Learn About Spiral Staircase Foundations
Before installing your spiral stair, or even choosing a place to install your spiral stair, one important factor to take under consideration to ensure the long-term stability of your stair is that of the foundation. While the foundation is not technically a spiral stair component, it is still very important to understand the ground directly underneath where your new staircase is going to go.
Indoor Foundations
If your spiral stair will be indoors then it’s highly unlikely that you’ll have to make any adjustments to your floor space before installing your spiral stair.
One location where you may consider making adjustments is if your stair will be on a concrete floor in the basement.
The concrete will be more than stable enough. But it may have some cracks or crumbling in it due to age and maybe even water flow through some storm doors and across the slope of the floor toward the sub pump. Especially if it’s an older house with an unfinished basement.
If this is the case then taking the time to fill these cracks with a quick concrete mix and trowel job should be sufficient. Let the concrete repairs cure then install as planned.
Outdoor Foundations
If you’re spiral stair is going to be outside then there are a lot more dynamics to consider. Will this stair be on a deck, patio, driveway, or just a concrete pad? Or is there any type of finished floor at all where you plan to install the stair? Each of these will have different factors to check before knowing the stair will be secured.
Locations
Different Foundation Types
Learn about each of these locations and how their foundations work
Deck
If you’re mounting a spiral stair directly to your deck then you’re likely safe. Especially if the deck is of newer construction. If you’ll be installing a heavier outdoor stair such as a galvanized steel stair instead of an aluminum stair, then it might be prudent to install extra support into your joist system beneath the floor boards just under where you’re putting the spiral stair.
Driveway
If your driveway is blacktop, concrete, or any other hard surface with a sufficient depth to it, then your surface is stable enough for installation. Just check how long the bolts for your base plate mount will be so you know you have a thick enough surface to work with. Just keep in mind the same principle as with the basement concrete floor.
Patio
The same principle applies to patios. If it’s made from pavers that haven’t been mortared together then you’ll need to first install a footer. You may need to teach yourself/lookup how the cut a circle into your current pavers so you don’t have to lay new ones down and so you don’t interrupt the flow/pattern of your pavers. Once you’re circle is cut, you have space to pour your footer.
Concrete Pad
A monolithic pour concrete pad is just like any other; make sure it’s in good shape prior installing a heavy spiral stair atop it. Repair cracks and crumbling. And make sure it’s of a sufficient thickness before bolting your stair base into it.
Slope
One issue that immediately makes for a precarious foundation is any kind of slope. Whether it’s how your land lays or if your concrete pad is sinking on one side. If you have a problem with the ground sinking where you’d like to pour a concrete pad then you need to do some direct filling prior to pouring a pad.
Footer
One of the simplest, non-invasive things to do in your yard to create a workable platform for your spiral stair is to install a concrete footer. This is essentially just a concrete tube that goes below your ground a little deeper than your local frost line. This is a common foundation for deck posts.
The Salter Experience
Experience unmatched quality & service
Proudly made in the USA, bringing premium spiral stairs straight to your door.
A consultative process
As part of our design process, you have access to our spiral stair experts through a FREE consultation to ensure we design the perfect stair solution for you.
Ships straight to you
All spiral staircases are packaged into a kit for the easiest and most cost-effective transport through the best local carriers, and delivered anywhere in North America.
Simple and easy installation
Spiral staircase kits can be built in under a day by two average homeowners and require no special tools. For added support, our team is here to help.
Peace of mind warranty
You can be confident in your purchase for years to come with our lifetime warranty on metal fabrication and 5-year warranty on all other materials.