Knock-Through, Engineered Not Improvised
Removing internal and load-bearing walls to open up your rooms — with the steel beam calculated by our in-house structural engineers, supported on engineered padstones and signed off by Building Control. From a single partition to a double through-room, designed and built under one fixed-price contract, with the Party Wall process handled for you.
Control
Wall
Bearing Removal
By Scope
Steel
No Hidden Cost-Plus
Take the Wall Down the Right Way
Joining two rooms into one is one of the most transformative changes you can make to a London house — and one of the most commonly botched. A knock-through looks simple: take out the wall, make good, decorate. But if the wall is load-bearing, what you are really doing is removing part of the structure that holds your house up and replacing it with a steel beam. Get that calculation, that beam and its supports right and you will never think about it again. Get it wrong and the consequences range from cracked ceilings to genuine danger.
This page is for doing it properly: removing internal and load-bearing walls, the knock-through, wall removal and structural alterations, engineered by qualified structural engineers and built by our own trades under one fixed-price contract. Whether you want to open up the whole ground floor or simply join two reception rooms, the structural discipline is the same.
The first question is always the same: is the wall load-bearing? Many builders will tell you on a glance. We do not guess — we survey, check the direction of the joists above and what the wall is carrying, and only then design the support. Where the wall is non-structural, removal is quick and inexpensive. Where it is load-bearing, we install a steel beam (an RSJ, in common parlance) sized to the span and load, supported on calculated padstones, with the structure temporarily propped while it goes in.
Every load-bearing knock-through requires Building Regulations approval, and where a shared wall is involved the Party Wall etc. Act applies. We handle the structural calculations, the steel, the Building Control submission and inspections, and the Party Wall notices — so the only thing you have to decide is whether the beam should be hidden flush or expressed. For the wider capability behind this work, see our structural works service.
Six Kinds of Wall Removal
From a quick partition removal to a full structural reconfiguration, the approach and the engineering differ. These are the six we handle most.
Non-Load-Bearing Removal
A stud or lightweight partition that carries nothing above comes out quickly, with making-good to floor, walls and ceiling and decoration to match. No beam, no Building Control structural approval — the fastest, cheapest way to join two spaces.
Single Load-Bearing Wall
A structural wall removed and replaced with a calculated steel beam on padstones. The standard knock-through between two reception rooms or a kitchen and dining room. Engineered, propped, installed and signed off — the bread and butter of opening up.
Double Knock-Through
Two openings — or a single very wide opening — creating a full through-room from front to back, the classic Victorian terrace transformation. Often uses paired or deeper beams, and careful sequencing to keep the structure supported throughout.
Wall + Chimney Breast
Removing the dividing wall and a chimney breast together to fully open a room. Both are structural, both need their own support and sign-off, and doing them in one programme is tidy and efficient. See our chimney breast removal page for that side in detail.
Structural Pier / Part Opening
Where a full removal is not feasible or desirable, a wide opening retaining a pier or a section of wall — keeping a degree of separation and reducing the beam span. A neat broken-plan solution where the structure or budget favours it.
Full Open-Plan Reconfiguration
Several walls removed together to create a single open-plan ground floor — multiple beams, coordinated services and finishes. The largest version of a knock-through; our open-plan living page covers the layout, kitchen and zoning side.
What a Knock-Through Actually Includes
A load-bearing wall removal is a sequence of carefully ordered structural steps. Every element below is delivered and warranted under one fixed-price agreement.
Load-Bearing Survey
We establish exactly what the wall is doing — checking joist direction, the load path above and the foundation below, lifting a board if needed — so the design is based on fact, not assumption. The single most important step, and the one most often skipped.
Structural Calculations
Our MIStructE engineers size the steel beam to the span and the load it must carry, calculate the padstones it bears on, and check the supporting masonry. Full calculations issued for Building Control and kept on record.
Temporary Propping
Engineered propping and needling installed to carry the structure safely while the wall is removed and the beam is positioned — the part that keeps everyone safe and the house intact during the opening.
Steel Beam Installation
The universal beam (RSJ) lifted in, seated on its padstones, levelled and connected. Detailed to sit flush within the floor zone where the structure allows, or as a clean, boxed downstand where a deeper section is required.
Padstones & Bearings
Pre-cast concrete padstones to calculation spread the beam's load into the supporting walls, with the masonry checked and strengthened where required — the unglamorous detail that stops a beam punching into a wall over time.
Making Good
The new opening squared and finished, the beam encased or detailed, the ceiling and walls re-plastered, and the junction between the two former rooms resolved cleanly — so the join reads as one room, not a patched-up gap.
Services Re-Routing
Radiators, pipework, electrics, switches and sockets sitting on the removed wall are re-planned and re-routed cleanly into the new layout — coordination that stops the finished room being spoiled by an awkward radiator or socket.
Flooring Continuity
Floor levels matched across the two former rooms and the finish run through — whether repairing existing boards or laying new — so there is no awkward threshold or level change where the wall used to be.
Building Control
Full Building Regulations submission for the structural work, with the steel and bearings inspected before they are concealed and a completion certificate issued — the document that protects you and matters at resale.
Party Wall
Where the wall is shared with a neighbour or a beam bears into a party wall, notices served, schedules of condition prepared and the award agreed — all through our sister surveying company, so it is done correctly.
Decoration
A full decoration of the joined space to a single finish, so the two former rooms read as one — not as a wall that used to be there, freshly painted on either side.
Snagging & Aftercare
A two-stage snagging process, a 12-month defects period and a free service visit at six months.
Is Your Wall Load-Bearing?
It is the question that decides everything — the cost, the method and the approvals. Here are the signs we check, and why a proper survey is the only certain answer.
Joist Direction
If the floor joists above run at right angles into the wall, the wall is very likely carrying them. We lift a board above to confirm direction and span — the most reliable single check.
Does It Continue Up?
A wall that lines up with a wall on the floor above, and continues to the roof, is usually structural — it is part of a load path running down through the house to the foundations.
Spine Walls
The central spine wall running front-to-back through a terrace is almost always load-bearing, carrying floor joists on both sides. These are the walls most people most want to remove.
Thickness & Material
Solid masonry walls are more likely to be structural than thin stud partitions — but thickness alone is not proof, which is why a visual guess from a builder is never enough to design on.
What Sits Above
A wall beneath a bath, a water tank, a heavy stud wall or a chimney is likely carrying concentrated load. We trace exactly what bears on the wall before specifying the beam.
Only a Survey Is Certain
Clues point the way, but the only reliable answer is a structural inspection. We survey before we price, so the design and the cost are based on what is actually there.
Eight Stages, From Brief to Handover
Even a single wall removal benefits from a disciplined sequence. Here is how we run it.
Brief & Free Consultation
We look at the wall (or walls) you want gone, discuss how you want the rooms to work, and talk realistic budgets. No charge, no obligation.
Load-Bearing Assessment
A structural survey establishing what each wall carries, the joist direction and the load path — the basis for an honest design and a firm price.
Opening & Beam Detail
The opening designed, the beam detail (flush or downstand) resolved and shown to you, and the impact on services and finishes mapped out before you commit.
Structural Calculations
Beam and padstone calculations produced by our MIStructE engineers, ready for Building Control submission.
Building Control & Party Wall
Building Regulations submission and, where a shared wall is affected, Party Wall notices served and the award agreed.
Propping, Removal & Steel
Temporary propping installed, the wall removed, the beam lifted in and seated, props struck, opening made good. Building Control inspects the steel and bearings.
Making Good & Decoration
Plastering, services re-routing, flooring continuity and decoration to a single finish, then a snagging walk and the completion certificate.
Defects Period & Warranty
A 12-month defects-rectification period under the JCT contract terms and a service visit at six months.
Four Tiers, Honestly Drawn
A knock-through can be a quick opening or a beautifully detailed one. Here is how our four tiers differ.
Where Your Budget Actually Goes
For a representative single load-bearing knock-through, here is the honest breakdown of where every pound is spent.
The Engineering Behind the Opening
A knock-through is structural engineering first and decorating second. Here is what is calculated and installed.
Beam & Supports
- Beam: Universal beam sized to BS EN 1993-1-1 for the span and load — commonly 152–254mm deep on domestic openings, deeper or paired on wide spans
- Padstones: Pre-cast concrete padstones to calculation, spreading the load into the supporting masonry
- Masonry check: The supporting walls assessed and strengthened where the bearing load requires it
- Connections: Bolted splices where a single beam length cannot be carried into the room
Temporary Works
- Propping: Acrow props and strongboys, or needling through the wall onto props, sized to carry the load above
- Sequence: Structure supported continuously — the wall is never removed before the temporary support is proven
- Protection: Floors, stairs and adjacent rooms protected; dust screening to the rest of the house
- Safety: Method statement and risk assessment for the lift and the removal
Approvals
- Building Control: Full Plans submission with structural calculations to LABC or an Approved Inspector
- Inspection: Steel and bearings inspected before concealment; completion certificate issued
- Fire: Beam fire-protected to the required period where exposed or within an escape route
- Party Wall: Notices, schedule of condition and award by RICS surveyor where a shared wall is affected
Making Good
- Encasement: Beam boxed in plasterboard or detailed flush within the floor zone
- Reveals: Opening reveals squared, with shadow-gap or plastered detail to specification
- Floor: Levels matched across the opening and the finish run through cleanly
- Services: Displaced radiators, sockets and switches re-routed and re-sited cleanly
Building Regulations & Party Wall for Wall Removal
A knock-through is almost never a planning matter — but it is always a Building Regulations one if the wall is load-bearing.
Removing an internal wall does not require planning permission in an unlisted house — you are not touching the exterior or the footprint. What it does require, whenever the wall is load-bearing, is Building Regulations approval. The structural design must be calculated, submitted, and the steel and bearings inspected before they are hidden, with a completion certificate issued at the end. That certificate is not red tape — it is what protects you, satisfies your insurer and reassures a future buyer's surveyor.
Where the wall is a party wall — shared with an attached neighbour — or where a new beam will bear into it, the Party Wall etc. Act 1996 applies. Notice must be served on the affected neighbour, a schedule of condition prepared, and an award agreed before work starts. We manage this through our sister surveying company, so it is done correctly rather than discovered too late.
The only time planning enters the picture is if the project also involves a Listed building (where internal alterations need Listed Building Consent) or an extension of the footprint. We confirm exactly what your knock-through needs at survey and manage every approval for you. For an early budget, use the cost calculator; if you are opening up the whole floor, see open-plan living.
A Load-Bearing Knock-Through, Week by Week
A representative programme for a single load-bearing wall removal with a steel beam. Yours will differ by scope, but this is what a properly run knock-through looks like in real time.
What Sets Our Knock-Throughs Apart
Plenty of builders will take a wall out. Here is what makes ours safe, clean and worth the difference.
Engineer In-House
Our own MIStructE engineers calculate the beam — the design and the build sit under one roof, not split between a separate consultant and a builder guessing.
We Survey, We Don't Guess
We confirm whether a wall is load-bearing by inspection before we price — never by a glance, which is how dangerous shortcuts happen.
Single Fixed Price
One agreement covering survey, design, steel, approvals and finishes. No cost-plus surprises once the wall is open.
Clean Beam Details
We design steel to sit flush wherever the structure allows — no clumsy unplanned downstand cutting across the ceiling.
Building Control Handled
Submission, inspection and completion certificate managed for you — the paperwork that protects you at resale.
Party Wall Managed
RICS-regulated chartered surveying for the Party Wall process through our sister practice, Hampstead Chartered Surveyors, where a shared wall is involved.
£5M public liability, £10M employers' liability and contractors' all risks cover
Certificates are available on request.
12-Month Defects Period
A defects period covering the structural work long after completion.
Explore Related Structural & Layout Work
A knock-through often sits within a wider project. Start here, or speak to us about combining it under one contract.
Open-Plan Living
Opening up the whole ground floor — the layout, kitchen and zoning side of multiple knock-throughs.
Chimney Breast Removal
Often done alongside a knock-through — structural removal on gallows brackets or steel.
Structural Works
The full structural capability — beams, openings, underpinning and floor strengthening.
Structural Engineering
The calculations and detailing behind every beam and opening, by MIStructE engineers.
Kitchen Renovation
Joining the kitchen to the living space is a common reason to knock through — designed together.
Side-Return Extensions
Combining a knock-through with a side-return for the widest possible rear space.
House Renovation
Wall removal as part of a wider whole-house renovation, delivered as one programme.
Party Wall Services
The notices and awards required where a knock-through affects a shared wall.
Wall Removal & Structural Proof
Comparable projects with real structural openings and finishing standards. Browse the case-study hub, and for survey-led due diligence before you commit, see surveying support.
Open-Plan Living, West Hampstead NW6
Load-bearing walls removed on engineered steel to create a single open-plan ground floor.
View case study →Rear Extension & Kitchen, Primrose Hill
Structural opening and rear extension joining the kitchen to the living space.
View case study →Victorian Townhouse, Maida Vale W9
Structural reconfiguration and multiple openings within a full townhouse renovation.
View case study →More Completed Projects
Browse the full portfolio of openings, extensions and renovations across prime London.
View portfolio →Detailed Answers to the Questions That Matter
What is a knock-through?
How do I know if a wall is load-bearing?
How much does it cost to remove a wall or knock through in London?
Do I need planning permission to knock through a wall?
How long does a knock-through take?
What is an RSJ, and how big will the beam be?
Will I be left with a downstand beam, or can it be hidden flush?
Do I need a structural engineer and Building Control for a knock-through?
Is a party wall agreement needed for a knock-through?
Can you remove a chimney breast at the same time as a knock-through?
What Our Clients Say
“I would like to thank Ross and his team for their consistent commitment to quality and their unerring reliability. They delivered our property to specification and on time, proving to be an extremely effective, experienced, and proactive contractor.”
“We have worked with Ross and his company many times. They are extremely professional and hardworking individuals who can work under any circumstances. There was no variation to the works.”
Plan Your Knock-Through
Book a no-obligation consultation at our Finchley Road design studio or in your home. The first meeting is free, lasts 60–90 minutes, and concludes with an honest indication of feasibility, programme and budget band. No salespeople. No pressure.
Free Wall-Removal Consultation
Site visit · feasibility assessment · outline cost estimate · programme indication. No obligation. Saturday appointments available.
Completed renovation project examples
