Building, Garage

Prefab or Site Built Garage: Which Cost Less

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Adding a garage to your property adds value and makes the home more livable. Many people will consider prefab garages and site-built garages when weighing their options. There are many people, however, who wonder if it costs less to build a garage or buy a prefab garage.

Generally speaking, you will save money with a prefab garage over a site-built garage. If your goal is a basic garage design, then a prefab garage will cost less. However, you have more design freedom with a site-built garage. Building a garage on your property often requires additional work, time, and money.

Site-built GaragePrefab Garage
Lowest Cost$35/SF$15/SF
Average Cost$50/SF$38/SF
Highest Cost$75/SF$65/SF
The figures above are an average we collected from multiple websites and vendor websites.

Is it Cheaper to Build or Buy a Garage?

There are also some considerations of the type of foundation, additional add-on items, and the garage is attached or detached.

The first thing that we will look at is the foundation type. The foundation is one of the more costly items associated with building a garage.

If you are building a detached garage, you will need a foundation, but it is not what you need for an attached garage. In many cases, a gravel pad is all that is necessary.

If you would like to take things to the next level, you can add a poured concrete slab and put the detached garage directly on it. Doing so is often preferred but will add significantly to the cost.

All garages should be on a solid foundation. Propping the garage on a stack of bricks or concrete cinderblocks is a bad idea. You will end up regretting it in the future.

If the garage is attached to the home, you will typically need to have poured footers along with a concrete slab. Other costs are associated with attached garages, including the possibility of surveying, architectural drawings, and contractors.

What Type of Detached Garage Should You Choose?

If you chose a prefabricated detached garage, there are several options to consider. Each of these will have its own cost associated with it, as well as some benefits.

For a smaller, one-car garage, a very convenient option is to have the entire building prefabricated and delivered to your home. A fully prefabricated garage provides benefits, including significant savings and costs.

A benefit that is commonly overlooked for prefabricated garages is that they are constructed to withstand travel. Often, the building materials and construction are a little better for that very purpose.

You can also look into the possibility that a prefabricated garage is built inside of a warehouse. Many large manufacturers who make these garages on an ongoing basis will build them in that way. Having it built inside a warehouse means it is not exposed to the elements during construction.

One other option is to choose a modular garage. This is especially beneficial if you are choosing multi-car garages. It is also a good choice for those who want an apartment included above the garage.

There are some additional costs associated with modular garages that are not the same as prefabricated garages. Those costs include the need to assemble the garage on-site, costing money for equipment and contractors.

Many people find that modular garages are of benefit when they are attaching an apartment above the garage. Most of the work can be done before delivery, resulting in a finished product.

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How Much Does a Pre-Built Garage Cost?

Generally speaking, you will pay anywhere from $2000 – $100,000 or more for a prefabricated garage. That is a wide range, but the size and additions to the garage are going to differ. As a general rule of thumb, you will spend about $50 per square foot on a garage.

You can try some of the following options if you want to save money on a pre-built garage. These cost-saving options will not compromise quality.

  • Choose Steel: Most homeowners want a wood frame garage, perhaps with vinyl siding. But a steel garage is going to be the least expensive per square foot. You may spend up to five times as much for a wood frame garage.

Not everybody wants a steel garage on their property. If it works into your plans, it could save money on the project.

  • Add More Bays: The cost for the first bay could be twice as much in some cases as the additional cost for a second bay. As you continue to add more bays, the cost per bay is going to lower.

Adding bays is going to add to the cost of the garage. If you would rather have a two-car garage than a one-car garage, it is best to add it now instead of later.

  • Consider the Foundation: There is a significant price difference between having a gravel foundation or pad and a concrete pad under the garage. Both a gravel pad and a concrete slab will work for most garages. If you can live with gravel, you will save a lot of money.
  • DIY: The more you can be involved with the work, the more you will save money. As soon as you bring a contractor into the mix, you will spike the price considerably.
  • Delivery: Most prefab garage companies are going to charge a delivery fee. In most cases, it will be $10 per mile after it reaches a certain distance. If you can find a local company, you will likely save a lot of money on delivery fees.
  • Additions: Having a fully finished prefabricated garage may be out of your budget. It might be to your benefit to have the garage delivered and finish it at a later time.

Some of the additions that may be expensive include finishing the inside and insulating the garage. If you decided to have an apartment over the garage, finishing it later will save you a lot of money compared to having it delivered intact.

Building ComponentAverage Cost
Foundation (Concrete Slab)$4 to $8 /SF
Delivery$5.50 to $10 per mile
Electrical$1000 to $2500
Plumbing$600 to $1600 per fixture
HVAC$4000 to $10,000 per system
Permits$100 to $250 on average
Some of the data above were obtained from Does not include interior finishing.

Prefab Garage TypeEstimated Cost
1-Car (260/SF)$3900 to $16,900
2-Car (520/SF)$7,800 to $33,800
3-Car (780/SF)$11,700 to $50,700
4-Car (1040/SF)$15,600 to $67,600
Prefab with Second Floor Attic (520/SF + 260/SF Attic)$11,700 to $50,700
Costs are estimated based on information obtained online and from vendors. Does not include interior finishing.
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How Much Does a Site-Built Garage Cost?

The national average for a site-built garage is $27,000. That price is for one car attached garages. Adding additional items, such as finishing the interior or adding an apartment above the garage, can add tens of thousands of dollars to the project.

It is difficult to pin down exactly how much a site-built garage will cost. Typically, it is slightly more expensive than a prefabricated garage. That is due to additional costs, including the following.

  • Architectural Design: If you are building a garage from scratch on your property, you may have to have the proper plans in place. You may be required to have an architect involved to get the plans approved.
  • Surveyors: You might have to have your property surveyed if you are building a garage. A surveyor may be needed to layout the garage. They will also ensure that you are not encroaching on the neighbor or crossing a setback line.
  • Foundation: This is a considerable cost, as you may be choosing anything from a stone pad to a concrete slab.

These are only some of the many different options that will add to the price of the garage. If you are building the garage on-site, you can adjust your goals to match your budget.

What Factors Change the Cost of a Garage?

Multiple factors can change the cost of a garage and should be included in the plans. In some cases, those factors could add six figures to the overall cost.

  1. Foundation: The foundation will differ depending upon the garage type and the needs of the homeowner. Some options include gravel, concrete, and asphalt. There may be other options, depending on the area and what may be required by the local authorities.
  1. Contractors: If you can do most of the work on your own, you will save a lot of money. Hiring a contractor can get expensive, especially if you are adding a lot of additional features.
  1. Interior finishing: Not every homeowner will want to finish off the interior of the garage. It may be beneficial to at least insulate it, however, which can add significantly to the cost of the garage. Additional work can be considered as your budget allows.
  1. Living Areas: Some homeowners want an apartment above the garage. An apartment can add a significant amount of money to the overall cost. It may pay for itself over time if you rent it.

When you dig into the overall price of the garage, you will find that it is more expensive to build a garage for the first automobile. A two-car garage costs less than twice as much as a one-car garage, and adding a third bay is even less expensive.

Of course, you also need to factor in more than just the financial cost. The time and frustration of putting a garage on your property can be significant.

Building ComponentAverage Cost
Foundation (Concrete Slab)$4 to $8 /SF
Framing$10 to $25 /SF
Roofing$2 to $10 /SF
Siding$3 to $25 /SF
Overhead Garage Door$600 to $1500 each
Exterior Door$450 to $1000 each
Exterior Window$250 to $750 each
Garage Door Opener$250 to $650 each
Electrical$1000 to $2500
Plumbing$600 to $1600 per fixture
HVAC$4000 to $10,000 per system
Permits$100 to $250 on average
Some of the data above were obtained from Does not include interior finishing.

Site-built Garage TypeEstimated Cost
1-Car (260/SF)$9,100 to $19,500
2-Car (520/SF)$18,200 to $39,000
3-Car (780/SF)$27,300 to $58,500
4-Car (1040/SF)$36,400 to $78,000
2-Car with Second Floor Attic (520/SF + 260/SF Attic)$27,300 to $58,500
Costs are estimated based on information obtained online and from vendors. Does not include interior finishing.

What is the Cheapest Way to Build a Garage?

Many homeowners want to cut to the chase and build a garage for the lowest price possible. In doing so, they save money, and by following the proper guidelines, they can have a solid outbuilding at a reasonable price.

If you decide that you are not going for a prefab, which is the least expensive overall option, there are some ways to save money and still get a garage built.

  1. Pole Barn: One option is the possibility of erecting a pole barn-style garage. There is a lot less lumber involved in a pole barn garage.  There is a catch in that you may be losing something in the way of insulation.
  1. Garage Kit: Many hardware stores have garage kits available. Garage kits save you some money, but they also save you a lot of time and frustration. When you buy a kit, the store will deliver everything necessary to build a garage and even provide the plans.
  1. Stick Built: A third option is to build the garage from scratch in a stick-built fashion. This is only going to be an inexpensive option if you can do all of the work yourself.

Keep in mind that even the least expensive garage is going to require a foundation.

In addition, if you are trying to build a cheap attached garage, you have to go with the local code. Building an inferior garage and attaching it to the home will cause problems down the road.

Are Prefab Garages any Good?

There has often been an opinion that garages built on the property are of higher quality than a prefabricated garage. That is not true.

As long as you are using a quality company with a good reputation, a prefab garage can be just as strong, if not stronger, than a garage built on your property.

In part, this has to do with the fact that a prefab garage is often built with a stronger foundation so that it can survive the transport to your property. In addition, they may have been built indoors, so they weren’t exposed to the elements during construction.

It is also true that prefabricated garages are usually built for speed and convenience. They will last many years when you put them on your property, but if you want more control over everything that goes into the garage, building one yourself is a better option.

Before buying a prefabricated garage, check with the manufacturer and do your due diligence. Do they have a good reputation, and are they known for building a quality structure?

If you look into this in advance, there is no reason why you shouldn’t choose a prefabricated garage for your property.

Will You Need a Building Permit for Your Garage?

A building permit is required for garages in almost all areas. Check with your local city or town to see if they are needed when building a garage from scratch or delivering one. Once the permit is secured, you can start with the project.

If you try to build a garage without getting a permit, you may get in some hot water. The authorities might even want you to finish the job and bring it up to code, resulting in additional costs.

A building permit is also beneficial because it keeps you at the minimum standards for erecting a building on your property. There will also be inspections involved, so you can feel comfortable in the garage that you built.

Both a pre-built and a locally constructed garage can add much to the property. When you choose the one that fits your budget and your needs, you will have something on your property that will be available for many years to come.


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Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.