On 05/06/16 18:44, DICEGEORGE wrote:
A new inside photo of joists temporarily resting on purlin is now at:
http://stonehengecampaign.org.uk/psi...-on-purlin.jpg

I will also add a new support for the flying end of the purlin,
which is at the moment nailed upwards.

When the joists are safely sitting on the purlin
I will probably nail them to the sloping rafters.

I believe nails are better than screws as they can be removed
if and when the roof is reslated in another hundred years.

[george]


I was going to say that - well, screw then to the rafters, with a couple
of corrosion resistant 6mm screws (self drill and/or pilot holes as
required).

I would not just sit them on the purlin - you are loading it the reverse
way to what it was designed to do - and your new rafters will try to
pull it off the old rafters.

In fact I would consider running a new beam on the top of the old
rafters to the load is going the *right* way.

Screw the new beam into every rafter.