It depends on the complexity of the design and what's being done, not just square footage. He's telling you "average" time, but it could be longer if you have special requests for things that aren't average.

Based on our house, I think the estimate is reasonable. Our house is significantly smaller than yours-- 2400 sq. ft. and the plumbing began before the roof was on. Our plumber started June 28th, and now the plumbing rough-in (including HVAC ductwork) is about done. The plumbing needed to be done before the electrician got started (I assume this is because it's easier for wires to work around pipes & ducts than the other way around). The electrical rough-in should be done this week. They still need to pour concrete for the basement and garage floors and put in insulation before they can sheetrock (and obviously we need a floor in the basement before they can bring in the furnace & water heater). If they are sheet-rocking 6 weeks after the plumber started, I will be thrilled.

FWIW, we have been told we can probably move-in 60-70 days after the sheet rock is complete. Originally we also hoped to move in in August, but now we're looking at October. Hopefully before snow flies.

Thanks so much for the replies. We don't have a very complicated design for mechanicals. Just the basics - probably more outlets than most because I am done searching for one. The plumbing rough in is done. Electrical and hvac have been hard at work for the last week.

We have figured out why it is taking so long to put on the shingles, we have a roofing crew of three. They only work until 2 if it is over 80 degrees because "the shingles will rip".) I don't want them to work when it is too hot, but half my town recently lost their roofs when a major hail storm came through with softball size hail and every crew was at least 8 workers that worked until 5.