengthways at the front and back of the overhang.  Note pre-drilled with 6" screws part screwed in, so I can lift it up, and finish the screwing easily.

And from the ground:

As shown elsewhere, the ply top was fitted to the over hang, as well as the cedar soffit and facia boards.  The roof deck was then ready for the EPDM top:

I'll not go into any detail on the fitting of the EPDM, as this can be found easily on any of the supplier websites.  Pic of the top - one of the front corners:

EPDM laid out before being glued:

Picture of the front before the trims were fixed: