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How Much Does It Cost to Build a Guest House? [2025 Data]
Normal Range: $62,000 - $225,000
The cost to build a guest house ranges from $62,000 to $225,000 depending on its size. Most spend an average of $85,000.
How we get this data
Photo: gzorgz / Adobe Stock
Photo: gzorgz / Adobe Stock
Cost Insights
One of the most costly additions to a home, a guest house often costs between $62,000 to $225,000, depending on its size and your location.
In most cases, you’ll pay between $110 and $250 per square foot to build a guest house.
Most general contractors charge between 15% and 25% of your total guest house cost, while electricians have hourly rates between $70 and $200, and roofers charge $25 and $75 per worker per hour.
Adding a guest house is one of the most expensive additions you can make to your home, averaging between $62,000 to $225,000 depending on its size and other factors. Most homeowners spend an average of $85,000 on building a guest house.
It’s important to consider the many benefits of this home addition. A guest house provides a comfortable space for visitors or long-term guests and boosts your property value. Learn all the costs of this valuable home addition project—and where you can save the most money.
Size of Guest House
The size of your guest house will be the largest factor determining its price, with a cost of around $110 to $250 per square foot. Here’s a look at the average cost ranges for guest houses based on their size.
| Size in Square Feet | Average Cost for New Build | Average Cost for Prefab |
|---|---|---|
| 300 | $45,000–$95,000 | $27,000–$53,000 |
| 400 | $55,000–$110,000 | $31,000–$59,000 |
| 550 | $80,000–$140,000 | $40,000–$88,000 |
| 800 | $115,000–$210,000 | $65,000–$110,000 |
| 1,200 | $170,000–$330,000 | $89,000–$160,000 |
| 1,500 | $210,000–$380,000 | $102,000–$220,000 |
General Contractor Costs
Hiring a general contractor for your guest house addition is key to a successful project. There are simply too many moving parts to keep track of unless you hire an experienced project manager. For a job this large it’s rare that you’ll be charged an hourly rate, so expect a general contractor to charge between 15% and 25% of the total project cost.
Electrician Costs
You’ll need to pay for the cost of an electrician to handle all the new electrical work in your guest house. Expect to pay hourly rates between $70 and $200 per hour depending on the complexity of the work. For a guest house, your electrician will need to splice power from a main source and wire the entire house, which can cost around $8,000.
Roofer Costs
A new roof costs an average of around $8,000 when building one for a guest house. On average, expect to spend between $4 and $11 per square foot depending on the material you choose. Roofer hourly rates fall between $25 and $75 per worker per hour. However, it’s rare to get charged hourly for a full roofing job.
Guest House Cost by Location
How much you pay for a guest house will also depend on where you live. In most cases, prices are the lowest if you live near a city center because materials are accessible and contractor competition is high. Here’s a look at average prices throughout the U.S.
| State | Average Cost for 600 square foot guest house |
|---|---|
| California | $110,000–$200,000 |
| New York | $125,000–$220,000 |
| Washington | $103,000–$185,000 |
| Tennessee | $80,000–$150,000 |
| Florida | $95,000–$175,000 |
| Texas | $90,000–$165,000 |
| Alaska | $125,000–$240,000 |
| Hawaii | $115,000–$230,000 |
| Michigan | $70,000–$120,000 |
| Wyoming | $90,000–$135,000 |
| Colorado | $120,000–$210,000 |
Additional Cost Factors
Photo: gzorgz / Adobe Stock
Demolition and Prep
You’ll need to clear an area for your guest house. Demolition crews charge $30 to $70 per hour per worker and often a disposal fee on top of that based on weight and material type. Prep work often involves leveling land, surveying, and pouring a foundation.
Permits
A guest house addition will always require a permit. If you aren’t familiar with the process, your general contractor will know the ins and outs. The cost of a permit runs between $600 and $3,000 for a guest house.
Taxes
You’ll pay more in property taxes based on the square footage of your guest house. For many homeowners, annual property taxes increase by 15% to 25%.
Insurance
A guest house will also increase your insurance fees. However, you will have more of a say when discussing your insurance premiums, especially if you bundle home and auto. Discuss your guest house plans with your insurance agent to learn how much it’ll cost.
Financing
You need money to build, and many homeowners opt for a traditional loan through a bank. The true cost of financing a home addition will come down to your available cash, income, credit score, and equity in your primary house. Make sure to shop around, as your primary bank may not offer the best rate.
Luxury Additions
While a new build is exciting on its own, you may consider adding some accessories or upgrading some furnishings. Just be aware that these choices will probably not yield the same return as the structure itself. For this reason, homeowners considering luxury additions should do so for livability purposes, not investment-based reasons.
| Accessory | Average Cost |
|---|---|
| High-end appliances | $6,000–$13,000 |
| Heated floors | $5,000–$16,000 |
| Granite countertops | $2,500–$9,000 |
| Sauna | $1,900–$5,000 |
| Wrap-around deck | $18,000–$36,000 |
| Security system | $2,000–$7,000 |
| Custom lighting | $1,500–$8,500 |
| Luxury bathroom finishes | $2,500–$8,000 |
| Solar panels | $12,000–$25,000 |
| Custom cabinetry | $5,000–$45,000 |
Plumbing
A guest house will require its own plumbing system. Plumbers charge hourly rates between $50 and $200 per hour. For a large project like a guest house, expect to pay more than $10,000 for a smaller job, or $20,000 and up for larger guesthouses.
Architect Design
An architect is a required professional when building a guest house. They may take a percentage of the project cost—around 15%—or they may charge hourly. You’ll want one of their senior architects, so expect to pay senior architect rates. These fluctuate, but a good range is $180 to $300 per hour.
Painter Costs
Photo: skynesher / E+ / Getty Images
This is one aspect of the project you may opt to do yourself. If you decide not to sink hours into painting, painting crews will charge $3 per square foot on average. On the other hand, if you want to pay hourly, that would be around $45 per hour per worker—more if they’re specialized.
Foundation Work
A foundation is a requirement for a new guest house. If you choose not to pour your own, you need to hire a foundation pro. The average guest house foundation costs between $3,500 and $16,000 depending on size. While you can do this job yourself, it’s not worth the undertaking and possible breach of zoning and permit use. A pro will charge 40% or more of the total cost as this is a labor-intensive job.
Carpentry
Your general contractor may bring on a carpenter to do some of the work. Carpenters charge between $35 and $200 per hour, which often comes to around $6,000 to $12,000 for a guest house.
Home Inspections
After your guest home is finished, you’ll need to pay to have it professionally inspected. Home inspections cost an average of $400 and they ensure that your guest house is up to code.
HVAC Installation
Installing an HVAC system costs between $5,000 and $12,500. HVAC pros may charge per hour for smaller jobs but for a guest house addition, expect to receive a flat quote.
Why You Should Hire a Home Addition Contractor
If you hire a local home addition contractor to build your guest house, 10% to 20% of your total project cost will go toward labor. While that's a significant amount for a project of this scale, it's worth the cost to ensure your guest house is built to code and gives you a return on your investment. Contractors can handle a range of complex tasks involved, including electrical, plumbing, and HVAC installation.
Here’s why it’s ideal to hire a home addition contractor
Building a guest house is often as complex as building a full-sized home, just on a smaller scale. Hiring a home addition contractor offers the following advantages:
Pros ensure structures comply with local building codes, zoning laws, and regulations.
They can advise you on types of additions that meet your needs, property, and budget.
Pros can handle or subcontract all of the required electrical, plumbing, and HVAC tasks.
A contractor-built guest house will be free of leaks, foundation issues, faulty electrical, and other hazards.
DIY mistakes can result in a structure that actually detracts from a property's value.
Tips to Reduce Cost While Building a Guest House
Because building a guest house has so many aspects, there are also plenty of places to cut down on costs, including:
DIY easy finishing touches, like painting and flooring.
Use cost-effective, recycled materials.
Use energy-efficient systems to reduce long-term costs.
Find the best possible financing terms.
Hire local contractors in their least busy season, then negotiate their rate.
Get bulk discounts.
Use percentage-based coupons for larger items.
Does Adding a Guest House Increase Home Value?
Adding a guest house increases your home’s value by 20% to 40%, on average. Most guest houses recoup 50% to 75% of their cost, which is a high return on investment (ROI) for a home addition project.
Another way a guest house boosts home value is that the property may be able to generate rental income. This is especially attractive to buyers who are looking for properties that can offset their mortgage costs. Banks may also be willing to give those same buyers better terms on their loans if they can prove rental income would help lower the mortgage risk.
Finally, adding a guest house gives a property a luxurious flair and significantly increases enjoyment of the space—especially if a large family lives under a single roof.
Pro Tip
There is some demand in the market for ADU's, specifically in-law suites. Most of this is driven by new homebuyers looking for ways to help pay their mortgage by renting space without having to qualify for an additional loan to purchase a separate investment property. This has increased as mortgage rates have continued to increase and homebuyers look for ways to save.
Next Steps: Finalize Your Project With a Pro
Be prepared to discuss whether a custom-built, modular, or prefab home best fits your budget.
Know your goals for the project, including your intended use for the structure and whether you see it as a potential rental property.
Have an idea of your property size and where you'd like to build the new guest house.
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