A Guide To Strip Foundations

Here at Concrete Supply UK, we regularly supply domestic and commercial customers with quality concrete mixes that are formulated specifically to their needs.

This includes concrete for foundations which is one of the most important types in the industry.   

The role of foundations should not be understated. 

They are designed to support the weight of structures that are being built, ensuring they are structurally sound and will be safe for people to reside or work in. 

There are all kinds of different foundation types, and at Concrete Supply UK we can provide our customers with the perfect mix no matter what foundations you need to build. 

Strip foundations are one of the most popular foundation types around, and in this article, we’ll outline everything you need to know about them.

Read on to find out more…

What Is A Strip Foundation?

Let’s begin by outlining exactly what strip foundations are. 

Also often referred to as strip footings, a strip foundation is a type of shallow foundation that is typically used in the construction of low to medium-rise residential buildings. They provide a strip of support for linear structures and walls, or columns that are narrowly placed, to be built on top of the foundation and installed centrally along the length. The specific location and size of the strip foundations will greatly depend on the exact size and width of the load that is being placed on top of it. Usually, the width of the strip will need to be at least two or three times the width of the structural element that it will be supporting. 

And in terms of the depth, it should be at least equal to, or ideally more than, the width of the wall it supports. The depth of the foundations will also be dictated by the environmental conditions, such as frost, which may impact the ground. 

Strip foundations are most suitable in areas where there is a relatively high load-bearing capacity and where the ground conditions are stable.   

As previously mentioned, strip foundations are a type of shallow foundation. 

Shallow foundations are a popular building foundation that is known for transferring structural loads to as close to the surface as possible rather than deeper in the ground. Usually, this will be the lowest part of the new structure. 

Types Of Strip Foundations 

There are several different types of strip foundations. In the section above, we’ve provided you with everything you need to know about conventional strip foundations, but there may be circumstances where more specialist options are required. 

This includes:

Deep Strip Foundations 

While shallow foundations, like strip foundations, usually need to be closer to the surface, deep strip foundations provide you with an option that goes deeper into the soil. This maintains a suitable load-bearing capacity, and a wider trench will be dug in order for the foundations to be poured at a lower level. 

Then, masonry walls can be built up to just below ground level and the trenches will be backfilled in layers to the finished ground level using new, clean subsoil.

Wide Strip Foundations 

If the soil is unusually soft or has a low load-bearing capacity, then wide strip foundations may be the best option for your project. These foundations are spread across a larger area and are then reinforced with steel to enhance how much the foundations can withstand and that the loading per square metre is reduced. 

Offset Strip Foundations 

If it is not possible to use conventional strip foundations due to the fact that a new structure is being built close to an existing building or access to land is difficult, you may still be able to successfully complete the project by using offset strip foundations. 

You can use a 750mm wide and 450mm deep mesh that can be placed in the bottom of the concrete with a 50mm cover to the steel. This is normally a good solution if building single-storey structures. 

Trenchfill 

While not a strip foundation, trenchfill foundations are the most commonly used alternative if traditional strip foundations are not applicable. 

Trenches are dug and filled with concrete to a depth that is just below ground level. This means that the first material can be laid easily, and with a damp proof course that protects the future structure. It is slightly more expensive though, as more concrete is required to fill the trench and steel reinforcements may need to be added. 

Benefits Of Strip Foundations 

Strip foundations are a common type of shallow foundation that are used to support linear structures such as walls or rows of columns. As mentioned above, they are characterised by a continuous strip of concrete that spreads the load of the structure across the length of the foundation. 

Some of the main benefits of these foundations include:

• Cost-effective: This foundation type typically requires less concrete and reinforcement compared to deeper options and this makes them a more economical and cost-effective choice for projects – especially when it comes to projects where suitable soil conditions are in place. They also do not require as much labour which also helps with cost.

• Speed of construction: The design and construction methods used for strip foundations are extremely straightforward, and this allows for faster construction time which is especially beneficial if you’re working to a tight deadline.

• Even load distribution: Strip foundations distribute the load of a structure evenly along the length of the foundation, reducing the risk of differential settlement and future structural damage.

While there are several advantages to strip foundations, it is also worth noting that they are only really suitable for small-scale construction projects where a relatively low load needs to be supported. If the soil is weak or irregular, you should avoid strip foundations as it could result in the structure not being supported properly – and in severe cases, it may even collapse.    

If you need a bespoke concrete mix for strip foundations or any other type of concrete, Concrete Supply UK is here to help. We can provide you with quality products that enhance every project you’re working on. Simply get in touch with our team today to find out more.