Dont install on Gravel or Concrete
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Why Not Put a Shed Directly on to Gravel or Slabs?

Here at The Shed Base Company we get asked many different questions by our customers, but one of the most common questions is this:

“Why wouldn’t I just put my shed directly onto hardcore, gravel, soil or slabs?”

And we understand why. For so long, sheds have simply been placed directly onto the existing grass or soil surface or onto pre-prepared bases made of slabs, poured concrete or hardcore. Why is this the case I hear you ask! Well, historically, an alternative wasn’t available and so people generally made the best of what they had and looked to find the most cost effective method.

As modern plastic moulding technology has improved no end over recent years, manufacturers are now able to produce plastic products which are incredibly strong and durable. This means that we are seeing a huge increase in plastic replacing traditional materials such as concrete, tarmac and bricks.

In this article

Our plastic shed base range is perfect for garden buildings of any size or type!

Browse Shed Base Range

The switch to plastic means that now, products such as our plastic shed base tiles are much more accessible as they are much easier to handle, transport and install. This switch has saved people countless labour hours, huge sums of money and reduced both the amount of plastic going to landfill and in turn the amount of carbon dioxide produced as a by-product of the manufacturing process.

“That’s all well and good but why would I use a plastic shed base instead of just putting the shed straight onto compacted hardcore?”

Simply put, our plastic shed base panels have been designed and engineered to not only support the weight of your shed, but also to help prolong the life of any wooden structure placed on top. How does it do this? Let’s break it down into the benefits:

Plastic Shed Bases Don’t Absorb Water

It’s quite common knowledge that water is one of the most destructive forces that can come into contact with wood. Unfortunately for sheds, there’s plenty of the wet stuff knocking around in the UK! Our plastic shed bases are designed to be filled with gravel (but can be left unfilled while still achieving the same goal) which allows water to pass through the surface without absorbing any of it.

As both the plastic shed base and the gravel-fill contained inside of it are not porous, they do not absorb any rainwater and simply allow the water to pass straight through the top, soaking into the floor below and dispersing away in the most natural way. This process actually helps to improve the quality of the water too as some of the pollutants in rainwater get captured by the gravel and soil below and naturally break down.

Again, as the plastic is non-porous, the water will not be soaked upwards from the ground and brought into contact with the bottom of the shed. This helps to prevent the shed from rotting from the bottom up, unlike a shed placed directly on hardcore which will suffer from water being soaked up from the bottom of the shed as the wooden shed bearers are in direct contact with the ground.

If a large amount of rain falls in a short period of time or the drainage of the soil is not particularly good, the rain can form puddles and these often gather around structures such as sheds. This puddling often gets absorbed by the shed bearers and poses a threat to the shed as more moisture soaks into the wood and over time causes rotting and the natural break down of the wooden fibres.

As concrete slabs are not permeable (but are slightly porous) they will absorb an amount of water as well as doing nothing to combat puddling. So when the rain falls, concrete will not only trap water around the base of your shed, it’ll also continue to allow water to soak into the shed from within the slab itself.

Settlement/Sinking is Prevented by a Plastic Shed Base

As the rain falls over the years, the ground goes through a continual wetting and drying process. If a shed is placed directly on grass or soil, this can mean that the ground becomes saturated and starts to be moulded or indented by any heavy items placed on it. This results in a sinking effect that doesn’t always occur evenly across the whole area of the shed, often with one corner or side slipping into the soft ground below.

The shed then becomes uneven and puts intense strain on the construction of the beams and slats and can cause the shed to start to break up and puts it at risk of damage from wind.

If placed on compacted hardcore, the problem is still present but will take longer as the sandier material washes out of the hardcore and into the soil surrounding it. This then causes unevenness and can only be rectified by lifting the shed and building the washed out areas back up to ensure its strength and stability.

Plastic shed base panels interlock together to create one continuous surface, supported by a compacted hardcore base. So even if there’s localised wash-out of the sandier material in the hardcore (which can be vastly reduced by using a membrane in the build-up) the grid will help to bridge the gap while still offering strength. Of course, plastic does not become weathered or soggy in wet weather, giving you a solid base all year round.

Plastic Shed Foundations Promote Air Circulation

Placing a shed directly onto hardcore or concrete slab bases effectively traps a pocket of air between the base of your shed and the ground. This air pocket can become quite moist and the moisture then condenses on the wooden base of the shed, posing a risk of rotting from the bottom up.

Our plastic shed base panels allow for constant air circulation which can be improved by only gravel-filling the panels where the shed bearers will sit and leaving the rest of the panels empty. This will aid the air circulation and will help to keep the base of the shed dry and will prevent rotting.

7 Replies to “Why Not Put a Shed Directly on to Gravel or Slabs?

  1. I am considering a plastic shingle filled base for a large 24 feet by 10 feet by 7 feet tall workshop. The principals of the support offered by aplastic base i understand however will the width of the shed floor bearers if to narrow possibly crush the plastic before the shingle takes the load

    1. Hi Peter,

      Thank you for your comment. Our shed base panels are tested to withstand 420 tonnes of compression per square metre, when the panels are unfilled. Therefore when the panels are filled this loading capacity increases. The panels have been installed by thousands of customers and we have yet to hear of a single incident where the panels fail due to over-loading.

    1. Thanks for your question.

      Yes, these bases are both made from recycled plastic and they can be recycled at the end of their natural life.

    1. Hi Coral,

      As long as the area is level and solid then our plastic bases would be suitable. You can see our base being installed on a concrete area in one of our previous blogs: 10ft x 6ft Plastic Shed Base Installation.

      Hope this helps, if you have any more questions please call us on 01246 589021 or LiveChat during office hours.

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