Also may depend on the age of the roof,also on the state of the supports
in between the main supports.
Brian

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"Andrew" wrote in message
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On 09/04/2021 13:22, David wrote:
I'm trying to work out what weight can be safely put on timbers
supporting
a shallow sloping roof.

I potentially need to get up on the roof to service the plastic covering
and also the flashings at some points.

My embryo plan is to construct some crawling boards which won't slip
(essential) and will carry my weight (around 168 pounds) and some tackle.

Possibly 2 or 3 boards so I can work my way along from board to board.

First I need to know if the timbers will support my weight, though.

Cheers


Dave R




Add a temporary purlin below along the middle of the span and some
temporary braced or vertical supports.