Robust and quick to install, this system could be the best choice for your selfbuild project – and not just for the ground floor, says Mike Hardwick

Mike Hardwick

One of the best decisions I made when self-building my own house was to specify beam and block intermediate flooring. I touched on this a few issues back when I listed my 10 favourite things about my project. So this month I thought I’d expand on the subject and explain in detail why this system is such a good choice, not just at ground floor level but also for upper storeys – at least where it’s practical for your scheme.

Oversite options

Once the footings are in, you’ve got a choice in terms of what you use as the platform (the oversite) on which your home will be built.

Years ago, the simplest solution was to fit timber joists covered in floorboards. But suspended timber structures can be draughty and noisy, so they won’t suit modern self-builds, where decent levels of insulation and airtightness are required.

The most straightforward option today would be a concrete slab laid on top of compacted hardcore. The latter would be covered with a layer of sand (known as binding) to protect against sharp edges, plus rigid foam insulation on a damp proof membrane. While this is a common choice, the labour requirement is reasonably high – plus you’ll need to wait for the concrete to cure before work can continue.

New systems appear all the time. Fully-integrated insulated slabs are now a popular choice on high-spec eco homes, for example. Even more common, however, is the use of beam and block for the oversite – and potentially intermediate floors, too.