Search thousands of topics on

BROWSE ALL TOPICS >> appliances babies & children  cars  consumer electronics health & personal care home & garden personal finance  pets  schools small business weddings
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
post E-mail post Post   Comments (65)

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, as well as contractor referrals[4] .
  • Check whether a contractor is licensed[5] in your state, and whether there are any complaints with the Better Business Bureau[6] . 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.
post E-mail post Post   Comments (65)
CostHelper News

7 Fireplace and Wood Stove Safety Steps To Do This Week
Gathering around a wood stove or fireplace on a cold winter night can be wonderful experience, but it's crucial to not take basic safety for granted. || Posted November 12 2013

The 4-1-1 on Flu Shots
There are 13 different CDC-approved flu shots available this year. Do you know which one is right for you?To be fair, one is actually an inhaled spray, not a shot, but it is one of the choices. It's restricted to people between the ages of 2 and 49. || Posted November 4 2013

‣ All CostHelper Blog Posts

What People Are Paying - Recent Comments

Page 3 of 3   -   << Previous   1   2   3   

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?
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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
Was this post helpful to you?   yes     no Report prohibited or spam
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
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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?
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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
Was this post helpful to you?   yes     no Report prohibited or spam
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
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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?
Was this post helpful to you?   yes     no Report prohibited or spam
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.
Was this post helpful to you?   yes     no Report prohibited or spam
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?
Was this post helpful to you?   yes     no Report prohibited or spam
addition after gable end
Amount: $0.00
Posted by: Lim in fremont, CA.Posted: August 26th, 2011 03:08PM
Sq Ft of Addition: 300Which Floor: 1st
Number of Rooms: 1
I live in Fremont,CA.
In between gable end and my neighbor fence have huge space(18ft) which I currently have plastic shed.
I want to extend living room and want to have one room.
it'll be looked like following drawing.
Imagine square is my current house, and * is fence, and || stucco wall, | is drywall.
Right side will be my addition
current ---------> addition
+======|| * +=============|| *
| LR || * | LR || *
| ----||<18ft>* --> | ----+-----|| *
| kitch|| * |kitchen| room|| *
+======|| * +=======+=====|| *
backyard backyard
So, it's pretty simple addition from construction stand point of view since it is on the ground level and it is same direction in that of existing ridge board, no plumbing involved and a few electrical work.
In the room, I want to have ceiling light, window(of course) and sliding patio door out to backyard, and storage room. Of course a couple of outlet should be available to function as a room to use TV, PC...
In the extended living room, I want to have one ceiling fan.(there is already one but maybe it's better to have one more)
Any approx cost idea from foundation to roof finish? one of guy told me it'll be in between 200~300 but considering the simplicity of work, I think it's a bit pricey.
Was this post helpful to you?   yes     no Report prohibited or spam
Simple addition
Amount: $0.00
Posted by: Waxy in Readington, NJ.Posted: August 21st, 2011 03:08PM
Sq Ft of Addition: 400Which Floor:
Number of Rooms: 1
I have a 20 by 30 deck that I would like to convert into a family room. No closets or anything. All windows and hardwood floors. What could I expect to pay for this.
Was this post helpful to you?   yes     no Report prohibited or spam

Page 3 of 3   -   << Previous   1   2   3   


Comment On Your Experience With a Home Addition
Subject:  *
Amount Spent:  *
Sq Ft of Addition: Which Floor: 
Number of Rooms:   
Purchased:  Year: 
City:  * State:  *
Information about you:
Email:  * Email addresses are not displayed.
Name:  This is the name we'll display with your post.
me on this computer
*=required field.

External Resources:
More Home and Garden Topics
Check Out All Costs for Home and Garden How Much Does a Kitchen Remodeling Cost? How Much Does a Propane Tank Cost? How Much Does a Plumber Cost?

Search Thousands of Topics on


Today's Featured Cost Articles

About CostHelper
CostHelper is based in Silicon Valley and provides consumers with unbiased price information about thousands of goods and services. Our writers are experienced journalists who adhere to our strict editorial ethics policy.

CostHelper Community
Angiogram of heart
Paid: 55150.00
Had this procedure done to check heart due to abnormal stress test. Did not need any stents or any other procedure as everything was negative... [more]
-Pamela Garrett
Angiogram Cost
HELP: asbestos in furance - many questions
Paid: 0.00
I am renting out my home in Grand Rapids, MI and have received a notice from the city that the home must be inspected... [more]
Asbestos Removal Cost
Paid: 45.00
The clamp was annoying so it took away concentration of the tiny sting of the needle. I had just turned 15 at the the time and I've had it for almost a year and it has healed fast and never given me any trouble... [more]
Body Piercings Cost
Paid: 3009.00
Single family home... [more]
Ductwork Cost
2 half shafts replaced
Paid: 140.00
Bought the axles myself on ebay for 40 each, then had a mobile mechanic come to my house to do the work. It is not a hard job, but has a couple tricky parts for a subaru. Easier for a honda or toyota... [more]
-Subbie Giy
Replacing a CV Boot Cost
Even with insurance looking at going broke
Paid: 55000.00
Recently on a camping vacation my 11 year old became very sick. Took him to the closest hospital. Found out he is type 1 diabetic. Was very sick and had to be flown from Rock Springs WY, to Salt Lake City, UT. 185 mile on the ground... [more]
-Broke and confused.
Air Ambulance Cost