Hi Peter C,
I read robster1's contribution as a rough schedule of materials and labour prices, not a schedule of works or details.
I think robster1 is covered by his suggestion of using a skilled labourer, since most of what you describe are classed as "builders details" or "roofers details".
Robster1' stated that his was only a rough guide, so lets look at what's omitted from the comments you made.
10' x 10' is the internal dimension of the space.
A flat roof will have an overhang of say 200mm 0r 8" and the walls will be 225mm or 9".
The total width of a three sided roof is 10' + 9" + 8" + 9" + 8" or 10' and 34" or 12' 10"
In addition there will be the 3 soffit boards, each 200mm or 8' wide with short sides of 10' 9"
There will also be the fascia boards to weather the top to the soffit.
Firring pieces are required to give a fall.
Even that is only part of the detailed specification.
Part of the work is demolition and carrying away - the labourers time assumes this.
Part of the spec is mechanical fixings - nails and angles- which are required to build the roof.
When you look at building works in this detail that you realize the work done by a Quantity Surveyor
It might be useful to see part of a redacted detail specification for a small job for one of our Quantity Surveyors.
ONQ.
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All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.