I don't have any clue and I really doubt that you'll be any useful numbers here since there are so many factors that would come into it, but I just wanted to say that whether you expand 6 feet or 15 feet, the cost difference won't be that much different. So you might want to consider making the addition bigger.

Greg - Thanks for the reply. I ddin't realize that adding that much more space wouldn't increase cost much. Thats good to know!

Ryan-

It is true that there are some fixed costs in any project that are moderately independent of the job, but expanding out 12 feet instead of 6 feet is going to cost a fair amount more...not twice as much, but maybe 80-90%. Tell any contractor that you assume the cost of doubling the size of a project "won't be that much different," and you'll get a reality check.

NY is a large state covering many different cost of living area's. Anything more specific?

We are in the process of extending over an existing 1920s' sunroom with existing foundation without fixtures, lights and finishes it is 360 per square ft. After finishes and cabinets we are at close to $500+ SQ FT. I live on the Ct coast within a metro north commute to NYC so an expensive COLA area. I can show our build estimate, the design estimate was low for my choices....

A middle of the road nothing special master suite 2nd floor addition runs 110K +-COLA. The bath fixtures plumbing portion, and foundation reinforcement for a live 2nd floor load is where most of the money gets flushed. It's the hard part. After that, adding more length isn't much.

Thanks for the answers everyone.

Got our first estimate this morning... $19,000 + cabinets and fixtures.

...And that's for how many square feet?

@Kudzu9 --- That is for approximately 150 sq feet of living space (there is more if you include the exterior wall).

That is about $125/sqft, which is pretty good in many areas these days. Good luck with your other bids.

That is too good to be true from anyone anywhere. Unless it's some uninsured unlicensed hack who isn't dealing with the live load issue or the plumbing slope issue, or the HVAC issue, or electrical issue. That is a 100Kmchange order and a red tag from the city. Cost vs. Value

In places like San Francisco, yes; in some other parts of the country, no.

I don't think @Sophie Wheeler knows what she is talking about. Her 100K price tag for a 150 sq addition is ridiculous and way off mark. I'll be surprised if we get a single bid over $30,000. But I guess we will see - 3 more contractors are booked to come give an estimate. All with A-Ratings from Angieslist.

Thanks @Kudzu -- I thought it was a fair price as well.

My daughter just got bids on a kitchen remodel that ranged from $11K to over $30K, and the cheapest one was the one who had multiple stellar reviews. It's great that you are getting four separate bids.

Wow that price is unbelievable! I am posting the estimate with the company we have chosen to work with and all other quotes were within a thousand up and down of this quote. Just simple framing for my 103 ft addition will cost almost 20k and the trench for waste, in and outside plumbing, electrical will almost double that cost. I have not finalized all finishing choices yet but my shower choices alone are another 10k. If you are in the metro area I would love to meet with your contractor to get a quote on my next project.

here is a copy of my choice estimate.

Phase 1 Pricing For Master BathItem Type Description QuantityUnit PriceAmount

ServiceTrench1.00 $4,400.00

Service exterior Plumbing1.00 $1,100.00

Service electrical- Material and labor to rough in and finish master bath. Owner to provide fixtures and fan.1.00 $3,200.00

Service plumbing- Materials and labor to rough in and finish plumbing. Owner to provide fixtures and faucets.Heating - Materials and labor to install Pensotti Panel Radiator DD24DBL. ( Heat loss estimate was unfavorable for radiant floor heat ).1.00 $8,360.00

service framing , roofing, siding. Including labor, materials and 2 windows.1.00 $19,500.00

Estimate Total

$36,560.00

this 36k is phase 1 of my build... And my design fee is not included for we paid for plans before going to bid. We are saving on a few windows for the builder will use some he needs to remove on an adjacent wall in the new build.

roarah-

What part of the country do you live in?

I am on the Connecticut shoreline within a metro north commute to NYC similar area as OP. I think his bid might be just structure and I admit that we will be paying $55 per sq ft more because we are putting the bath on the opposite side of existing plumbing but that comes to only $ 5,500 more than hooking into an adjacent existing bath.

Tell any contractor that you assume the cost of doubling the size of a
project "won't be that much different," and you'll get a reality check.

It greatly depends on the size of the original project. I expect that you'd agree that pushing it out one foot as opposed to two feet "won't be that much different". That's doubling.

6 feet vs 12 feet might be more of a difference, but with part of the addition being a bathroom, I figured that the fixed cost of all of the plumbing etc would be a greater factor than the variable cost of the additional square footage.

I wouldn't think you'd be able to renovate an existing bathroom for the price that the first person quoted! It goes to show that prices vary so much depending on location.

My main point was that he should consider going bigger and find out actual prices. Don't get locked into a certain mindset based on possibly false assumptions.

Granted, I should have said might not be instead of won't be. There are too many unknowns in this situation to make any kind of absolute judgment.

Just got the 2nd and 3rd estimates.

2nd contractor was at $30k completely finished.

3rd contractor told me he has a minimum job requirement of $40k, and that he could easily do the job with that price.

minimum job price though? Odd

minimum job price though? Odd

If someone's busy enough (which usually means they're good), they can be more picky about the jobs they accept. Smaller jobs don't usually have as big of a profit margin.

Just curious if you asked any of them about going bigger? Or is the size that you are looking at a more appropriate size and you don't actually want it any bigger?

@Greg -- Did not ask any about going bigger. To be honest, the level of detail they were talking about and I was trying to understand was too big as it was!

Those sound like really good numbers for structure! We're in Massachusetts and got a quote for 54K for a 10x20, double storey with full 8ft basement and a new bulkhead, connected to the current basement area with the existing bulkhead door, weather-tight shell only and a 8x12 gable roof. None of the following are included in the quote: plumbing, electrical, heating, windows - to be purchased via dealer who will supply and install them, insulation, drywall - walls or ceiling, no interior or exterior paint, sub floor only, white aluminium siding (to be painted by owners - us)

I can't speak for the cost but be sure to check your local zoning/building code before you throw any money at the project. In a lot of areas bedrooms or even portions of them can no longer be built over a garage. Whether the master bath would count as part of the bedroom I have no idea.

@Ryan did you ever get this project done? What was the final outcome and do you have pictures??