A Complete Guide on How to Build a Shed Base

how to build a shed base

Last Updated on July 26, 2021

A firm base can hold a heavy shed sturdily for a long time. If you have a stable base, it will also be easier for you to fit and assemble the other parts of the shed.

A shed base can be constructed from a wide array of construction materials. Some of the most prevalent and effective shed bases include timber bases, paving slabs bases, concrete bases, and plastic bases. In this post, we will show you how to build a shed base from different building materials.

Factors to Consider Before You Build a Garden Shed Base

Access Points

A shed or any other garden building should be constructed in a spacious area that can be accessed easily. Also, a garden building should be accessible from different directions. For instance, if you plan to preserve it with some paint, a shed that you can easily access from all sides will make the painting job a whole lot easier.

In addition to this, we do not recommend that you construct a shed next to another structure like a wall or any other garden building (log cabins and summer houses). While garden buildings, log cabins and summer houses might be constructed in different gardens, they should be away from other garden sheds.

Electrical Fittings

Unless you’re a qualified electrician, we recommend that you contact a professional if you are planning to install electrical wires in your shed.

Natural Light

All garden sheds should be constructed on spots with enough sunlight to light up the whole shed, making it easier for you to complete your various DIY tasks. Additionally, if you choose not to install any electricity, the content of your garden storage unit will be much easier to identify.

Step by Step Guide to Building a Shed Base

Concrete Shed Base

A concrete base might be ideal for you if you are planning to construct a large garden shed.

Step 1: Clear the Plants From the Ground

Start by clearing the plants and vegetation on the ground where you are planning to build a garden shed on. After that, set out the area you will be working on with some pegs and a string. The string should cover the area where the concrete shed base will be positioned when it is constructed. Ensure that you get all the angles and corners as exact as possible.

Step 2: Excavate

Once you set out the area you will be working on by using strings and pegs, remove the topsoil from that section to about 150mm to create a foundation for the shed base.

Next, pour the hardcore mixture into the trench that you had excavated earlier on to create a sturdy bed for your shed building. Pour it to a thickness of about 75 mm. If the hardcore is unevenly distributed on the surface, you can flatten it with a rake. After that, compact it gently to get an even surface that can hold the weight of the whole shed building. If you don’t like using hardcore, you can also use brick rubble.

Fix some wooden boards around the designated area using a spirit level to check if the surface is completely flat or not. These will shape the concrete base.

Once you finish fixing the boards around the perimeter of the area you are working on to create a frame, you have to prepare a concrete mixture. To increase the concretes strength, you can mix it with water and ballast. Most concrete bags have certain instructions that can give you insight into the different mixing ratios of concrete, ensuring that you read these before beginning your project.

Step 3: Pour the Concrete

Once the concrete mixture is ready, you can pour it into the foundation of the shed base. Ensure that you pour it evenly on all sections and keep on pouring the concrete until it levels out with the upper part of the wooden frame. Smoothen the upper surface and even out any bumps with a metallic, wooden or plastic float.

Paving Slabs/ Paving Slab Design

When choosing paving slabs as a base, follow the below steps.

Step 1: Clear the Grass

Start by clearing the grass and vegetation in the area in which you are planning to install the shed base.

Step 2: Measure, Mark, and Set Out the Area

Once you finish clearing the section where the shed will be, set out the area and the size of the shed base with pegs and strings. As with the cement option, ensure that you work accurately.

Step 3: Remove the Topsoil

Next, excavate the topsoil that is in your lawn or garden to around 65mm. Pour cement mixture into the excavated garden trench, thereby creating a sturdy sub-base for the slabs. You can mix high-quality cement with coarse sand at a specific ratio (1:8) to get an effective cement mixture that can secure the slabs to the ground. Distribute the cement evenly on the trench, using a rake and use a spirit level to ensure a flat surface.

Step 4: Lay/Fix the Paving Slabs

Place the paving slabs on the sand and cement bed from one corner to another. Once you place the paving slabs on the sand and cement sub-layer, tap them slightly, using a rubber mallet to secure them to the ground. Remember that the paving blocks should be placed at a high elevation to boost the drainage in the paving slab shed base.

Wooden Shed Base/ Timber Shed Base

Step 1: Clear the Area

Like other shed base construction techniques, you have to clear the area you plan to work on before starting this procedure. Once you get rid of the undergrowth, shrubs and grass, you will have an easier time making a shed base.

Step 2: Measure, Mark, and Set Out

Afterwards, set out the area that you want to position the DIY shed base, using a string and some pegs.

Next, remove the topsoil to a depth of about 50mm and fill the trench with gravel, creating a 40 mm thick layer.

Check if the gravel has an even and flat surface, using a spirit level. If some sections are irregular and uneven, work on such sections, using a rake to prevent errors as you are building your shed.

Step 3: Lay Some Bearers on the Ground (Concrete or Pressure-Treated Timber)

Place pressure-treated wood bearers on the gravel bed, then space these pressure-treated bearers at an even distance. With these bearers, it will be easier for you to construct a timber shed base. Alternatively, you can use concrete bearers while constructing larger sizes of timber shed bases. Concrete bearers are quite effective in supporting heavy loads in comparison to timber. Not to mention, such bearers can withstand harsh conditions and last for a long time.

The total number of bearers required to construct a shed base will vary based on the shed size, so ensure that you know how many bearers your shed requires.

Drive the bearers slightly into the gravel bed with a rubber mallet so that they are securely nested. All the bearers should be driven to the same depth to ensure you get an even base. Once you secure the bearers on the gravel bed, check whether the bearers are in line and on the same level.

After that, you can either screw or nail a wooden floor to the bearers you just installed.

Plastic Shed Base Installation

If none of the above options takes your fancy, why not try out a plastic shed base?

Step 1: Measure, Mark, and Set Out the Area

Determine the section that you are going to construct the plastic shed base on. After that, measure and set out the area where you will be installing the plastic shed.

Step 2: Excavate

As with the other bases, you must now excavate the top layer until you get to a depth of 80mm100 mm. Ensure that the excavated sub-surface is flat and even on all sections.

When you’re happy that the excavated section is flat, pour some gravel into the trench to create a firm foundation. Next, compact the gravel bed, using light force to get a flat, solid and even surface.

Step 3: Assemble the Plastic Grids

The components of plastic shed bases (grids) have to be placed on another material other than gravel to enhance their durability.

Once you find a plastic sheeting that perfectly fits the gravel bed, spread the sheet on the gravel bed. Then, place the plastic grids on the plastic sheeting, and join the plastic grids to minimise any movements. You can do this by using the clips that often come with the plastic grids pack.

Once you feel that the plastic grids are stable enough, a wooden floor can be fitted on top.

Build a Base With Your Gardening Tools

And there you have it, everything you need to know on how to build a shed base.

Though it may sound like a lot of hard work, building a shed base is not as daunting as it sounds. Basic gardening tools can tackle different tasks such as compaction, levelling and excavation, making it easier for you to put up a base that suits you the most. On that note, a base can be easily constructed from a wide array of different materials. Just ensure you lay the materials out carefully so that you can get an effective and level base.

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