Walked in to bid a kitchen/recroom addition last year.Four kids,3 under school age,living in a cramped ranch house.
Hardly a place to walk through,toys,clothes,books,DVD's all over the floor.
Garage and cellar full of crap,nothing organized,just in piles.
Added 50% to profit line for PITA.
First phase went great,never opened the addition to the old house till the new rooms were completed.No stairs for the little ones to get in.
This is going too good.Right on schedule.Going to make some good $'s.
Well the electrician and plumber had to clear tunnels through the crap to do their work in the cellar.It reflected in their final costs.Can't blame them.
Second phase after opening to house,three rooms,opening doorways wider,moving laundry room,new floors was a nightmare.
Kids in the way all day...,sweep up a pile of debris,go to get a barrel,....someone came in and spread it all over the place.
I had to keep reminding myself of the bottom line.
Kids uncontrolable all day,get a room cleaned out to work in....next day full of
sh@t.
Bottom line,bottom line.....
Even the new addition was a complete disaster after a few days.
None of us looked forward to working there so that hampered production.
Well,that's half the story,I won't bore you with the rest.
In the end the Bottom line was right where it should have been if I bid a regular price where I didn't have to deal with the mess.
It's tough to gauge all the things that may inhibit your production,even with an iron clad contract containing clauses for hold ups.
In the end,even with the right clauses,you end up making an educated guess about the overall working conditions.
Making a read on the client's property,and how it's kept up is a good start.
Number of kids at home,are they watched well.Is there a room away from your work where they hang?
The conditions here easilly doubled my time on part of this project.
So to the OP I say,
Consider everything,and add alot!