How much does a concrete floor cost?

If you are looking to build a workshop shed, you will likely need a concrete floor. If so, you may be wondering what thickness floor you need and how much it will cost, the answer is; it depends.

In this article, we discuss the two most common types of concrete floor in New Zealand, the most common thicknesses and how much they cost per square meter.

Structural Concrete vs Non-Structural Floors

There are typically two types of concrete floors used for sheds around New Zealand. The design you’ll need will depend entirely on what type of shed you intend to build.

Structural Floor

Typically, a structural floor will need to be used for any building that bolts or attaches directly to the concrete floor. This means that the concrete floor has to be engineered to take the weight of the building and effectively hold the building up. Any steel building, whether roll form steel or structural steel, will need a structural slab placed before the shed is constructed.

Structural floors are typically considerably more expensive when compared with non-structural floors. This is because they need to be engineered, requiring substantial earthworks and more steel reinforcing. Often perimeter thickening is required, which means a trench must be excavated around the perimeter of the slab and a concrete nib wall must be poured first.

Additional steel reinforcing is required to connect the nib wall to the rest of the pad and this must be poured separately to the nib wall. This can increase the cost significantly as more concrete, reinforcing and time are required. Once the nib wall has been installed, polythene and mesh is laid and then tied into the nib wall reinforcing to connect the nib wall and concrete slab.

Non-Structural Floor 

A non-structural concrete floor is any floor that doesn't take the weight of the building. These are most commonly used in pole sheds as the poles are concreted into the ground meaning the building is not relying on the concrete floor for any strengthening. Pouring a non-structural slab is very simple and is a lot faster to prep and pour.

These floors don't need perimeter thickenings or additional reinforcing, firstly you attach the boxing to the outside of the poles, put a layer of polythene down, lay the concrete mesh and pour the floor. This process saves a significant amount of time in the floor prep and pour, leading to significant cost savings.

how much does a concrete floor cost? 

As discussed above, a non-structural slab is significantly more cost-effective to prepare and pour. A 100mm thick floor is suitable for most sheds and will be sufficient for storage of cars up to medium sized tractors. These floors cost around $110.00+GST per square metre, including polythene, mesh, concrete, and labour to place the floor (assuming a flat compacted gravel pad is supplied). 

150mm floors would be required for truck storage or any larger/heavier equipment. A non-structural floor of this thickness will require polyethylene, slightly heavier gauge mesh and additional cubic metres of concrete. A 150mm thick floor will typically come out around $130.00+GST per square metre, once again, assuming that a flat compacted gravel pad has been supplied. 
 
A non-structural slab is the easiest and most cost-effective slab you can build due to the simplicity of the design. A structural slab will cost considerably more and depending on the size of the shed and what is stored, a structural slab could cost 25% more than a non-structural slab.

Are You Wondering how to prepare your shed site?

If you are looking to build a shed and wondering how to best prepare, click here to find out or to discuss your upcoming project with an expert, talk to the team at Alpine. We would be happy to help you design your dream shed!