Is my wall load-bearing? How to tell (and how to be sure)

The quick checks

You can get a strong hint without opening anything up. In the loft or the floor void, look at which way the joists run: walls that joists rest on, or run perpendicular to, are usually carrying them. Walls that continue on the floor above are usually carrying that wall too. The central wall running the depth of a terrace or semi — the spine wall — is nearly always structural.

• Joists bear on it, or run at right angles to it
• The same wall continues on the floor above
• It's the central spine wall of the house
• It sounds solid when knocked (brick/block, not hollow stud)
• It's over 100mm thick when you measure at a doorway
• The roof structure (purlins, struts) bears on it via the loft

Why the quick checks aren't enough

Plenty of stud walls are load-bearing — modern trussed roofs sometimes bear on timber stud walls, and older houses often have studwork carrying ceiling joists. Equally, some brick walls carry nothing but their own weight. Houses that have already been altered are the real trap: a previous owner's 'non-load-bearing' wall may be doing a job nobody documented.

The only safe answer is an inspection by a structural engineer or an experienced structural contractor who can see the joist directions, what's above, and how previous alterations were done. That inspection is a standard part of our free survey.