Notes
What actually happens when you take out a wall
The wall is doing a job. Here is where that job goes when the wall does.
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Is my wall load-bearing?
Nearly every kitchen-diner in Britain starts as two rooms with a wall between them. The first question people ask us is whether the wall is load-bearing. The more useful question is what the wall is carrying, because that is what sets the size, the weight and the cost of everything that replaces it.
The answer usually turns on one thing that costs nothing to check: which way the floor joists run. A wall that the joists land on is carrying floor. A wall that runs the same way as the joists is carrying whatever stands on it, which is often the wall above and everything that wall holds up. The second kind is the one on the model below, and it is held up in a different way while it comes out.
Carrying weight is not a wall’s only job. One that runs across the house, parallel to the front, like this one, also braces it, stiffening the walls at its ends against the wind. Taking most of it out means checking the house is still braced without it.
The new steel beam (often called an RSJ) on this job is a flush one. It sits within the floor, among the joists, rather than hanging below the ceiling as a downstand, which is why the propping is arranged the way it is. Below, it all happens in the order it does on site: scroll, or step through it.
Step by step
From wall to beam, in the order it happens
The model is a photograph of an ordinary two-storey house cut through in section. Everything drawn over it is the engineering.
01 of 08
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What this wall is doing
Start with the floor above, not the wall. The section cuts straight through the first-floor joists, so what you are looking at is their ends: a row of them, evenly spaced, from the front of the house to the back. They run across the house, parallel to the front, and land on walls beyond this cut.
This wall runs the same way they do. The joists pass alongside it and put nothing on it. What it carries is the wall standing directly on top of it, and whatever that wall is carrying.
Holding a wall up is a different job from holding a floor up, and it changes what has to happen to take this one out.
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Which way the joists run, and why it decides everything
Here is the rule the whole job turns on. If the joists land on a wall, that wall is carrying floor. If the joists run the same way as the wall, they are passing it, and the wall is carrying whatever stands on it instead, which may be a great deal or may be nothing at all.
Direction is usually readable from inside the house. Floorboards run across the joists, so the boards tell you the joists lie at right angles to them. In a loft the joists are in plain view. An over-boarded ceiling gives itself away by where the screws line up.
Get the direction wrong and every answer after it is wrong: what the wall is carrying, what has to hold that up while the wall comes out, and how big the beam needs to be.
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Where the load goes
Follow the weight down. A roof strut puts load into the first-floor wall. That wall carries it, and its own weight, straight down onto this one. This wall takes all of it to the foundation, and the foundation spreads it into the soil.
The floor is not in that line at all. It is running past, into the page, to walls beyond this cut.
That route is the load path. Remove a link in it and the load does not go away. It has to be given a new route, and someone has to work out what that new route can stand.
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Needles through the wall above, props up through the floor
A prop under the floor would do nothing here, because the floor is not what is being held. What has to be held is the wall above the opening. So the wall is picked up by needling: a hole is cut through it, a short stiff beam called a needle is passed through and packed tight to the brickwork above it, and a prop is set under each end, one on each side. This cut shows one needle; along the wall they repeat at spacings our design sets.
The needle goes through the wall on the first floor, above the floor structure, rather than through the wall that is coming out. That is deliberate, and it is what makes the rest of this possible. The new beam is going into the depth of the floor, so the joists and the space between them have to be left clear for it, and the temporary works have to stay out of the band the steel will occupy.
Which means the props start at the needle ends, on the first floor, and come down through holes cut in the floor to reach the ground floor. Each hole goes in the gap between two joists, never through one, and both are made good afterwards.
Every prop then has to land on something that can carry it. Its base plate is a small area under a real load, so it stands on a sole plate, a timber laid along the row of props, which spreads the load over an area the floor can take. It never stands straight on the floor finish.
The ground floor in this model reads as solid: where the first floor shows a comb of joist ends, the ground floor at the same scale shows a continuous deck with no void under it. A sound solid floor can often take props on sole plates, if our propping design says it can.
On a suspended timber floor they would have gone down to the ground beneath, or onto a base built for them. We design the propping and check what it stands on, with the beam and everything under it, and draw it: each needle and prop tagged and sized by calculation, and the order they go in and come out. The builder puts them in to that drawing and keeps them tight until the beam is working.
We check every temporary works design before it is issued. We can also act as the temporary works coordinator on site, and check the props before the wall comes out.
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The wall comes out
Now the wall below can go, the whole of it, from the underside of the floor down to the ground floor. Until the beam is working, the house stands on the props. Follow the lime line: down the wall above, into the needle, out to a prop on each side, down through the first floor and onto the sole plates.
Nothing about the load has changed. Only its route has. That is the idea behind every beam, every post and every prop in the building: the weight is a fact, and the only question is what carries it and where it lands.
This is the part of the job with the least margin in it, and the part that decides how long the room is unusable, because the props stay until the beam is in and working.
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The beam goes in flush, inside the floor
The beam replaces the wall, so it runs the way the wall ran: away from you, into the page. In this cut you are looking at the end of it, which is why it is drawn as its section, a solid I, rather than a line across the picture.
It goes in flush. The steel sits within the depth of the floor, in among the joists that run the same way it does, instead of hanging below the ceiling as a downstand. Look at where the I sits: it is level with the joist ends, not below them. The ceiling then runs straight through the opening with nothing dropping out of it.
Its ends land where the ends of the wall landed. A pocket is cut at each one and a padstone is built into the top of the pier, flush with it, because its job is to pass load straight down the pier rather than to hang off it. A beam end pushes a lot of load through a small patch of masonry, and the padstone spreads it over enough brickwork to take it.
Three things size the beam: how far it spans, how much it carries, and how far it is allowed to sag. The last one surprises people. A beam strong enough to be perfectly safe can still move enough to crack the ceiling and stick the doors, so the limit on deflection, rather than strength, often decides the section. A flush beam has only the depth of the floor to work within, which is one of the things that decides whether an opening can be flush at all.
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The needles and props come out, and the load transfers
The needle and the props come out last, once the beam is seated on both padstones and packed tight to the masonry above, and the packing has had the time our drawing sets to take load. Until that moment the beam is in the floor but not yet working. The props are eased down evenly and the needle drawn out, then the needle hole in the wall above is filled, and the two holes cut through the first floor are made good.
Watch where the weight goes now. Down the wall above, into the beam sitting in the floor, then along the beam away from you, to a bearing at each end.
The wall used to hand its load to the ground along its whole length. The same load now arrives at two points instead, and everything below each bearing has to be able to take what is handed to it.
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The finished room, and when to call us
From the sofa it is a flat unbroken ceiling and a wider opening, with no beam to look at, because the beam is inside the floor. Structurally it is a beam, two bearings, two piers and two foundations, and all of that was settled before anybody ordered steel.
Call before the beam is ordered, and if you can, before the opening is fixed. The span drives the size, the size drives the weight, and the weight is what you pay for. A slightly narrower opening, or a post you were going to have anyway, can change the answer completely.
The first thing we establish is which way the joists run, because that decides what the wall is holding and so everything that follows it. Photographs of the ceiling, of both sides of the wall, and of the floor above are usually enough to tell us.
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Lime is the load path, the new work and whatever the drawing points at: the joist ends, the beam and the ring round the wall. Anything running away from you, into the cut, is marked in lime: a circle and a cross for the joists and the wall, a solid I for the steel beam, seen end on within the floor. A dashed white outline is what is being taken out, and the dark panel behind it is where it has gone. Plain white is our temporary works design: the needle, the props and the sole plates under their feet. The dark rectangles are the holes cut to let them through.
The ends of the beam are the hard part
Most of the conversation about taking a wall out is about the beam. Most of the risk is at its ends, where the load the wall spread along its length now arrives at two points.
The diagram below is the same opening turned through a right angle. On the model above you saw the beam end on; here you see it from the side, with both bearings in view. A bearing works the same way whether the beam sits below the ceiling or inside the floor, and the same way again over the opening into a rear extension.
The design runs downwards from each one: the padstone, then the pier of brickwork below it, then the foundation under that, then the ground. In an older house the pier is often narrower than you would like and the foundation shallower than you would guess, which is why we ask what is under the floor before we size anything above it.
Diagram drawn for this demo. Not to scale, and not a design.
Key to the drawings
- Existing masonry A flat tone: everything already there, cut or seen.
- Concrete Aggregate triangles and fine dots, scattered at random: foundations, slabs, padstones, lean-mix cavity fill, encasement.
- Undisturbed ground Basket weave, as a band that follows the ground line and fades out.
- Load path Where the load goes, from the roof to the ground; dashed where it runs beyond the cut.
- Load marks Arrows at the symbol weight: loads down onto a member, bearing up under a foundation.
- Hidden, beyond or removed Out of the cut, beyond it, or taken out.
- Cloud Confirm on site. Never a revision mark.
- Break line The drawing stops; the building does not.
Do I need a party wall notice?
Usually not, for a wall in the middle of your own house. The Party Wall etc. Act 1996 starts to matter when the wall you are working on is shared with a neighbour, when you are cutting into that shared wall to seat a beam, or when a new foundation close by goes deeper than theirs. Our standards page covers it too.
Work to a party structure needs notice at least two months before the work. Excavation below a neighbour's foundations within 3 m, or through a 45° line down from them within 6 m, at least one month. Both are minimums, and both run from the notice, so find out early whether either applies. We do party wall surveys.
Source: Party Wall etc. Act 1996.
Do I need Building Regulations approval to take a wall out?
Yes, if the wall carries load. The Building Regulations 2010 treat an alteration as material if at any stage it would leave the building short of Part A, the structure requirement, and a material alteration is building work, which Building Control has to see.
Source: The Building Regulations 2010 (England and Wales), regulation 3.
For a wall removal what Building Control receives is small and specific: calculations for the beam and its bearings; a drawing of where the beam sits, what it bears on and what the padstones are; a note on the foundations if the new point loads call for one; whether the house is still braced; and how the steel is protected from fire, usually by boxing it in with fire-rated board or with an intumescent paint. That is what your builder builds from, and it answers the questions when they come.
You are the one holding this. Under the Building Regulations you are the dutyholder for your own project.
A domestic client is any individual who has building work carried out on their home, or the home of a family member.
As the domestic client, you are in control of the project, which means you must: allocate enough time and resource for the building work to comply with building regulations; appoint designers and contractors; co-operate with anyone working on, or in relation to the project.
GOV.UK, “Design and building work: meeting building requirements”. The regime is Part 2A of the Building Regulations 2010, in force from 1 October 2023.
In practice that means appointing people who can produce what Building Control needs, and giving them time to do it properly, before the builder is standing in the room with a bolster.
What we need from you
For a wall removal, six things get us most of the way:
- The existing and proposed floor plans. A dimensioned sketch is fine if that is all you have.
- Which way the floorboards run in the room above, or a photograph of the joists if a ceiling or a loft hatch is open. That is how we read the joist direction.
- Photographs of both sides of the wall, and of the ceiling above it.
- What sits above the wall, if you know: another wall, a bathroom, a water tank, a roof strut.
- Whether the ground floor is solid or suspended timber, if you know. It decides what the props stand on.
- Anything you have about the foundations or the ground under the house.
Converting the loft as well? Our loft note shows why the two are best designed together.
One more thing
Every design we do meets the Building Regulations. Lean means taking the waste out, not the safety.