The transition from doing the work to bidding the work is the question. No one will dispute that the times are different from just a few years ago and you'll find alot of men/women willing to work in the cold vs starving. That said working in freezing weather takes its toll and does take longer. Most factors that I've seen add about 50% to the original time necessary for a task in extreme weather equalling a 1.5 X factor.
I'd also be concerned that you're sub for the concrete work has that covered as pouring & curing concrete takes a controlled enviornment, and it's tough to dig or trench in frozen earth, if he folds your completion bond is what they'll come after.
Reading between the lines was the project start delayed? Or did it bid more than once?
I mis read the question. I took 'labor increase' to mean wages per hour, not hours needed.
You not only need to figure for lags due to workers not being as productive, but the fact that wire is MUCH harder to work with when it's cold. I have personally seen the insulation on THHN shatter when the conductor was bent enough to land in a meter base.
In deep snow, simple logistics become a nightmare.
Cordless equipment will discharge faster in sub zero weather, and take longer to re-charge.
Vehicles will be more expensive to keep operating and will suffer a higher indecent rate of starting failure when it's cold.
Accident rates will increase as slip and falls are common here during the winter.
Colds and the flu will take it's toll as the virii are spread from person to person in the closed quarters of the break trailers, offices and porta-loos.
Lateness and absenteeism will increase due to auto accidents. Ice in the winter and deer in the fall take out their share of work vehicles here each year.
Opening day of firearms deer hunting season is so popular here that many shops close right up. Expect a substantial portion of the workforce to be absent on Nov. 15th of each year.
I would say 50 percent, as mentioned is not unreasonable. Some years it may take less, some much more.
I always wondered why the powers that be schedule outdoor work to be done here in the winter.
One year we had to put in a huge buss that ran down the outside of a power plant which was on Muskegon Lake, near Lake Michigan. The temp was 35 degrees, we had freezing rain and 35 mph winds for the four days we were there. The buss had been bypassed four years prior. There was no reason to not do that job during nicer weather, but that's the way they scheduled it.
I worked for a new EC in Shelby one winter on a re-mod. It was so cold inside (no heat, open walls) that a bottle of water would not last from start to first break without freezing over. The EC couldn't figure out (from the warmth of his truck) why it was taking longer to rope the house than he had figured.
I stopped trying to figure out the logic of scheduling outdoor electrical work in Antarctic conditions when a shift of just a few weeks would make all the difference in the world to the worker's productivity, safety, comfort and attitude.