Table of Contents
What dimensions do I need my concrete slab?
Generally, for most sheds and garages, I recommend your concrete slab be 1 foot
wider and longer than the dimensions of your building. For example, if your building
is 24’ wide by 35’ long, your concrete slab should also be 25′ wide by 36′ long.
Footings- For standard buildings (12 wide – 30 wide ), you should have a minimum of a 12-inch by 12-inch footing to accommodate concrete anchors, the remainder of the slab can be 4 inches. I also suggest checking in with your city or township, local code requirements may differ.
Concrete Apron– If your building contains an overhead or roll-up door, I recommend you have a slope going away from your door openings.
The reason for this is to prevent water from seeping underneath your doors. The slope should consist of a minimum 3/4 inch drop & at least 4 inches further from the outside of the building.
Ask your concrete contractor for further recommendations.
Benefits of a concrete slab
A. There are numerous advantages to pouring a concrete slab as the foundation for your steel building. Top benefits include redirecting rainwater away from the building and reducing condensation.
I recommend an edge flush detail on your concrete slab to redirect rainwater away from the walls and base rail of your building. This detail will direct the flow of water away from the concrete slab and effectively eliminate water seepage beneath your base rails.
As you may know, ground emits an amount of moisture which can lead to a higher amount of condensation on the inside of your steel building. When poured, the slab acts as a barrier against ground moisture and helps reduce
the amount of condensation on the interior of the building.
It is a good idea to put down plastic sheeting before you place your shed if you are not putting down a concrete slab.
How long should I let my slab cure for?
Concrete should be allowed to cure from anywhere between 3 and 9 days, depending on the temperature and moisture levels, according to the National Ready Mixed Concrete Association. Lower temperatures and higher moisture levels result in a longer curing time. Waiting longer will greatly reduce the risk of concrete cracking. Concrete continues to cure up to 28 days after it is poured.
Should I pour my slab before or after I get my building?
This depends upon your project. For most build-on-site projects, it is easiest to pour before you build. Anchor your building to your slab with concrete wedge anchors.
For delivered buildings, you always want your slab put down before your shed arrives.
However, your budget may not allow for a slab. Many customers have poured the slab after installation of a built on-site garage, pole barn, or large shed.. Consult with a local building inspector and a local concrete contractor about pouring after installation.
How can I tell if my ground is level?
Prior to the delivery of a shed, you are responsible for assuring that your site is properly prepared and ready for installation. For all installations, the site must be completely level.
On unlevel ground, this may mean preparing a gravel or cement pad, or can be down by leveling your shed with blocks. Most shed companies will level your building with block if you do not have a level site.
If the shed is not level, doors and windows may stick.
Proper site preparation is always important with any building.
