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CostHelper > Home and Garden  > Construction & Renovation > Home Addition

Home Addition Cost

How Much Does a Home Addition Cost?

average costMedium: $13,891-$16,297high costHigh: $94,918-$122,085

Remodeling an existing home almost always costs more per square foot than new construction, because the renovation must match the existing structure, which may not be level or straight. However, a home addition can add desired space without the hassle of moving to a new home.

Typical costs:

  • Adding a bathroom by converting existing floor space starts around $3,000-$6,000 (depending on easy access, size and quality of fixtures and other amenities) but can run $7,000-$25,000 or more for spa-like master baths or projects with poor access to existing utilities or requiring foundation reinforcement. Do-It-Yourself supplies start around $500-$1,500 for a basic bathroom or half-bathroom, but can run $2,000-$4,000 or more for a larger spa-like project. Having a contractor add new floor space for a bathroom starts around $25,000-$50,000 but can go up to $40,000-$80,000 or more for a spa-like room.
  • Converting existing floor space into a bedroom as a do-it-yourself project runs anywhere from $200-$5,000 or more depending on what's involved; hiring a contractor can be $7,500-$50,000 or more. Adding new floor space for a basic 10x15-foot bedroom runs around $3,750-$7,500 for an entirely do-it-yourself project or $7,500-$22,500 or more to hire a contractor. The cost of adding a porch can range from $50-$120 for do-it-yourself materials for a simple concrete slab to $3,000-$6,000 to have someone pour a 50x20-foot slab.
  • Converting existing floor space into a family room as a do-it-yourself project runs anywhere from $200-$5,000 or more depending on the complexity of the project, the quality of the materials and your skill level; hiring a contractor for the conversion can be anywhere from $7,500-$25,000, depending on what's included. Adding new floor space for a 400-square-foot family room can run $10,000-$20,000 for a do-it-yourself project, or $30,000-$100,000 or more for an addition built by a contractor.
  • Adding a 1,500-square-foot second floor with large sections done as a do-it-yourself project (plus serving as your own general contractor when needed) can run $105,000-$225,000; hiring a remodeling contractor for the same project can be $225,000-$450,000.
  • Adding a small 10x12-foot wood deck can run $500-$1,000 for do-it-yourself materials or $1,000-$1,900 to hire someone to build it. A larger deck of wood or plastic composite can be $4,000-$25,000 or more depending on size, materials and complexity.
Related articles: Interior Decorator, Bedroom Addition, Family Room Addition, Second Floor Addition, Bathroom Addition, Kitchen Remodeling

What should be included:
  • Each city or county has its own requirements for how much square footage you can add based on the amount of land.
  • Better Homes and Gardens explains what to consider in siting[1] your home addition. gives a detailed list of potential costs[2] for a home addition.
  • Construction work can be extremely disruptive, and often involves a crew working inside your home starting early each morning, which will change your family routines. Talk with the contractor about scheduling, and when water, electricity or other utilities might be turned off.
Additional costs:
  • Usually an addition will trigger a reassessment of your property taxes and a resulting tax increase, but in most areas the reassessment will only be on the value of the addition, not for your entire house. A large addition can also increase your monthly utility bills.
Shopping for a home addition:
  • To hire a general contractor to handle all aspects of a complex addition, the National Association for the Remodeling Industry provides an online booklet with tips[3] for hiring a contractor.
  • Check whether a contractor is licensed in your state. A written contract should include a detailed outline of the work required and materials used, dates within which the project will be done, and a payment schedule.
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What People Are Paying - Recent Comments

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Room addition towards the back of the house
Amount: $50,000.00
Posted by: Ev J in Douglasville, GA.Posted: March 31st, 2023 12:03PM
Sq Ft of Addition: Which Floor: Main floor-ranch
Number of Rooms: 3
I had a room addition at the back of our ranch house (I don’t remember the sq footage), but the length from one end of the house in back through the kitchen. It was a big extension. We made it as the family room. Had a back deck built with use of composite wood about 20 ft/length & ??? width. It had lattice wrap around below the (don’t know what you call it, but it’s like window sill but without windows). They built the roof to tie in with the roof of the house. Built steps, landing, & more steps to the ground. Below the newly built extension of the house, I also had them put lattice wrap around to enclose the bottom part of the extension (since we had a basement). That also included a heat & air unit, like what’s used at hotels. They installed the wirings, lights, & fans, but I I bought 3 ceiling fans. Is that fair and good price?
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Amount: $146,000.00
Posted by: GIDDINGS CONTRACTING in Baltimore, MD.Posted: January 5th, 2019 10:01PM
Sq Ft of Addition: 1500 sq.'Which Floor: Bottom & Top
Number of Rooms: 4
Master suite, Master Bath, open 1st level, sm. office. GIDDINGS CONTRACTING: 443-474-2342
WE built a Master suite 2 story addition and they loved it. Calculating where the budget goes is the percentage int the foundation and Roof framing system. If you are interested in more give us a call, text or email: [email protected]
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Addition cost
Amount: $100,000.00
Posted by: Bhouston in Roosevelt, UT.Posted: January 20th, 2017 07:01PM
Sq Ft of Addition: 680Which Floor: Main
Number of Rooms: Kitchen dining living
I got a quote from a contractor here in Utah for a 680 sq ft addition, kitchen living room and dining. He said 100-110 k
That seems outrageous!!!! I read comments above of getting just as much for less? He was my first bid! What u think???
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New 50X17 Garage and New Insulated Siding on Split Foyer
Amount: $58,000.00
Posted by: MikeB in Fairfax, VA.Posted: January 21st, 2016 02:01PM
Sq Ft of Addition: 850Which Floor: On New Slab
Number of Rooms: 1
I contracted for a very large (fits 3 cars) long garage (due to lot size). I also wanted all new siding on the house to match the garage. Three windows had to be removed for the garage and a new 6 foot wide window unit put in the master bedroom. Garage was not finished except for the ceiling drywall (ready to paint). Siding was hi-grade CertainTeed insulated siding. Cost=$58K including footing, roofing for garage, concrete, electrical to code, etc.
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576 sq ft addition over an attached garage
Amount: $0.00
Posted by: Rpiper in Angola, NY.Posted: October 1st, 2015 06:10AM
Number of Rooms: 1
Getting quotes from contractors to do just a shell package for a 24 by 24 addition above garage. Quotes ranging from 30,000- 52,000. Seems really expensive for rough carpentry. Does not include siding. Do these prices seem to make since?
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Project tips
Amount: $0.00
Posted by: Anotherone773 in Ofallon, IL.Posted: July 15th, 2015 06:07AM
Project tips:
1)Building up is always more expensive than building out. Usually quite a bit more expensive.
2)Material is normally figured with 10-20% waste depending on the complexity of the project and type of material used.
3)Many projects have hidden cost because we run into hidden problems. These should be brought to the customers attention before the work is performed to fix.
4)If you have a budget you can spend, you should set aside at least 10-20% of that budget for hidden costs.
5) Different materials require different skill levels and time frames. Materials that are a pain to install will cost you more.
6)Make sure you have a contract that states exactly what is being performed and the total cost for all work, who is buying material, paying trash removal,etc. You dont need an itemized cost but you do need an itemized contract.
7)It is not usually better to buy material yourself. It can end up costing you more.
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Tips on contractors.
Amount: $0.00
Posted by: Anotherone773 in O'fallon, IL.Posted: July 15th, 2015 06:07AM
I have been doing carpentry for 20 years. Some of these prices here are ridiculous. Tips:
1) Word of mouth is the best way to find a contractor.
2)Dont rely to much on references( unless you know the person giving the reference), they can be easily faked.
3) 3 estimates min,as many as 6. Be wary of taking the lowest or highest especially if they are a lot lower or higher.
4)Have an idea of what you want and ask questions.
5)carpentry requires a lot of skill and problem solving. Many customers think $12-$15 an hour is a good wage for a carpenter...its not unless you want your house to fall down. Carpenters get $20-$50/hr in wages depending on skill and experience. Helpers(grunts) get $10-$18 an hour. Remember this when quoted labor.
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Room addition
Amount: $0.00
Posted by: Becka in Seymour, IN.Posted: July 11th, 2015 06:07AM
Number of Rooms: 1
Wanting a room off of bedroom for an elderly live in. Needing a small kitchenette, sitting room. A place to hav a TV windows, and a exit door to the back patio. A room about about 400 sq feet.
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Amount: $0.00
Posted by: Chris2 in Delaware Cty, NY.Posted: February 4th, 2015 03:02PM
Sq Ft of Addition: 480Which Floor:
Number of Rooms: 1
I want to have a building built as an art studio that could double as a garage if I decided to sell the property later on. It has to be heated (probably electric baseboard) and insulated, with about 4 medium-sized windows, a large French door (with framing for a garage door if I ever took out the French door) and preferably 10' walls. Other than that, just a few ceiling lights, two ceiling fans, and a bunch of outlets. Water not necessary. Concrete floor with some kind of plywood floor on top and insulation in between, and insulated walls and ceiling. 1-2 skylights. Any idea of cost? This is for rural upstate New York.
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Bedroom addition for studio
Amount: $0.00
Posted by: L in San Diego, CA.Posted: January 6th, 2015 07:01PM
Sq Ft of Addition: 200Which Floor: ground
Number of Rooms: 1
I want to add a ~140-200 sq feet to a studio in San Diego so that I can rent it as a 1bd apt. Does anyone have a rough price? I would like it to be permitted.
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Approx Home addition cost needed
Amount: $0.00
Posted by: rsracing1 in Sedalia, CO.Posted: November 17th, 2014 12:11PM
Sq Ft of Addition: 700Which Floor: ground lever + 2 story ontop
Number of Rooms: 2
Looking for approx cost per sqr/ft to build addition. Current house has concrete foundation with concrete footer foundation walls. House is square in shape ground level double garage above garage is main level home and bedrooms above that ( 2 story on top of garage)
I m looking to add a 700 sqr/ft garage to side of current garage making 3 car garage and build on top 2 story addition same as original house. Each room above the garage 1st floor and 2nd floor will be one room. So existing room on 1st floor will be made into one large room with extension. same goes for second floor. No plumbing required, small amount of Heating ducts on each floor to be extended same goes for electrical
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Amount: $0.00
Posted by: mike giddings in balt., MD.Posted: November 7th, 2014 06:11PM
Man your crazy at those prices, you must be getting an illegal, with dumpster wood, and a poor quality, real poor quality of slave labor, No one will get quality & honest to goodness building quality for that price, i think to many internet geeks & lead service chair warmers are playing with contractors web sites. True quality, not high end goes for 3 to 4 times more than your quotes from this site. signed Mike Giddings Sr.443-474-2342
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walk in closet
Amount: $0.00
Posted by: Suzanne Jimenez Diaz in Prunedale, CA.Posted: November 3rd, 2014 11:11AM
Sq Ft of Addition: 100Which Floor: first floor
Number of Rooms: 1
I would like to know (a rough estimate)how much would it cost to build a walk in closet (10x10) with built ins and a window.
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convert carport to bedroom
Amount: $0.00
Posted by: montez wiggins in athens, AL.Posted: October 18th, 2014 05:10PM
Sq Ft of Addition: 180Which Floor: main
Number of Rooms: 1
I would like to know the price to get it built. it has 2 existing walls can someone just tell me the price . and how many 2 by 4s needed
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bedroom addition to older ranch style home
Amount: $30,000.00
Posted by: rock in atlantic, VA.Posted: October 12th, 2014 01:10PM
Sq Ft of Addition: 250 sqftWhich Floor:
Number of Rooms: 1
need an estimate on adding a bedroom to an existing home built in 1965. looking for approximately 300 sqft with a bathroom included.
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room addition
Amount: $30.00
Posted by: Von in Mays Landing, NJ.Posted: July 2nd, 2014 06:07PM
Sq Ft of Addition: 20x20Which Floor:
Number of Rooms: 1
I was wondering what it would cost to have a room added. It doesn't have to be 20x20 something, you can add a bed, hang a TV, bathroom with small vanity and Shower? maybe have a place to put a small chair or couch. add a microwave, counter to put Nuwave oven, with a small sink/counter. I think 20x20 is to big for what we are looking for. i've seen small compact areas. This will only be for visiting family, it won't be used all the time.
Our budget is 30K, will we have money left over, from what I was told, 30K is way to much?
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Medium room addition
Amount: $0.00
Posted by: JenRab in Burbank, CA.Posted: March 9th, 2013 12:03PM
Sq Ft of Addition: 168Which Floor: first
Number of Rooms: one
I am a licensed contractor who has worked as a subcontractor for many remodelers here in SoCal. Most of them are looking to get rich from oblivious homeowners, and will hire illegals to do most of the work and pay them $8/hr (which they are thrilled to get)then rip the customer by jacking up costs of plans, permits and materials to pay for their new trucks, boats etc. It's shameful, thank god I can do the work myself! A medium room addition should cost under $30,000.
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farmers porch
Amount: $12,000.00
Posted by: Gi in Manchester, NH.Posted: February 6th, 2013 01:02PM
Sq Ft of Addition: 240Which Floor: first
Number of Rooms: 1
It was a rocky start but it was finally finished and it was well worth the wait
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Bath and kitchen remodel
Amount: $17,000.00
Posted by: Jill35 in Charlestown, RI.Posted: December 21st, 2012 02:12AM
Number of Rooms: 2
Jdh home improvement came and redid the kitchen and our bathroom..They were very professional and Jeremy was there actually doing the work.I would recommend this company and will definitely use them again Jdh home improvement 401-688-3639
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Add a bedroom
Amount: $12,800.00
Posted by: Larry in Dallas, GA in Dallas, GA.Posted: September 24th, 2012 09:09AM
Sq Ft of Addition: 168Which Floor: main
Number of Rooms: 1
Add on bedroom 12x16. Complete with HVAC,electric, light/fan, windows and two doors, and primed for painting. Excellent contractor with an outstanding history.
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Re-modeling and additions
Amount: $0.00
Posted by: Skilled Tradesman in Morton, PA.Posted: September 9th, 2012 04:09AM
Anyone writing on here who is concerned solely with price... don't get the work done. When work in your home is not done correctly it will present problems for the rest of your stay. I have worked with several contractors and the desparity in quality is sickening. That being said, some of the expensive guys sucked and all of the low-ball guys sucked. You really need to interview the contractor and get to know them and do your homework. Plenty of scum bags talk a good line and wear a hammer loop.
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I want to an addition
Amount: $0.00
Posted by: Kamo in escanaba, MI.Posted: August 27th, 2012 08:08AM
Sq Ft of Addition: 300Which Floor: 2
Number of Rooms: 1
So what i want to do is add a master bd/bath upstairs. It would extend over the lower lvl of the house. So what I would need the area built and weather tight. I can finish the inside (electric, plumbing, etc) and outside. The room would be roughly 20x15. Any ideas how much this would cost?
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Be mindful of contractors that quote "per square foot".
Amount: $0.00
Posted by: Brian G. in Indianapolis, IN.Posted: August 24th, 2012 02:08PM
Never, EVER, trust a contractor that only provides quotes based on the square footage being added. Not all projects are the same and for a contractor to quote based only on the square footage means they're going to RIP YOU OFF.

This is an acceptable way to get a very rough estimate, but when you actually get a quote from a contractor their estimate should include an extremely detailed list of materials, subcontractor costs (including materials) and their estimated labor hours and what the cost per hour will be. And once you've got it in writing, go over it in detail, ask questions and then have them sign a contract.
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Room Addition
Amount: $45,000.00
Posted by: researcher in Middlesboro, KY.Posted: December 17th, 2011 12:12AM
Sq Ft of Addition: 468Which Floor: rear of house/ new room
Number of Rooms: 1
First addition to my home. Can someone tell me what they think of this contract. A room addition that will be 26x18 in the rear of the house for $45,000. Built from the ground up, completely drywalled finish ready to paint, built deck ready to apply flooring, 10 windows 5ftx33'' with a door, standard electrical job with a heating and air unit (similar to one found in a hotelroom), outside will have siding, dry pipe will be redirected, entire job fully warrantied. Should I select this contractor?
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