How to tell whether your wall is load-bearing

Almost every enquiry about opening up a downstairs starts with the same sentence: I think it might be load-bearing. Here is how to read the signs yourself, and why the answer still has to come from someone else.

Which way do the joists run

This is the strongest clue in most houses. Floor joists span the shortest distance and rest on the walls at each end. If the joists above run into your wall at a right angle, that wall is very likely carrying them. If they run parallel with it, it may not be.

You can often work the direction out from the floorboards upstairs, because boards are laid across the joists, not along them. A loft hatch is the other easy look.

Is there a wall directly above it

Load has to travel down to the foundations in a straight line. A wall that lines up with another wall on the floor above is usually doing something. One that sits under nothing in particular may still be, because it might be carrying the joists even without a wall above.

How thick is it, and what is it made of

A stud wall you can knock and hear hollow is often, but not always, non-structural. Blockwork or brick in the middle of a house is usually there for a reason. In older Bridgend terraces the internal walls are frequently solid, and in 1970s estate houses they are frequently not.

Why none of this settles it

Every one of those signs has exceptions, and the exceptions are the expensive ones. A wall can look like a partition and still be propping a purlin. A ceiling can be held by a beam nobody knew was there.

A structural engineer decides it, calculates what has to replace it, and building control inspects the work. That sequence is not optional and it is not expensive relative to getting it wrong. If a builder tells you a wall is fine to remove without an engineer looking, that is your answer about the builder.