Whenever you are planning on doing major work on the walls of your house, you need to know if they are load-bearing or not before you start. Load-bearing walls are holding up your house, and even slight alterations to their structure can cause big problems.
The external walls of your house are almost always load-bearing, supporting the majority of the roof weight and transmitting the load to the foundations.
The internal walls of your house are not so easy to categorise. At least some of the walls will be load-bearing (except in some timber frame houses, etc) but some will also be non load-bearing. It is always a good idea to check with a structural engineer if you are unsure, but here are a few ways to identify load-bearing walls.
Walls which carry the floor joists can be identified by checking the floorboards. The floorboards will be laid across the joists, meaning that they will run parallel with the load-bearing wall. You will need to check on each level as a wall which carries the load of one floor, may not continue up to carry the load of the next (assuming you have more than one floor in your house).
Checking which way roof braces run in relation to the walls is another way to check which are likely to be load-bearing. The braces will run across load-bearing walls and parallel to non load-bearing walls.
The construction of the walls is also a good indication of its ability to bear loads. Load-bearing walls are usually made of bricks or blocks. A stud or partition wall, be it plasterboard or lath and plaster, is rarely load-bearing. However, some stud walls are classed as load-bearing if they add to the stability of the structure, even if they aren’t holding anything up.
Non Load-bearing Walls
Non load-bearing walls are also sometimes made of bricks or blocks, but this is unusual as stud walls are cheaper and quicker to put up for most builders. Non load-bearing walls are usually only the height of one level, so if the floorboards run underneath the wall in question it is probably not holding anything up.
As mentioned before, if in doubt, check with a structural engineer or an experienced builder. Making a mistake about which wall is load-bearing and which is not can lead to a costly disaster.