Concrete Slabs For Sheds - Everything You Need To Know

The thought of getting your new shed set up in your backyard is an exciting prospect, and there’s a number of questions you should answer before jumping in and getting to work. One of the most important things you need to consider is getting a solid concrete slab down as the foundation for your shed. This article will act as a little guide to concrete slabs for sheds and why you should always be pouring the slab before erecting your shed. We’ll also look at the best mounting points, before providing some useful information on why you should be hiring a professional for the job.



Should You Pour The Concrete Slab Before, Or After Building The Shed?

This is a question we get asked quite a bit, and there’s a number of important reasons why you should always pour the slab before building your shed. Unfortunately, there are many shed builders that will first construct your walls, then pour your concrete slab in. This can be a costly mistake as it can cause premature corrosion of the shed.

Whilst you may see some cheaper quotes from a number of businesses, the process of pouring slab after building the walls is not a route you want to take. In the long run the costs of replacing your shed due to the shed rusting away, will be far greater than establishing a solid foundation right from the beginning. At Spinifex we pour the concrete slab first, making sure you can take advantage of our full warranty for the shed we construct.

With the walls of the shed being put up first, they are exposed to accelerated corrosion caused by the wet concrete reacting with the shed materials. Furthermore, the cured concrete shrinks- causing a build up of dirt and debris in the gap left between the shed walls and the slab itself. Pouring your slab in first helps to significantly reduce the risk of corrosion, and is something we always recommend for every shed project.

What’s The Shed For?

A quick side note, but still something important to think about is what the shed is going to be used for. If you’re planning just storing the mower, maybe a spade or two, the concrete just needs to be smooth and unlikely to move. However, if you’re planning on installing a car hoist or other heavy machinery in the shed, remember to consider the required concrete depth,and how easy it’s going to be to achieve this depth if you’re pouring the slab after!

Consider Your Mounting Points

Once you have poured your slab, you’ll need to think about how you are planning on attaching the shed to the concrete. The size and material of your shed will help to inform which mounting points will be best for you. As you have answered what the shed will primarily be used for, you should have a better understanding of the ideal mounting points and where they should be positioned for your convenience and structural integrity.

Essentially, there are three main ways of connecting the shed’s columns to the slab, and they vary in effectiveness. You’ll need to think about the climate where your shed is going up, and how long you want it to last when choosing a mounting method- if you’re in an area that sees regular cyclones, make sure it’s bolted down as firmly as possible.

Dynabolts are the easiest, quickest and cheapest way to mount your shed to the slab. Realistically, they’re the weakest of the three but need the least fiddling. Drill a hole into the slab, and slot the bolts in. Tightening up the thread will cause the outer shell to expand, and bite into the concrete. One of the downfalls with dynabolts however, is that they can fail to grip, damaging the concrete and widening the hole. Once it’s too wide, they won’t grab at all. This is particularly a problem in weak or poorly laid concrete as it’ll crumble and the dyna bolt won’t hold. Hope it doesn’t get too blowy when a storm rolls in.

Better than dynabolts is chemset and threaded rod. You start off by drilling a hole into the slab, before dropping a threaded rod into it and securing it with chemset. Chemset is stronger than dynabolts, and is basically cement epoxy that sticks real tight. Then, you’ve got a bolt glued directly to the slab to which you the posts can be affixed with a regular nut situation. Chemset holds better than dynabolts, and is maybe slightly more involved as a process. Overall though, when tying a shed down if they’re your only two options- the chemset and threaded rod will give you more security and a firmer hold.

Finally, the ultimate way to fix your shed to the ground is with cast-in stirrups. They’re pretty much exactly what they sound like, a mounting point that is inserted into the wet concrete or set up prior to the initial pour- either way they’re part of the slab. This means they’re virtually impossible to remove, short of cutting the whole section out. Obviously though, they need to go in prior to the shed going up, which means the margin for error is significantly lower- there’s no take backs once the concrete sets. Having said that, they are also the easiest to install, assuming you get the measurements correct!

One of the most common and effective mounts for sheds in Australia involves using a saddle and bolt set. The saddles themselves sit on top of the concrete and are bolted into the concrete for maximum strength and security. These are the types of mounting points that we recommend as no other type will give you the longevity that in-concrete saddles will provide. The saddles will need to be installed in the concrete before it has fully cured. If you are planning on installing a car hoist this is the opportunity to install additional saddles and bolt anchors for the hoist to attach to.

Consider A Professional For The Job

If you’re overwhelmed by the whole process, or don’t exactly know what shed or concrete will be best for your situation, it’s best to consider a concreting and shed specialist for the job. The experts at Spinifex offer a package solution whereby we will pour the concrete slab, construct the shed, and (in the case that you need one) install a suitable car hoist for you. We’ll use in-concrete saddles for mounting points to help achieve maximum strength for your shed, so you won’t need to worry about its structural integrity.

By choosing Spinifex Sheds Perth for the job, you’re ensuring you are having a quality job taken care of by experienced professionals, allowing your shed to have a greater lifespan and continued use over the years. Contact us today to discuss our exclusive shed and car hoist package deal.