Thanks. At the moment the rafters are only 3 x 2's albeit =on 12" centres which is probably why its sagged. They'll be replaced with either 4x2's or even 5 x 2's which will allow me to push them out to probably 18" centres, the ridgeboard is a bit of probably 1/2" or less T&G, that'll be probably 6 x 1 timber to give us a bit more strength up top. The purlins in the two car bays will be replaced with two steel I beams, one end will sit on a 9" internal brick wall, the other end will go 4" into the gable end wall and I'll either need to build a brick pillar for more support or possibly a box section steel upright under it. Rafters will then be birdmouth cut over the purlins.
We will be turning the two car doors into one large one with box steel uprights and a steel I beam over. The roof will then kick up from the purlin to the I beam over the doors at a shallower pitch than the rest of the roof so I can increase the height of the doors by a couple of feet to 8" as they are too low to get either of my vehicles in at the moment as the floor rises by a good 6" inside as well as the doors only being 6". New doors will then need to be made, wooden barn doors, side hinged and possibly bi-fold.
The rear roof is totally goosed, it's clay tile rather than slate at the moment, many of which are totally perished, theres also a good chunk at the bottom thats been really badly repaired in slate. The roof timbers are all rotten at the ends and full of woodworm. (at the back they've also been eaten away to form a rat run when it was a cowshed) Theres a valley at the back where the roof of another outbuilding meets it and thats going to get a big box gutter to catch the rain water from both whcih will involve cutting the last 6" of the other roof off (corrugated fibre cement sheet) Theres some brickwork repairs needed to the top of the back wal whcih I'm going to try and do before the roof comes off. We will also get the steel beams in to replace the purlins first simply by putting them alongside the old purlins.
Keeping the character is a tough one. I'd love to keep the brick floor inside BUT its only half there, its very uneven so hard to roll jacks etc on, you lose small screws etc down the gaps and it's horribly damp. It will go to be replaced with concrete. The walls will remain brick, probably whitewashed with a traditional lime wash so it breathes and lets water evaporate. I'd like to insulate and board between the rafters to keep the look of the roof. Once it's more watertight then I can properly do the electrics.
I think the roof is going to get done by me and some friends but it's a big job, 80m2 of slate in which I want to fit two or three velux skylights and a chimney for the woodburner. Every bit of timber from wall plates to ridgeboard will need to be replaced followed by felt (tar paper) battens and then slates, not to mention constructing the dormer over the doors.
It's a toughie though as my budget is pretty limited so its going to get done bit by bit.