Fitting the fascia, soffits, and other trim is simply (!) a matter
of dogged carpentery
There isn't really anything clever or subtle about constructing the
fascia and trim -- it's just a case of getting out your saw, tape
measure, and a stack of timber.
The fascia boards (the bits the hold the guttering) go up first,
because they fasten directly to the ends of the rafters. If you've
cut your rafters properly, the ends that hang over the wall plates
have a vertical face for fastening the fascia. The soffits (the horizontal
wooden boards) then fasten either to the fascia or the rafters.
The rest of the timber trim pieces were then individually measured
up against the building itself, because I didn't want to have any
big gaps between the pieces, and my construction up until this point
had not been perfectly accurate, you'll probably not be surprised to
hear.
The barge-boards (the wooden trim at the front) are interlocking
tongue-and-groove boards, designed really for shed cladding. There is
a `right' way to fasten these boards, so water that blows against them
is shed, rather than oozing into the joints.
The trim at the gable (front) end hides the ugly gap between the
roof tiles and the ceiling plywood. Conventionally this would be
done with mortar but, the way I constructed the roof, I think the
mortar layer would have had to be really thick (ugly) and heavy
(and we don't need any more weight on the roof). A wooden board is
relatively light, compared to a four-inch thick layer
of mortar, and doesn't look as ugly. The gap between the
tiles and the gable timbers is sealed with yet another thick plug
of bitumen.
It's quite difficult to paint whilst up a ladder, and some of the
timber is tricky to get to. So I primered and undercoated all the timber
on the ground before putting it up. The only problem with doing this,
particularly in the Autumn, is that debris (falling leaves, dead
bugs, etc) tends to blow onto the paint while it's drying. But I
think it's still easier and quicker to do things this way, even though
the painted timber still needs a bit of sanding before the top coat
to get the grot off.
Because the porch has an apex roof, drainage and guttering is required
on both sides, which is a nuisance. I've noticed that some builders
run guttering all the way around a porch, and therefore only need one
drainage downpipe. I think this looks rather ugly, but I guess that's just
a matter of opinion. In any event, I needed to install two downpipes
to carry away the rainwater. The guttering worked out surprisingly
expensive, because of the number of bends and couplings in the
pipework.
