How to Lay a Concrete Base
Concrete is a fundamental building material that is used in the construction process of all types of buildings, structures and other construction elements.
Durable, robust and resistant to abrasion, whether you’re conducting a domestic project or significant commercial work, understanding how to properly lay a concrete base is a key skill and one that everyone should know how to do properly.
Here at Concrete Supply UK, we frequently supply a wide range of concrete products to customers across the nation, always tailoring our mixes to the exact needs of our customers to ensure they can achieve their desired results.
With this in mind, our team are concrete experts, and in addition to supplying these bespoke mixes, we have the knowledge and expertise needed to carry out any concrete construction task.
We know exactly how to lay a concrete base, and in this article we will outline the specifics of the task, explaining how you can complete the work in a seamless and hassle-free way.
Read on to find out more.
What is a concrete base?
Before we explain how to lay a concrete base, let’s first outline exactly what a concrete base is.
In short, a concrete base is a common structural element that is used during the construction of all types of modern buildings and other types of structures.
Usually, a flat, horizontal surface will be laid which is made from concrete. It provides a strong base for whatever is being built upon it, while also offering a consistent and level surface.
Benefits of a concrete base
A concrete base offers several benefits when it is used in construction and landscaping projects. These benefits include:
- Strength and durability – Undoubtedly the biggest benefit of concrete, especially when used as a base, is the strength and durability it offers. Concrete is one of the most robust materials around and a concrete base provides a solid foundation for structures, ensuring stability and excellent longevity.
- Stability – Staying on the theme of stability, this is a quality you can always expect when a concrete base is being used. The excellent stability they provide makes concrete bases ideal for supporting heavy structures such as buildings, bridges and retaining walls. They can withstand the pressures exerted by the weight of the structure and external forces like wind and seismic activity.
- Resistance to weathering – Concrete is resistant to adverse weather conditions, and this is a great advantage, especially here in the UK where we get plenty of rain, wind and sometimes snow and extreme temperatures. This resilience ensures the longevity of any structure that is being built upon the concrete base.
- Low maintenance – Once it has been properly constructed, concrete bases require minimal maintenance compared to other materials. They do not rot, warp or decay like wood and they can also resist damage from pests like termites and other insects.
- Fire resistance – Concrete is an inherently fire-resistant material, making it a safe choice for structures where fire protection is a concern. In the event that a fire does occur, this helps the blaze to be contained and prevents it from rapidly spreading.
Overall, the benefits of a concrete base are wide-ranging and include strength, durability, resistance to weathering, versatility in design and more. They’re also extremely environmentally friendly and it is these factors that make concrete such a popular choice as a base for various construction projects.
What can be built on a concrete base?
Now, let’s turn our attention to the types of structures you can expect to see built upon a concrete base.
These include:
- Buildings
- Bridges
- Retaining walls
- Outdoor structures (like garden sheds)
- Swimming pools
- Car parks
- Roads
- Sports facilities
- Foundations for equipment
- Utility structures
- And much more
Concrete bases are extremely versatile and are regularly used in various construction projects across the country.
How to lay a concrete base
Laying a concrete base is a construction task that is performed in building sites throughout the UK on a daily basis.
As well as frequently being used in commercial projects, it’s likely that any domestic DIY work will, at some point, see a concrete base needed. With this in mind, we’re going to explain how to lay a concrete base, providing you with a step-by-step guide on how to effectively do so.
Simply follow the steps below, and you will have a quality concrete base that is ready to use. For the purposes of this guide, we will be discussing laying a concrete base in the context of constructing a new garden shed. This is because it is one of the most common domestic projects that requires a concrete base.
Gather your materials
Before you start laying the base, you should gather all of the necessary materials that you’re going to need to do the job.
This includes:
- Your concrete mix
- Your sub-base
- A damp-proof membrane
- A tape measure
- A spirit level
- A set square
- A spade
- A rake
- An edging trowel
- Timber
- A saw
- Pegs and string
- A wheelbarrow
- An earth rammer
- A plastic sheet
This list is not exhaustive, and depending on the specifics of your project you may need some additional equipment but the above is likely enough to get the job done.
Prepare the base
Once you’ve got all of your equipment, it’s time to prepare the base.
This is an essential step and should not be skipped. If the base you are working with is not completely level and stable, then you will likely discover that the shed will warp over time.
Therefore, review the space you’re working with and make sure you select the most level part of the area.
Mark and measure
Once you’ve decided where the shed is going to go, you need to begin marking out the area. To do this, use your pegs and string to create a square based on the dimensions of the shed. Hammer your pegs into the ground and connect the string.
Measure the lengths between opposite corners to ensure that all of the angles are equal and the sides are completely straight. It’s worth making the square slightly larger than what the shed is going to be as this will give you some wriggle room to work with. However, don’t make it too big. This is because once the concrete rim is installed, rain will bounce off it and onto the shed which can cause damp problems in the future.
Dig the base area
Now it’s time for some elbow grease!
If you’re building a small shed, dig around 175mm (or 7’’) deep or if you’re working with something larger you should dig to a depth of 225mm (or 9’’). Remove any vegetation, stones or other debris that could cause the base to become unlevel and then, if necessary, compact the earth to make it as stable as possible. Try and keep the depth as consistent as you can as this will help you to achieve a level base.
Then, remove the string and pegs.
Lay your sub-base
It is not possible to lay a concrete base directly onto the soil, and this is the stage when you will need to lay a sub-base.
Usually, MOT is the preferred sub-base type that is used in these kinds of projects. This is because it is extremely hard and robust and so provides a solid foundation for your concrete base.
Measure the timber rails
Now, you need to measure and cut your timber into the shape of a slab that will act as the rails for the base. It is important that you do this as precisely as possible as if it is not level on all sides it will not work.
Position the frame where the base is going to go. Drive wooden posts into the ground around the framework at one-metre intervals. This will ensure that when the concrete is poured the planks won’t break from the weight. Use your spirit level to check everything is level before you proceed.
Apply your damp-proof membrane
Next, you should install the damp-proof membrane. This material will sit on top of your sub-base and will both prevent your concrete from dying out too quickly and also stop any future damp or condensation issues within your shed.
Pour your concrete
Now, it’s time to pour your concrete mix.
Depending on the type you’ve selected you may need to mix it first, but if you’re using ready-mix concrete you will be able to apply it straight to the area.
Move the concrete in wheelbarrows if required, and level it out using a shovel or rake. Once all the concrete has been poured, use a piece of wood to level the mix and remove any air bubbles.
Allow the concrete to cure
You cannot get to work on the base until it has dried, so you should allow some time for it to cure before placing your new shed on top of it.
It will take around 48 hours before the base is dry enough to walk on, and you can remove the timber formwork after this period. However, it will take up to 28 days before it is capable of withstanding the weight of a shed.