Raft Foundations

What is a Raft Foundation?

A raft foundation (also known as a mat foundation) is like a giant concrete blanket that sits underneath your whole building. It spreads the weight of everything above its walls, floors, furniture, you name it, across a wide area, rather than concentrating loads into narrow trenches or individual footings.

It’s called a raft because it kind of floats on the ground beneath, rather than digging deep into it. Sounds simple and it is. But it’s also incredibly smart engineering.

Why Choose a Raft Foundation?

We often recommend raft foundations when:

• The ground is soft or made up of mixed soils

• You’re building something light, like an extension, conservatory, or garage

• You want to avoid deep digging or heavy plant machinery

• Access is tight, or excavation costs are creeping up

• You’re building a basement and need a waterproof slab

Rather than multiple pads or trenches, a single reinforced concrete slab can often do the whole job; quicker, cheaper, and more reliably.

What Are Raft Foundations Used For?

Originally used in big commercial builds (think supermarkets and warehouses), raft foundations have become a go-to solution for domestic builds and extensions too.

You’ll find them used in:

• Home extensions

• Garden offices

• Conservatories

• Basements

• Light commercial units

• Sloping or shrinkable clay sites

• Anywhere with awkward ground conditions

The real beauty of raft foundations? They’re versatile, cost-efficient, and easy to install.

Benefits of Raft Foundations

• Better support for dodgy soils – spreads the weight out so no one bit of ground takes too much stress

• Less digging – ideal for tight spaces or where access is limited

• Faster build times – one big pour and you’re done

• Good value – fewer materials, less spoil to cart off, and lower labour costs

• Even settlement – helps prevent cracks in walls or stuck doors down the line

• Built-in waterproofing – when paired with the right membrane, your foundation is basement-ready

Are There Any Downsides?

No solution is perfect for every project. Raft foundations can be overkill for small, lightweight builds on great soil and on sloped or heavily loaded structures; other systems (like piled foundations) might be a better fit. But we’ll always tell you straight. If a raft isn’t right for your project, we’ll say so.

Why Choose Basetec to Install Raft Foundations?

With over 100 years of construction heritage across the North West, we bring big-project experience to domestic builds of every size. We understand the clay-heavy, waterlogged, made-up ground that makes building in this region especially demanding

From your first call to your final concrete pour, we’ll guide you through the process in plain English, no jargon, no surprises.

• Free site surveys
• In-house design team
• Experienced crews
• Fully insured and guaranteed work
• Foundations that last for generations

Need Some Advice on Raft Foundations?

If you’re wondering whether a raft foundation is the right choice for your build or just want an honest opinion before you go any further, get in touch.

Call us:  01204 840 238
Email: info@basetecpiling.co.uk