how to build a shed base

How To Build A Shed Base

What exactly is a shed base?

A shed base is one of the most important things to consider when you are building a shed, regardless of the type of construction you are building or the material you are using to make it. It is the very foundation that your shed will be built upon so it must be made properly if you want it to stand the test of time. To most of you the idea of building a shed base for any type of garden building may seem a little daunting, but there are ways to make it easier on yourself. You just need to know how.

Why do you need a shed base?

This is a popular question that many people ask when contemplating investing in a shed or other outbuilding. The simple answer is, if you don’t have one your shed is in danger of becoming unstable and may quickly fall into disrepair. Regardless of the size of outbuilding you are erecting, getting a solid foundation is vital if you want a long lasting and stable construction.

The problem is, for many it can seem like an incredible hassle to spend the time, effort and money making a solid foundation for their shed when they could just erect the shed and place it on the ground. What could go wrong?

Well, the answer is many, many things. Let’s say you have a level lawn that you want to put a shed on. Because the lawn is level you think placing it directly on the grass will be find and there is no need for a shed base. So, you spend the time and effort erecting the wooden behemoth and plant it on the lawn. Initially everything seems fine. You built the shed in summer when the ground was hard and it seems stable. But then autumn comes and with it rain. The grass gets wet and the floor muddy. The floor subsides a little and the shed begins to list or rock when you are walking inside it. You decide to ignore these problems. But as the seasons progress they become worse. Then after a couple of years, the wood that’s touching the floor begins to rot and becomes a mould magnet. Within a short time the entire wooden structure is so unstable that you are no longer able to use it. The life of the shed has been cut short due to an unstable base and lack of a solid foundation that would protect it from the elements.

You may be thinking, but my shed is made of plastic or metal. How does a shed base help with that? Well, the fact of the matter is, even metal and plastic sheds can suffer instability if they aren’t erected on some form of solid base. Shifts in the ground caused by weather can make any type of garden building look like the Leaning Tower of Pisa very quickly without one.

Different types of shed base.

Not all shed bases are the same and you do have some choice when it comes to picking the type of base you want to use. In a few cases you may not need to install a base at all, but that will depend on the type of flooring already in your garden. For example, if you already have a large area of concrete in your garden this can be used as part of the shed’s base. Paving slabs or stones that are already laid can also often be used as a shed base, but it is essential that they are level before they are utilised for this purpose. For people without either, fitting a shed base will be an essential part of the process of fitting a shed.

Anything I should consider before fitting a shed base?

In a word, yes. Make sure that if you need permission to erect a shed that you have it. It’s not a great idea to spend hours of time and money building an amazing summer house only to be told to take it down at a later date.

Also, make sure the ground where you want to fit it is dry and level.  You wouldn’t want to fit the shed on unlevel ground and equally the shed base needs to be level too to prevent any issues in the future.

Remember not to put the base too close to walls or fences as the roof of the shed may slightly overhang. Also, keep the base away from trees or large bushes as overhanging branches can cause issues in the long term, especially if the trees or bush is likely to grow and come into contact with the building in the future.

So, what are my choices for shed bases?

There are three main popular types of shed base, Eze Base, Concrete Base, Paving Slab Base.

Related: Choosing A Garden Shed

What is an Eze Shed Base?

An Eze Shed Base is the easiest type of shed base to construct. While there are many different types of Eze shed bases, the general concept is the same: a pre-made (or paritally pre-made) base that takes very little effort to build. Before buying an Eze shed base, however, you do need to make sure that the shed you have bought or intend to buy can be used with one because not all will.

How do you build an Eze Shed Base?

In essence you just need to follow the simple instructions that come with it. We would still recommend making sure the ground is level and dry beforehand though.

What is a Concrete Shed Base?

A concrete shed base is an incredibly solid form of shed base and is recommended for any larger constructions. It is made by marking out the foundation base and digging down to fit hardcore before building a frame (called formwork) and pouring concrete into it. The shed is then fixed to this slab of concrete.

How do you build a Concrete Shed Base?

Firstly, get the equipment you need: string and pegs, sand, cement, wood for the base of the shed, a spade, a tape measure.

Step One: Think about where you want the base and mark it out. Give yourself enough distance from things like walls, trees, hedges, garden gates, etc. Use pegs and strings to outline the base but make sure that the outer edges are 5cm bigger than the area of the shed.

Step Two: Dig down and lay a hardcore base of at least 7 cm deep. Use the rake or spade to ensure the area is totally level and then take out the pegs.

Step Three: Create a levelled formwork by chopping the timber to the shape of the base. This will keep the concrete contained when poured. Inside this place another layer of hardcore and cover liberally with sand. Flatten this down preferably with a roller.  

Step Four: Mix concrete with ballast in the ratio of 1:5. You can use a pre-mixed concrete by just adding water if this is easier for you. Water should be added in small quantities and mixed thoroughly into the concrete until you get the correct consistency. Try not to make the concrete too sloppy. Once you are happy with the consistency, evenly spread the concrete inside the formwork until it comes slightly above the top of it. Level off the concrete with straight piece of timber, using the formwork as a rest and guide. Keep the concrete covered for at least 24 hours. If it is to rain use dry polythene. If it is hot, use damp sacks sprinkled with water periodically.

What is a Slab Shed Base?

A slab shed base is a shed base made from paving slabs. The slabs are laid, and the shed is then fixed directly to the top of them.

How do you build a Slab Shed Base?

Firstly, get the equipment you need: string and pegs, paving slabs, sand, cement, a rake, a tape measure, flat edged spade, and a rubber mallet.

Step One: Mark out where you want your shed using the pegs and the string again leaving enough space from trees, walls, hedges etc.

Step Two: Dig off the topsoil to about 7cm in depth and level with the rake. Take the pegs away.

Step Three: Mix the cement with building sand in the ratio of 1:8 and spread it evenly on the levelled area. Ensure this is also as level as can be.

Step Four: Start laying the paving slabs. Start in a corner and work outwards from there. Tap each one into place using the rubber mallet. A spirit-level can be used to ensure each is level.

 Step Five: Fit the shed to the paving slabs.


How to build a shed base on uneven ground

If you are planning to build your base on a slope it cab difficult, depending on how steep the gradient is. You will likely need foundation blocks and in some cases you may need to build a retaining wall.

The final word…

There you have it. Our handy guide to constructing a shed base. Follow these tips and you will be sure to have a shed that will not only look amazing but will be sturdy and more importantly stand the test of time.

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