Mr Kevan Gunn
RE: Your Opinions welcomed regarding a Claim being made against me
"The reason it is contractor's design because he can schedule his works as far it suits him with laps to suit his pours. It is difficult with the designer who does not know his sequence at the start of the project and the contactor start complaining afterwards."
There is absolutely nothing to stop any consultant producing a layout for roof trusses, timber kit, steelwork, rebar to floor slabs and beams by assuming a work sequence that is sensible, then allowing a contractor to modify it for his personal sequencing. In fact, the first question any designer should ask is "how will I build this?" the second one is "what does that mean to my design process"
The concept that time spent on this is "abortive" is pure nonsense because the "abortive" work is what the rest of the design is based on.
looking back on a wall design to see if a proposed roof design by a contractor is okay is a lot more confusing if you havent got a design for the roof that the wall design was based on!
In terms of this claim, It is truly non-existant and the OP should never ever have indicated to entertain anything of it. I would even suggest backtracking even now and saying that on reveiw you withdraw any indication of supplying a refund and state the client should never have entertained the contractor's claim either. An error is an error and should be drawn to the designer's attention as soon as practical and with sufficient warning for a response. The action of the contractor was insufficient in warning and there appears to be a massive inflation of cost. I suspect that the contractor was rushing headlong into a pour and ordered concrete before completion of the fixing and perhaps even starting! His error of foolishness trumps the design mathematical scheduling mistake