Absolute Steel barndominiums and kit homes are designed to be anchored to a concrete footing or slab. While technically, our buildings can be installed on bare earth, because someone will be living in the barndominium or kit home local building codes will apply. Those building codes will require a concrete footing or slab.
SPECIAL NOTE FOR COLD WEATHER AREAS: The concrete applications described below do not account for frost line requirements. If you live in an area that has very cold winters and a frost line, your concrete footings will need to be deeper than what is illustrated here. Your local building authorities can provide information on frost line requirements in your area.
Concrete Slab Mounting
NOTE: ALWAYS check with your local building department for concrete requirements. We can supply engineered plans if you need. The information below is for general reference only and may not relate to your specific location.
Slab Sizing
Your slab is to be the same width as your building, and 2″ longer. For example, if you have purchased a 20′ wide by 40′ long building, your slab should be 20′ wide by 40′ 2″ long.
Slab Thickness
Your floor should be a minimum of 4″ thick. The concrete’s strength should be a minimum of 2500 psi, with fiber mesh reinforcement added at the batch plant OR #3 rebar on 24” centers.
If you are planning to park large, heavy vehicles inside (such as trucks or larger RVs), you should consider making the slab 6″ thick, and using 4000-psi concrete. You may not need this for a kit home, but often times a barndominium may be used to store vehicles and heavy equipment.
Be sure to saw-cut expansion joints in the slab, within an appropriate time after the pour, or troweled-in expansion joints done during the concrete finishing steps.
For the sake of estimation, we can tell you that in our local area (Phoenix, AZ), the cost for a 4″ slab runs about $4.50 per square foot. Prices in your area may be different.
Footing Requirements
At the same time as your slab is poured, you will also need to pour perimeter footings, as illustrated below. This is called a monolithic pour or monolithic slab.
Perimeter footings should be 12″ wide, and 12″ deep. (Deeper in the event you are contending with a frost line) You can include the 4″ slab thickness in the 12″ total depth; in other words, the footing would extend 8″ below the slab. As shown in the detail drawings, your footings will also need continuous runs of #4 rebar along the top and bottom.
In our local area, footings of this type would cost approximately $16.50 per lineal (running) foot.
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FAQs
The concrete's strength should be a minimum of 2500 psi, with fiber mesh reinforcement added at the batch plant OR #3 rebar on 24” centers. If you are planning to park large, heavy vehicles inside (such as trucks or larger RVs), you should consider making the slab 6″ thick, and using 4000-psi concrete.
How thick does a concrete slab need to be for a barndominium? ›
For barndominiums up to 1,500 sq. ft., most recommendations fall between a 4” and 6″ thick slab. This accommodates moderate traffic and furnishings adequately without excessive concrete use. The steel perimeter beams of barndominium kits require less internal slab support than wood framing.
What kind of foundation does a barndominium need? ›
Properly executed, an embedded perimeter beam concrete slab foundation formulated from high strength 5,000 PSI concrete mix designs provides ideal structural support for the tremendous clear spans and dynamic live loads generated over generations of family life within your barndo.
What do I wish I knew before building a barndominium? ›
Here are the most important things to know about building a barndominium.
- Obtain a permit for your project. Photo by Bridger Steel, Inc. ...
- Test the paint. Photo by Justin Doyle Homes. ...
- Prepare for surprise costs. ...
- Plan for electrical work. ...
- Choose your windows and doors wisely. ...
- Add insulation—it's important.
In most cases, a house should have a minimum footing of 12 inches wide by 12 inches deep, with foundations that are 8 to 10 inches thick. This should be enough to support house weight and resist lateral soil and water pressure.
What is the best slab for a barndominium? ›
Slab Thickness
The concrete's strength should be a minimum of 2500 psi, with fiber mesh reinforcement added at the batch plant OR #3 rebar on 24” centers. If you are planning to park large, heavy vehicles inside (such as trucks or larger RVs), you should consider making the slab 6″ thick, and using 4000-psi concrete.
How much weight can a 6 inch concrete slab hold? ›
How Much Weight Can a Concrete Driveway Hold? Typically, concrete driveways that are 4″ thick can withstand loads of regular vehicles, which is approximately 8,000 pounds. A 6″ thick concrete driveway can withstand heavy-duty trucks that can around weigh about 70,000 pounds.
What is the most expensive part of building a barndominium? ›
Steel framing, popular in barndominium construction for its durability and resistance to pests, can be more expensive than traditional wood framing. Framing costs can range from $20 to $50 per square foot, making it one of the most significant portions of the construction budget.
Do you need a vapor barrier on a barndominium? ›
As many barndominiums are constructed from metal, a vapor barrier tape will help prevent potentially damaging condensation from entering the structure. Reducing the energy costs to heat the home. Many barndominiums often have vaulted or cathedral ceilings, meaning the ceilings are not parallel to the floor.
Can any floor plan be a barndominium? ›
Whether an existing floor plan or a custom design – virtually anything you can imagine, can be converted to a post frame barndominium kit, provided it is possible to do structurally at all!
If you're considering building or buying a barndominium, consider this list of downsides before you sign your name on a dotted line:
- Location Limitations. ...
- Financing. ...
- Corrosion. ...
- Noise. ...
- UV Exposure. ...
- Wiring Challenges. ...
- Reselling.
Banks require appraisals to determine the property's value, which in turn, informs their lending decisions. Because barndominiums are relatively unique and fewer in number compared to traditional homes, finding comparable sales (comps) necessary for accurate valuation is difficult.
Do barndominiums have mold issues? ›
Due to the nonporous nature of steel buildings, barndominium owners often note increased condensation around the interior of their windows. This condensation can also penetrate drywall. If that happens, you will have a bigger problem on your hands: mold.
What is the rule of thumb for concrete footings? ›
Footing width can vary according to the structure, site, and conditions. Under code, generally, one-story buildings with footings on undisturbed soil with LBVs between 1,500 and 4,000 should have a minimum width of 12 inches. Two-story buildings require a minimum of 15-inch wide footings for 1,500 LBV soil.
What is the best concrete strength for foundations? ›
GRADE: C25 CONCRETE
A multi-purpose concrete that is used on a wide range of commercial and domestic construction sites. C25 is often used as a foundation concrete mix when pouring foundations (footings). It is also the ideal concrete for domestic slab foundations for house and bungalow floors.
How deep and wide do footings need to be? ›
A minimum of 12”inches deep for all footings and the width will be determined by the amount of stories, 12” inches for a single story, 15” inches for a two story and 23” inches for a three story. This is based on a soil bearing capacity of 1500(psf).
Do I need a 4 or 6 inch concrete slab for a garage? ›
Light Burdens: This type of garage floor requires at least 4 inches of concrete and is suitable for one or two light cars or trucks. Medium Burdens: Average-sized vehicles and medium to large trucks require a garage floor that is 6 inches thick.
How much weight will a 4 inch slab hold? ›
Generally, a 4-inch surface can hold up to 4,000 pounds per square foot when adequately reinforced. Unreinforced, it can only hold 40 pounds per square foot. Steel bars or wire mesh can be placed in the concrete before it is poured to reinforce the pad.
Is 3 inches thick enough for concrete slab? ›
Typically, 4 to 6 inches is plenty, but you want a concrete base that is durable and strong enough to withstand the weight of your home and everything in it.
Is a 2 inch concrete slab enough? ›
While it may be suitable for light-duty applications like footpaths or patios, a driveway requires a thicker concrete slab to withstand the weight and impact of vehicles. A 2-inch concrete driveway may be prone to cracking, sinking, and structural issues due to insufficient strength and load-bearing capacity.
