Timber Frame Construction
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Hi,
Sounds like you had a contractor that had other problems than just knocking this building together. Most firm that do this sort of work are pretty well organised, have done it so many times and dont cause to many problems.
For rates all depends on the complexity of the structure, but for a "bog" standard job, try using 60-70 manhours a tonne for the prefabication work. Onto which add(?) a value for the surface protection i.e blasting/painting/galv.
For Erection of the main Structure try 20-30 manhours a tonne, again all depends on complexity of structure. For items such as supports, handrails try 200 manhours a tonne. This would be for a bolted stucture.
What I normally do is work out the tonnage (approx), apply the rates, this gives me my manhours for the job. I then assume a resonable crew size/mix i.e. couple of riggers/slingers, couple of steel erectors and a crane Driver and then calculate the duration for the work.
If it "feels" ok, i.e. would I like to be doing the job in that time I will use this estimate, if not I move up the rates etc., its that old "gut feel" thing.
Regards
John