Outbuildings cost $2,200 to $22,000, averaging $10,000 for a structure measuring 12 by 12 feet. You’ll pay $15 to $150 per square foot, depending mostly on materials and prefab or custom. Prefab metal kits are the least expensive at $10 to $30 per square foot. If you want custom brick construction, plan to spend $50 to $150 per square foot. Finished workshops run $30 to $200 per square foot.
Updated February 22, 2022
Written by HomeAdvisor.Outbuildings can be a great way to increase living space on your property without having to add onto your house. If you’re trying to stick to a budget, selecting one of the many prefab options may help you save money. You can also make the structure as comfortable as your home, although it costs more. Consider these projects to learn more about what you can expect to pay.
| Average | $10,000 |
| High | $22,000 |
| Low | $2,200 |
* Assumes a structure measuring 12’ x 12’
The cost to build an outbuilding ranges from $1,000 to $60,000, averaging $10,000 for most common sizes. Estimates depend on the size and the type of material.
| 8’ x 8’ | $1,000 - $9,600 |
| 10’ x 10’ | $1,500 - $15,000 |
| 12’ x 12’ | $2,200 - $22,000 |
| 10’ x 20’ | $3,000 - $30,000 |
| 20’ x 20’ | $6,000 - $60,000 |
Outbuildings cost $15 to $150 per square foot. You’re likely to spend the most on expensive materials like brick or additional finishing, such as HVAC or plumbing.
| Steel/Metal | $15 - $70 |
| Wood | $20 - $100 |
| Concrete | $15 - $50 |
| Stone or Brick | $50 - $150 |
Steel or metal outbuilding prices range from $15 to $70 per square foot. You’ll pay less to have a pro assemble a prefab kit, and more for them to build it from scratch. This style tends to be the most affordable unless you’re planning to line it with Kevlar to make it impact-resistant.
If you want a concrete outbuilding, you can expect to pay $15 to $50 per square foot. The material is the least expensive option, but it’s heavy. More labor leads to a higher price.
Stone or brick outbuildings cost $50 to $150 per square foot. These materials are the most expensive, at around $30 to $100 per square foot. You’ll probably need custom construction, which explains the higher price.
A building permit costs $500 to $2,300. Prices depend on your area and the size of the project.
Building a second structure onto your existing property usually requires building permits. Every city has specific rules you must follow, such as the outbuilding’s proximity to your house. Pros may or may not handle this for you, so it’s wise to ask. If you live in a community with a homeowners association, you’ll probably also need to get permission from them.
The price to build a workshop in the backyard ranges from $6,000 to $120,000, or $30 to $200 per square foot. The total depends on size, materials and finish.
| 10’ x 20’ | $6,000 - $40,000 |
| 20’ x 20’ | $12,000 - $80,000 |
| 20’ x 30’ | $18,000 - $120,000 |
Building a shop costs $30 to $200 per square foot. You’ll pay $30 to $50 per square foot for a metal prefab kit with minimal finishing. Custom options run $50 to $200 per square foot.
Finishing may add $10 to $100 per square foot to the total. If you want a completely finished wood shop or auto shop, you can expect to pay the cost to build a house, which is $100 to $200 per square foot. On top of construction or assembly, the project may require these services:
Cost to finish drywall: $1-$3 per square foot
Price to install new plumbing: $4.50 per square foot
Cost to install an HVAC system: $25-$60 per square foot
Price to build a floor: $10-$32 per square foot
Cost to install a window: $85-$1,400 per window
Price to install electrical wiring: $6-$8 per foot
Keep in mind that the more your outbuilding resembles the level of finishing in your house, the more expensive it is. If you’re trying to save money, a simple storage shed that you occasionally use for projects may only need battery-operated lighting and a cement floor.
Outbuilding prices range from $400 to $180,000. You’ll pay the least for an inexpensive treehouse or playhouse, and the most for a pool house.
| Barn | $10,000 - $100,000 |
| Shed | $200 - $30,000 |
| Outhouse | $1,500 - $5,000 |
| Garden Room | $10,000 - $70,000 |
| Greenhouse | $7,400 - $28,400 |
| Conservatory | $10,000 - $80,000 |
| Bomb Shelter | $37,000 - $65,500 |
| Storm Shelter | $2,600 - $10,000 |
| Treehouse | $400 - $15,000 |
| Playhouse | $500 - $15,000 |
| Pool House | $27,000 - $180,000 |
| Guest House | $45,000 - $100,000 |
Building a barn costs $10,000 to $100,000. The price to build a shed ranges from $200 to $30,000.
The cost to build an outhouse is $1,500 to $5,000. Options with a composting toilet system run the most.
Garden room prices range from $10,000 to $70,000, depending on the type. Modern styles run on the higher end.
The price to build a greenhouse is $7,400 to $28,400, or about $25 per square foot. Average sizes range from 500 to 1,000 square feet. A conservatory costs $10,000 to $80,000.
Building a storm shelter costs $2,600 to $10,000. By comparison, the price to build a bomb shelter is $37,000 to $65,500.
The cost to build a playhouse is $500 to $15,000. Prefab kits are $500 to $5,000. Building a treehouse costs $400 to $15,000. Custom or large designs run higher.
The price to build a pool house ranges from $27,000 to $180,000. Building a guest house costs $45,000 to $100,000.
Prefab outbuilding prices usually run $10 to $30 per square foot, not including labor. For most custom structures, you’ll pay at least $50 per square foot.
A good rule of thumb is that more customization leads to higher prices. A pre-fabricated building kit varies based on:
Size
Complexity
Quality of materials
Brand name
Kits that cost less may not have as many options. If you want a solid wood or brick outbuilding, you’ll need to find a custom builder.
The cost to build a small workshop measuring 100 square feet is $3,000 to $20,000, or $30 to $200 per square foot.
The cost to hire an architect to create workshop plans is $2,500 to $8,000. For a fully-finished structure, you’ll probably need one to ensure the building is sound.
Outbuildings may increase property value, but it depends on a few factors. A finished workshop or guest house might add up to $20,000. By comparison, sheds with no foundation usually don’t count on an appraisal.
You can build your own outbuilding using a prefab kit that costs $10 to $30 per square foot. Keep in mind that you’ll need at least two people who can carry up to 75 pounds. Hiring a pro usually takes less time.
If you’re planning to build a woodshop or workshop on a budget, try these cost-saving methods:
Buy a prefab kit made of steel.
Hire a pro to pour a concrete pad, but assemble the kit yourself.
Consider battery-operated tools and lighting instead of running wiring.
