How to Tell if a Wall Is Load Bearing (and What to Do Next)

Joist direction, walls above, chimney breasts and water tanks all give clues about whether a wall is load bearing. Here is how to read them, and why clues are not proof.

You can often get a good idea of whether a wall is load bearing by checking which way the floor or ceiling joists run, whether there is another wall directly above it, and whether it is an external wall, a central spine wall or a wall holding up a chimney breast or water tank. A wall that runs at right angles to the joists, with joists resting on top of it, is usually carrying load.

Clues are not proof, though. Only a structural engineer can confirm whether a wall is load bearing and specify what replaces it, and removing one needs building regulations approval. Use this guide to have a better informed conversation with your builder and engineer, not as a reason to pick up a hammer.

Why it matters

A load bearing wall carries weight from above down to the foundations. That weight might be a floor, the roof, another wall, a chimney breast or a water tank, and often a mix of these. Take the wall out without proper support and the load has nowhere to go. At best you get sagging floors and cracked ceilings; at worst part of the structure fails.

It is not just full removals either. Forming a new doorway, widening an opening or knocking through for a serving hatch in a load bearing wall all need a properly sized lintel or beam and the right temporary support while the work is done.

Clue 1: which way the joists run

Joists are the timbers that support floors and ceilings. They span from one support to another, and the walls they rest on are carrying them.

• In the loft: look at the ceiling joists of the top floor rooms. If they run across the line of the wall below and rest on it, or are joined or overlapped above it, that wall is very likely supporting them.
• Between floors: lift a floorboard in the room above. Floorboards normally run at right angles to the joists, so even the direction of the boards gives you a hint.
• Joists running parallel to the wall: usually a sign the wall is not carrying that floor, but not always. A doubled joist or a beam can sit right over it, and the wall may be carrying something else entirely.

Be aware that joists can change direction from room to room, especially in houses that have been extended or altered, so check above the actual wall you are interested in.

Clue 2: does the wall continue above?

If there is a wall directly on top of the one you want to remove, on the floor above, the lower wall is probably holding it up. Builders stack walls on top of each other for exactly this reason. A first floor partition that sits over your ground floor wall may itself be carrying the ceiling joists or part of the roof, which makes the lower wall part of a load path running from the roof to the ground.

Clue 3: external walls and spine walls

External walls are always load bearing. They carry the roof and the floors, and any new opening in one needs a lintel or beam designed for it.

A spine wall runs through the middle of the house, usually from front to back, and often carries floor joists from both sides. In many homes the wall between the front and back rooms, or the wall alongside the hallway, is doing some structural work, even if it is only supporting the wall above.

House types vary a great deal. Across Chelmsford, Billericay and Brentwood we work on everything from Victorian terraces to 1930s semis and modern estate homes, and in Basildon there is a large stock of post-war housing, some of it built with less traditional methods. A rule of thumb that holds for one house type does not always hold for the next, which is another reason not to rely on rules of thumb alone.

Clue 4: wall thickness and construction

Knock on the wall. A hollow sound usually means a timber or metal stud partition with plasterboard or lath and plaster; a solid, dull sound usually means brick or block. You can also measure the thickness at a door frame.

• Masonry internal walls are more likely to be load bearing, particularly on the ground floor.
• Stud walls can carry loads too. In older houses, timber stud partitions often support floor joists or the wall above, and some are built as trusses that carry weight across an opening. Do not assume a hollow wall is safe to remove.
• Modern houses with trussed rafter roofs often have internal walls that do not carry the roof, but they may still carry the upper floor.

Clue 5: chimney breasts, water tanks and point loads

Some walls carry concentrated loads that are easy to miss:

• Walls beside or beneath a chimney breast, which can be extremely heavy
• Walls under a cold water tank or hot water cylinder in the loft or airing cupboard
• Walls under the end of a beam or a post, including steels put in by a previous owner
• Walls carrying the landing or the edge of the staircase opening

If a chimney breast has already been removed on a lower floor, check how what is left above is being supported. That is a job for an engineer to look at, not something to discover halfway through a knock through.

Clue 6: original drawings and records

For newer homes, the developer's drawings may show which walls are structural. For any house, previous building regulations applications for extensions or alterations can show what was changed and what was designed to carry load. Your council's planning and building control records, the paperwork from when you bought the house and old survey reports are all worth checking. Remember that past alterations can change what a wall is doing, so the original plans are a starting point rather than the final word.

What happens next if the wall is load bearing

If the clues point to a load bearing wall, or you simply cannot tell, the process is well established:

1. Engineer's inspection and calculations. A structural engineer confirms what the wall carries and designs the replacement, usually a steel or timber beam with padstones to spread the load.
2. Building regulations approval. The work is notified to building control, who inspect it as it goes in.
3. Party wall notice if needed. If the beam bears on a wall shared with a neighbour, the Party Wall etc. Act 1996 may apply.
4. Temporary support, then the beam. The structure above is propped, the wall comes out, the beam goes in and is packed tight, then fire protection and plastering finish the job.

We cover this in more detail on the page for our structural alterations service, and you can see finished examples among our steel beam and structural alteration projects. For a step by step walk through of how a job runs from survey to sign off, read our guide to what to expect from structural alterations.

Even a wall that turns out not to be load bearing can have pipes and cables in it, and removing it may affect your fire escape route, for example where opening up a hallway in a house with a loft conversion removes the protected stair. It is worth asking before you start.

So look at the joists, look above and below, and note anything heavy the wall might be supporting. Then get it confirmed properly before anyone starts swinging a hammer.