On 22/05/17 16:29, GB wrote:
On 22/05/2017 15:57, Tim Watts wrote:
On 22/05/17 13:34, Bob Minchin wrote:

I reckon this is a non starter for 2.5m ridge height. Note that the
wiki article shows a flat deck on which the beams bear. this is
critical to the strength as it will be in tension to support the roof
weight. Even if you replaced this with horizontal joists they would
end up around chest height.
If you want to stay within PDR then there is little option but to have
a very very low pitch roof

I'm starting to think you're right Bob.

The old church builders wanted to avoid beams halfway up the height of
the nave. Besides that, they were building in stone, which is not good
in tension. Their solution was buttresses, and a similar idea would work
with your shed. (Not seriously.)

Basically, Tim, what you are gradually working out from first principles
is why most sheds have a roof with a very low pitch, and covered in
roofing felt. It's simple, it maximises internal space, and it's easy to
build.




But not the felt - I hate felt...