The cost to add a room to a house is about $22,000 to $83,000 for most U.S. homeowners, or about $80 to $210 per square foot, according to HomeAdvisor (updated June 17, 2026). Prices run higher in big metro areas. Block Renovation (July 2026) puts permitted additions at $200 to $600 per square foot in many mid- and high-cost metros. In the Portland, OR market, the 2024 Cost vs Value report lists a midrange bathroom addition at $65,376 and a midrange primary suite addition at $171,795.
This guide gives you price tables by room type and size, whether you are pricing the cost to build an addition onto a house or a single new bedroom. Every number names its source and date. Where we do the math ourselves, we say so.
A typical room addition costs $22,000 to $83,000 nationally (HomeAdvisor, June 2026), and a bedroom with a bathroom averages $103,300 (HomeAdvisor, June 2026).
Bathrooms cost more per square foot than bedrooms because of plumbing, waterproofing and tile.
A bump-out is usually the lowest-cost way to gain space. A room above a garage costs more because the garage may need new supports.
Sources disagree by two to three times. Ask every contractor for an itemized quote so you can compare.
Simple shapes and plumbing near existing walls save the most money.
Three well-known cost sites give three different national answers:
HomeAdvisor (updated June 17, 2026): average $50,994, typical range $21,895 to $83,355.
Fixr (updated February 3, 2025): average $65,000, typical range $30,000 to $100,000.
Block Renovation (July 7, 2026): $200 to $600 per square foot in many mid- and high-cost metros, which puts a simple 600 square foot family room at $120,000 to $240,000.
Why the gap? The sources measure different things. National averages blend small, simple rooms with large, finished ones. Block also notes that design, structural engineering and permit costs frequently sit outside the headline number, and it lists HVAC and utility upgrades as separate line items.
Local labor, site conditions and permits all vary, so ask for a written, itemized quote. Our home additions and ADU services in Vancouver, WA page explains how we scope these projects.
Per-square-foot pricing is the fastest way to compare quotes. These are the ranges we found.
Here is the math for a 12 by 12 room, which is 144 square feet. At HomeAdvisor's $80 to $210 range, that is about $11,520 to $30,240. At Block's $150 to $350 range for a basic room, it is about $21,600 to $50,400.
This table shows the typical range for each type of room. All figures are national unless noted.
Angi (September 24, 2026) lists a national average of $50,000 for a bedroom addition and a typical range of $20,000 to $130,000. Labor makes up 40% to 60% of the total.
Size matters. Angi shows $10,000 to $75,000 for 100 to 150 square feet, $15,000 to $125,000 for 150 to 250 square feet, and $25,000 to $200,000 for 250 square feet or more. The wide spread comes from finishes and site work.
A bathroom costs more per square foot than a bedroom because it needs plumbing, waterproofing and tile. Fixr (January 22, 2026) says a new bathroom addition runs $400 to $550 per square foot. Converting existing space costs $200 to $250 per square foot.
Plumbing alone for a full bath runs $2,000 to $10,000, according to Block Renovation (September 26, 2025). The cost climbs if the new pipes must travel far. If you only want to update an existing bathroom, see our bathroom remodel cost guide for Vancouver, WA.
A bump-out pushes one wall out a few feet. Angi (May 3, 2026) says bump-outs typically extend 2 to 15 feet from an existing room. A "cantilever" bump-out, which needs no new foundation, is typically limited to 24 inches.
Fixr (February 3, 2025) says a bump-out can save about 15% compared with a conventional addition. Use it for a bigger kitchen, a primary bath or a bedroom closet.
Fixr (February 3, 2025) lists a sunroom addition at $35,000 to $70,000. That is a national range from an older page than most figures in this guide, so ask for a current quote.
This section covers a room above a garage you already own. We did not find a sourced figure for the cost to add a garage to a house, so we do not give one.
Block Renovation (December 22, 2025) lists $45,000 to $60,000 for a basic bonus room above a garage. A full primary suite with a bathroom and walk-in closet runs $80,000 to $200,000. The per-square-foot range is $150 to $450.
The big extra cost is structure. Block says many garages need $5,000 to $40,000 or more in new supports or foundations.
Moneyzine (December 16, 2024) estimates a 450 square foot suite over a garage at about $200,000, based on roughly $450 per square foot. Treat that as a single high-end example, not an average.
It depends on whether the existing garage can carry a new floor. Block Renovation (December 22, 2025) says the garage walls and footings must support the new space, so the structure needs a check before design starts. Clark County says most additions need a permit and follow-up inspections.
HomeAdvisor (June 20, 2026) lists an average of $103,300 for a bedroom and bath addition. The normal range is $37,500 to $117,000. For a 400 square foot suite, HomeAdvisor shows $32,000 to $88,000. For 600 square feet, it shows $48,000 to $132,000.
Block Renovation (July 7, 2026) is much higher. It lists a 600 square foot primary suite at $150,000 to $300,000 or more. The Portland figure from the 2024 Cost vs Value report, $171,795 for a midrange primary suite addition, falls inside Block's range, although the two sources come from different years.
Use this table to find your range by square feet. The first column comes from Fixr (February 3, 2025). The second column is our arithmetic using Block's $150 to $350 per square foot for a basic room (July 7, 2026).
If a quote falls far outside both columns, ask why. A custom roofline, a tight lot or a complex foundation can explain it.
You have several common ways to gain space. Each has a different price and a different best use.
Block Renovation (July 7, 2026) says building out is often the simpler path when the lot allows it, but it is not automatically cheaper because a ground-floor addition still needs a new foundation, while building up adds structural and roof work. If you own a split-level, read our split-level home remodel ideas and costs guide, which covers options for those layouts. For a separate unit, see ADU building requirements and costs in the Portland area.
Labor is the largest share in the sources we reviewed. Angi (September 24, 2026) says labor makes up 40% to 60% of a bedroom addition, and Block Renovation (December 22, 2025) gives the same range for a garage suite. Structure can add a large line item too, since Block says many garages need $5,000 to $40,000 or more in new supports or foundations. By room type, bathrooms cost the most per square foot, at $250 to $600 or more according to Block (July 7, 2026).
The ground under a new room sets part of your price. Block lists excavation, drainage, soil and access as cost drivers. Angi (May 3, 2026) puts foundation work at $5 to $37 per square foot.
A simple roof is cheaper than a complex one. Matching siding, windows and trim on an older home also adds cost, according to Block (July 7, 2026).
Fixr (February 3, 2025) lists framing at $15 to $25 per square foot, electrical at $3 to $10 and HVAC at $2 to $6. Windows run $250 to $1,500 each and doors run $350 to $2,200. Block adds that HVAC capacity upgrades often cost $3,000 to $15,000 or more, and utility upgrades often cost $2,000 to $15,000 or more.
Block (July 7, 2026) lists design at $2,000 to $20,000 or more and structural engineering at $1,000 to $5,000 or more. Fixr estimates design fees at 10% to 17% of the final cost. Labor is often 40% to 60% of the budget, according to Block (December 22, 2025).
Permits are a small slice of the total. HomeAdvisor (June 17, 2026) lists $200 to $3,000, depending on location and scope. Clark County says most additions need a permit and follow-up inspections, and the City of Vancouver fee schedule (effective January 1, 2026) sets building fees by project value. Which office handles your permit depends on whether your home is inside a city or in unincorporated Clark County.
We could not find a published price study for Vancouver, WA alone. Remodeling magazine's Cost vs Value report does publish nearby numbers, shown below. These are the report's midrange project definitions, not quotes.
Source: Cost vs Value Report from Remodeling magazine (Zonda), as published by the Journal of Light Construction: Portland, OR 2024, Seattle, WA 2025 and Pacific region 2025. The Pacific region 2024 column comes from the same report's 2024 Pacific page. The 2025 report did not list Portland, so we use the 2024 Portland report. Reports from different years are not directly comparable, so read the two 2024 columns against each other and the two 2025 columns against each other.
We found no 2026 Cost vs Value edition as of October 15, 2026.
Four local factors can move your price:
Lead-safe rules for older homes. The EPA's Renovation, Repair and Painting rule covers homes built before 1978. Firms paid to disturb painted surfaces must be certified. In Washington, the state Department of Commerce runs the certification program. If your Hazel Dell, Cascade Park or Felida home is older than 1978, expect lead-safe setup in the quote.
Energy code. The Washington State Building Code Council lists the 2021 Washington State Energy Code, Residential, effective March 15, 2024, as the current edition. A 2024 edition has been proposed, with a proposed effective date of May 3, 2027, so ask your contractor which edition applies to your permit date.
Wet weather. Western Washington's rainy season makes drainage, site access and scheduling worth pricing early.
Oregon projects. Oregon also runs its own authorized lead program. Ask a Portland contractor to confirm which rules apply.
We build additions in Vancouver, Camas, Ridgefield, Felida, Salmon Creek, Hazel Dell, Cascade Park, Battle Ground and Portland.
Block Renovation (July 7, 2026) and Fixr give these cost-saving tips, and we agree with all of them:
Keep the footprint a simple rectangle. Corners and jogs add framing and roof work.
Simplify the roofline. A single gable or shed roof costs less than a complex tie-in.
Put new plumbing near existing wet walls. Long pipe runs add cost, as Block's bathroom guide notes.
Decide early how the room will be heated and cooled. Late HVAC changes are expensive.
Avoid late window and door changes. They can change framing and ordering.
Price the shell first. Choose finishes after you know the structure cost.
Consider a bump-out. Fixr says it can save about 15% over a conventional addition.
Keep a 10% to 20% contingency. Block recommends this for surprises in older homes.
An addition adds value, but it rarely returns every dollar. Remodeling magazine's 2025 Cost vs Value report (Pacific region) shows a midrange bathroom addition recouping 57.5% of its cost and a midrange primary suite addition recouping 32.2%. The 2024 Portland figures were 43.5% and 49.1%, and the 2024 Pacific region figures were 47.4% and 54.4%, so recoup rates changed a lot from year to year. We found no 2026 edition of the report as of October 15, 2026.
Block Renovation (July 7, 2026) lists a 50% to 70% return for a bedroom addition. Think of an addition as buying space you will use, with resale value as a bonus. If you only need a better layout, a full home remodel may be a better fit than building new square footage.
Salcans Remodeling is a general contractor in Vancouver, WA serving Clark County and Portland. Your price depends on your lot, your foundation and your finishes.
Ready for real numbers? Request an estimate and tell us about your lot, your home and your goals.
About the author: Salcans Remodeling Team. 8 years in business, 30+ years of work experience. 80+ client reviews. Washington L&I-registered contractor SALCAL*825LE, which you can verify on the L&I website.
Most U.S. homeowners pay about $22,000 to $83,000, with an average near $51,000, according to HomeAdvisor (June 17, 2026). Prices run higher where labor costs more. Block Renovation (July 7, 2026) reports $200 to $600 per square foot for permitted additions in many mid- and high-cost metros.
HomeAdvisor (June 17, 2026) lists about $80 to $210 per square foot nationally. Fixr (February 3, 2025) lists $100 to $300 for a finished addition. Block Renovation (July 7, 2026) lists $150 to $350 for a basic room and $250 to $600 or more for a bathroom.
A 12 by 12 bedroom is 144 square feet. At HomeAdvisor's about $80 to $210 per square foot (June 17, 2026), that is about $11,520 to $30,240. At Block Renovation's $150 to $350 per square foot for a basic room (July 7, 2026), it is about $21,600 to $50,400. Angi (September 24, 2026) lists $10,000 to $75,000 for a bedroom addition of 100 to 150 square feet.
A 20 by 20 room is 400 square feet. At HomeAdvisor's about $80 to $210 per square foot (June 17, 2026), that is about $32,000 to $84,000. At Block Renovation's $150 to $350 per square foot for a basic room (July 7, 2026), it is about $60,000 to $140,000. Fixr (February 3, 2025) shows $40,000 to $120,000 for 400 square feet at $100 to $300 per square foot.
Fixr (February 3, 2025) says a bump-out can save about 15% compared with a conventional addition. HomeAdvisor (June 17, 2026) lists $4,000 to $30,000 for a bump-out, and Angi (May 3, 2026) puts the average at $27,000. Fixr (January 22, 2026) also prices converting existing space into a bathroom at $200 to $250 per square foot, against $400 to $550 for a new bathroom addition.
Block Renovation (July 7, 2026) says building out is often the simpler path when the lot allows it, but it is not automatically cheaper because a ground-floor addition still needs a new foundation, while building up adds structural and roof work. Its second-story range is $200 to $500 or more per square foot, compared with $150 to $350 for a basic room. Your lot, local zoning and existing foundation decide the answer.
Block Renovation (December 22, 2025) lists $45,000 to $60,000 for a basic bonus room above a garage and $80,000 to $200,000 for a full suite with a bathroom. It also notes that many garages need $5,000 to $40,000 or more in new supports or foundations. The per-square-foot range is $150 to $450.
Block Renovation (July 7, 2026) lists a 50% to 70% return for a bedroom addition. In the Cost vs Value report, a midrange primary suite addition recouped 32.2% in the Pacific region in 2025, 54.4% in the Pacific region in 2024 and 49.1% in Portland in 2024. Recoup rates changed a lot from year to year, and we found no 2026 edition.
HomeAdvisor, "Cost to Build an Addition," updated June 17, 2026, and "Cost to Add a Bedroom and Bath," updated June 20, 2026.
Angi, "How Much Does a Bedroom Addition Cost?" updated September 24, 2026, and "Bump-Out Cost," updated May 3, 2026.
Fixr, "House Addition Costs," updated February 3, 2025, and "Bathroom Addition Cost," updated January 22, 2026.
Block Renovation, "The 2026 Home Addition Costs Guide," July 7, 2026; "Master Suite Additions Over Your Garage," December 22, 2025; "How Much Does a Bathroom Addition Cost?" September 26, 2025.
Moneyzine, "Second Story Addition Over Garage Cost," last updated December 16, 2024.
Remodeling magazine (Zonda), Cost vs Value Report, as published by the Journal of Light Construction: Portland 2024, Pacific region 2024, Seattle 2025 and Pacific region 2025. No 2026 edition found as of October 15, 2026.
City of Vancouver, Building Permit Fees, effective January 1, 2026. Clark County, Residential Projects page, accessed October 15, 2026.
U.S. EPA, Renovation, Repair and Painting Program, which lists Washington and Oregon as authorized states, accessed October 15, 2026.
Washington State Building Code Council, Energy Code page, accessed October 15, 2026.
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