Temporary Works When Removing Loadbearing Walls Under Flats: A Complete Guide

Temporary works are the structural supports installed during construction to carry loads while a permanent loadbearing wall is removed and replaced with a steel beam. They typically include Acrow props, needles, and strongboys. Getting temporary works wrong risks structural collapse, so a structural engineer must design them and a competent contractor must install them before any wall is removed.

Removing a loadbearing wall in a ground floor flat or maisonette might seem like a straightforward renovation project—until you remember that several tonnes of building structure sit directly above. In converted Victorian terraces and purpose-built blocks alike, the walls that divide your living space often carry the weight of every flat above, their contents, and sometimes the roof structure as well. Get the temporary support wrong, and you're not just risking cracks in your ceiling—you're potentially endangering the structural integrity of an entire building and the safety of everyone in it.

As a party wall surveyor, I regularly inspect properties where loadbearing walls are being removed or altered. The difference between professionally managed temporary works and inadequate support is stark—and the consequences of cutting corners can be catastrophic. This guide explains exactly what temporary works are, why they're essential when working under flats, and how the various professionals, regulations, and legal frameworks come together to protect everyone involved.

Understanding Temporary Works in Construction

Temporary works is the construction industry term for any structure or element that's needed during the construction phase but doesn't form part of the permanent building. In the context of removing loadbearing walls, temporary works refers specifically to the support systems that hold up the building while permanent structural alterations are made.

Think of it this way: when you remove a loadbearing wall, you're taking away something that the building is actively using to stand up. Before you can remove that support, you need to provide an alternative—a temporary structure that can safely carry those loads until your new permanent structure (typically a steel beam or frame) is in place and capable of doing the job.

Why Temporary Works Matter

The loads carried by a loadbearing wall in a multi-storey building are substantial. Consider a typical Victorian conversion with three flats above ground level. The loadbearing walls on the ground floor may be supporting:

• Floor dead loads — The weight of floor joists, floorboards, and any screeds or finishes from all floors above
• Floor live loads — People, furniture, appliances, and other contents in every flat above
• Wall loads — The weight of the walls themselves on each storey
• Roof loads — The entire roof structure plus any snow loading
• Point loads — Concentrated loads from structural elements above bearing onto the wall

We're often talking about loads measured in tonnes, not kilograms. These forces don't disappear when you start removing bricks—they need somewhere to go. Without proper temporary support, they'll go wherever they find least resistance, which typically means the building starts to move, crack, or in extreme cases, collapse.

The Specific Risks When Working Under Flats

Removing a loadbearing wall in a single-storey extension or detached bungalow is relatively straightforward—the consequences of failure, while serious, are limited to your own property. When you're working in a flat with other dwellings above, the risk profile changes dramatically.

Multi-Occupancy Considerations

In a building with multiple flats, your construction work directly affects people who have no control over how it's carried out. If temporary works fail, the consequences fall on your neighbours above—potentially while they're at home, asleep, or going about their daily lives. This creates both ethical obligations and legal responsibilities that go far beyond simple property damage.

The potential consequences of inadequate temporary works in multi-occupancy buildings include:

• Structural movement — Even minor settlement can cause cracking throughout the building, affecting every flat
• Permanent distortion — Floors and walls may end up out of level or plumb, with cosmetic and functional implications
• Progressive collapse — In the worst case, failure of temporary works can trigger a chain reaction affecting multiple storeys
• Evacuation requirements — If temporary works are deemed unsafe, the entire building may need to be evacuated

Victorian and Edwardian Conversions

Many London flats are created by converting large Victorian or Edwardian houses. These buildings present particular challenges for temporary works:

Unpredictable load paths: Original Victorian buildings often have complex structural arrangements that aren't immediately obvious. Walls that appear to be simple partitions may actually carry loads from the floor above. Conversely, apparently solid walls may be non-loadbearing but supported by hidden structural elements.

Historic alterations: Over 150+ years, these buildings have typically been modified multiple times, often without documentation. Previous owners may have removed structural elements, added loads, or altered load paths in ways that aren't apparent from visual inspection.

Material variability: Victorian construction used various brick types, mortar compositions, and timber specifications. The structural capacity of these materials can vary significantly, affecting temporary works design.

Condition deterioration: Age, damp, insect attack, and previous alterations may have weakened structural elements. Temporary works design must account for the actual condition of the building, not just its original specification.

Purpose-Built Blocks

Post-war purpose-built flats present different challenges. Many were constructed using system-build methods or unconventional structural forms:

Large panel systems: Some purpose-built blocks use large precast concrete panels as structural elements. Removing or altering these panels requires specialist understanding of how loads transfer through the building.

Loadbearing crosswalls: Many blocks use loadbearing party walls between flats, with external walls acting purely as weathering. Altering these internal walls affects structural stability.

Non-traditional construction: Various post-war construction methods used novel materials or techniques. Some of these have proven problematic over time and require careful assessment before alteration.

Types of Temporary Support Systems

The specific temporary works required for any project depend on the loads involved, the layout of the building, and the working method being used. However, several standard approaches are commonly employed for removing loadbearing walls under flats.

Acrow Props

The adjustable steel prop—commonly called an Acrow prop after a prominent manufacturer—is the workhorse of domestic temporary works. These telescopic steel tubes can be adjusted to different heights and, when properly specified and installed, can support substantial loads.

Acrow props work by transferring load from above, through the prop, to the floor below. Key considerations include:

• Load capacity: Props come in different sizes with different load ratings. Using undersized props is dangerous—always specify props rated for the actual loads involved.
• Floor capacity: The floor receiving the prop load must be capable of supporting it. On upper floors, this may require additional propping to transfer loads down to foundations.
• Base plates: Props should always have proper base plates to distribute load and prevent punching through floors.
• Head plates: A suitable bearing surface must exist at the top of the prop—usually a timber spreader plate or purpose-made head fitting.
• Vertical alignment: Props must be installed truly vertical. Any lean creates additional forces that reduce capacity.

Props are typically used in combination with needles—horizontal members that collect load from the structure above and transfer it to the props.

Needles and Propping Systems

A needle is a horizontal structural member passed through a wall to support the structure above while allowing the wall below to be removed. Needles typically project through the wall on both sides, with props supporting each projecting end.

The needle and prop system allows wall removal to proceed below the needle while maintaining support above. Once the new permanent structure is installed (typically a steel beam), the loads transfer to the new structure and the temporary needles can be removed.

Critical aspects of needle design include:

• Needle sizing: The needle must be strong enough to carry the loads across its span without excessive deflection. Structural calculations determine the required size.
• Needle material: Timber and steel are both used. Steel needles (often steel hollow sections or universal beams) are stronger but heavier; timber is easier to handle but has lower capacity.
• Hole formation: Creating holes through the existing wall for needles requires careful sequencing to avoid premature loss of support.
• Load distribution: Spreader plates or padstones distribute needle loads to avoid crushing the masonry or structure above.
• Prop positioning: Props must be positioned to maintain needle stability and transfer loads effectively to supporting floors or foundations.

Dead Shores

Dead shoring is a more substantial form of temporary support used when larger sections of wall need to be removed or when the loads involved are particularly high. It's called "dead" shoring because the shores carry vertical (dead) loads rather than resisting horizontal movement.

A typical dead shore arrangement consists of:

• Horizontal sole plates — Timber or steel members laid on the floor to distribute load
• Vertical shores — Substantial timber or steel posts supporting needles above
• Needle beams — Heavy horizontal members passing through the wall
• Head plates — Members distributing load from the structure above to the needles
• Cleats and bracing — Elements preventing movement and ensuring stability

Dead shores are often used when removing entire sections of external wall, creating very large openings, or when working on buildings with particularly heavy loads above. The system creates a temporary structural frame that bypasses the section of wall being removed.

Hydraulic Support Systems

For precision work or where fine adjustment is needed, hydraulic props and jacks offer advantages over mechanical systems. Hydraulic systems can be precisely controlled and adjusted under load, which is valuable when dealing with structures that have already experienced movement or settlement.

Hydraulic systems are particularly useful for:

• Load monitoring: Hydraulic systems can incorporate pressure gauges to monitor loads during construction
• Precision adjustment: Fine control allows for gentle load transfer and correction of existing distortion
• Load equalisation: Multiple hydraulic props can be linked to share loads evenly

However, hydraulic systems require more specialist knowledge to operate safely and may not be appropriate for all domestic projects.

Flying Shores

While less common in domestic loadbearing wall removal, flying shores deserve mention. These horizontal struts span between two buildings (or two parts of a building) to provide mutual support. They're occasionally needed when work to one building might affect the stability of an adjacent structure—a situation that sometimes arises in terrace properties.

Sequencing and Methodology: Getting the Order Right

Temporary works aren't just about having the right equipment—they're about using it in the right sequence. The order of operations is critical to safety, and deviation from an agreed methodology can have serious consequences.

The Typical Sequence for Wall Removal

While every project has unique requirements, removing a loadbearing wall under flats typically follows this general sequence:

Step 1: Survey and assessment. A structural engineer surveys the existing building to understand current load paths, structural condition, and the alterations required. This assessment informs both the temporary works design and the permanent structural solution.

Step 2: Temporary works design. Based on the assessment, a suitable temporary support scheme is designed. This design specifies the type, size, and positioning of all temporary structural elements, along with the sequence for installation and removal.

Step 3: Preparation. The work area is prepared, including ensuring floors can support temporary loads, clearing working space, and assembling materials and equipment.

Step 4: Initial temporary support. Before any permanent structure is disturbed, initial temporary support is installed. This might involve installing props under existing floor joists or beams to prevent movement during subsequent work.

Step 5: Needle holes. Holes are formed through the wall to receive needles. These holes are typically formed one at a time, with each needle installed and propped before the next hole is formed. This staged approach maintains support throughout.

Step 6: Needle installation. Needles are inserted through the prepared holes. Spreader plates or padstones are positioned to distribute loads, and props are installed under each needle end.

Step 7: Load transfer. Props are carefully adjusted to take load from the structure above. This transfer must be controlled—over-jacking can damage the structure above, while under-jacking leaves the needles unsupported.

Step 8: Wall removal. With temporary support confirmed adequate, the loadbearing wall can be removed below the needles. Removal typically starts at the centre and works outward, maintaining stability throughout.

Step 9: Permanent structure installation. The permanent structural solution—typically a steel beam or reinforced concrete lintel—is installed. End bearings are formed, the beam is positioned, and bearing pockets are packed solid.

Step 10: Load transfer to permanent structure. Once the permanent structure is in place and mortar or grout has cured sufficiently, loads can transfer from the temporary works to the new beam. This transfer should be gradual and controlled.

Step 11: Temporary works removal. With loads safely transferred to the permanent structure, temporary needles, props, and other elements can be removed. This should follow the designed sequence—not simply "take it all down."

Step 12: Making good. Holes from needle penetrations are made good, and finishes are restored.

Why Sequence Matters

Every step in this sequence exists for a reason. Skip a step or change the order, and you risk either structural failure or, at best, excessive movement that damages finishes and creates long-term problems.

Common sequencing errors include:

• Removing wall before adequate temporary support: This is the most dangerous error—removing loadbearing structure while it's still carrying load
• Forming multiple needle holes simultaneously: Each hole weakens the wall; forming too many at once can cause failure
• Over-jacking props: Excessive jacking force can crack masonry, distort floors, or damage finishes throughout the building
• Premature prop removal: Taking down temporary support before permanent structures have cured or settled can cause movement
• Ignoring curing times: Concrete and mortar need time to gain strength. Loading new structural elements too soon can cause failure

The Role of the Structural Engineer

A structural engineer is essential for any project involving loadbearing wall removal under flats. Their role encompasses both the permanent structural solution and the temporary works required to achieve it safely.

What the Structural Engineer Provides

For a loadbearing wall removal project, the structural engineer typically provides:

Structural assessment: Understanding the existing building's structural form, identifying loadbearing elements, and determining the loads involved. This may require opening up finishes to inspect hidden structure.

Permanent structural design: Designing the new structural arrangement—typically a steel beam or reinforced concrete lintel—including calculations proving it's adequate for the loads involved.

Temporary works specification: Specifying the temporary support required during construction, including prop types and positions, needle sizes, and installation sequence. Note that on some projects the contractor takes responsibility for temporary works design, but the structural engineer should at minimum review the contractor's proposals.

Construction drawings: Detailed drawings showing both temporary and permanent works, enabling the contractor to execute the work correctly.

Building Control submission: Calculations and drawings for Building Control approval, demonstrating compliance with Building Regulations Part A (Structure).

Site inspections: Inspections during construction to verify work matches the design. For structural work, this typically includes checking temporary support before wall removal, inspecting the permanent beam installation, and confirming adequate bearing.

Choosing a Qualified Structural Engineer

The title "structural engineer" isn't protected in the UK, meaning anyone can use it. For loadbearing wall removal under flats—where the safety implications are significant—you should ensure your engineer is:

• Chartered: Membership of the Institution of Structural Engineers (IStructE) with CEng status, or membership of the Institution of Civil Engineers (ICE) with structural engineering experience
• Insured: Professional indemnity insurance covering the work being undertaken
• Experienced: Demonstrable experience with similar projects, particularly in domestic alterations and older buildings

Building Control is more likely to accept calculations from chartered engineers without extensive checking, which can speed up approvals and reduce costs.

Party Wall Act Implications

Removing a loadbearing wall in a flat often, but not always, engages the Party Wall etc. Act 1996. Understanding which provisions apply helps you plan correctly and avoid delays.

Section 2: Work to Party Structures

If the loadbearing wall you're removing forms part of the structure between your flat and another flat (above, below, or adjacent), it's a party structure. Section 2 of the Act covers work to party structures and requires a Party Structure Notice at least two months before work begins.

Even if the wall isn't strictly a "party wall" in the traditional sense (between you and a neighbour on the same level), the ceiling/floor structure between you and the flat above is a party structure. Removing a loadbearing wall affects this structure—even if you don't directly touch it—because you're altering the loads and support it receives.

Common Section 2 triggers when removing loadbearing walls under flats include:

• Cutting into party structures to form needle holes
• Installing new structural elements (beams) that bear onto party structures

Section 6: Adjacent Excavation

If your loadbearing wall removal involves any excavation—for example, lowering floors, creating a basement, or underpinning to provide adequate bearing for new structural elements—Section 6 may also apply. This section covers excavation near adjoining properties and requires a notice at least one month before excavation begins.

Section 6 applies when you're excavating within either:

• 3 metres of an adjoining structure and going below its foundation level, or
• 6 metres of an adjoining structure and meeting a 45-degree line drawn down from the base of its foundations

In multi-storey buildings, this means excavation in a ground floor flat could trigger Section 6 notices to neighbours on the same level as well as Party Structure Notices to those above.

The Party Wall Award

If your neighbours don't consent to your party wall notices (or simply don't respond within 14 days), a dispute is deemed to have arisen. This triggers the appointment of surveyors who will prepare a party wall award—a legal document setting out exactly how the work must proceed.

For loadbearing wall removal under flats, a party wall award typically addresses:

• Permitted works: Exactly what work is allowed and any conditions
• Temporary works requirements: Specification of temporary support systems, often requiring the surveyor to inspect and approve before wall removal proceeds
• Methodology: The sequence of work, particularly relating to temporary support installation and removal
• Access rights: When and how access to adjoining properties is permitted for inspections
• Working hours: Permitted working times to minimise disturbance
• Schedule of condition: A detailed photographic and written record of the adjoining property's condition before work starts
• Security for expenses: Where appropriate, financial security against potential damage claims

Schedule of Condition

The schedule of condition is particularly important when removing loadbearing walls under flats. This detailed record—typically comprising photographs and written descriptions of every room in the adjoining property near the proposed works—establishes the baseline condition before your work begins.

If the adjoining owner claims damage after your work is complete, the schedule of condition provides evidence of what existed before. Did that crack appear after the wall removal, or was it already there? A proper schedule of condition answers this question objectively.

For loadbearing wall removal, the schedule of condition should pay particular attention to:

• Cracks in walls and ceilings, especially near the party structure
• Floor levels and any existing slope or unevenness
• Door and window operation (sticking doors can indicate movement)
• Condition of decorations that might show movement or cracking
• Any existing structural defects or repairs

What Happens When Temporary Works Fail: Real-World Consequences

The importance of proper temporary works becomes starkly apparent when they're not provided. While I won't identify specific addresses, the following scenarios illustrate real consequences of inadequate temporary support.

Case Study: The Missing Props

A contractor undertaking a ground floor rear extension removed a section of loadbearing wall to create an open-plan kitchen-diner. The structural engineer's drawings clearly showed needle positions and propping requirements, but the contractor decided to "save time" by removing more wall than planned before installing all the specified props.

The ceiling above dropped by approximately 15mm before the contractor managed to install emergency propping. The movement was enough to crack every ceiling in the first-floor flat, distort door frames so that doors wouldn't close, and create a visible step in the floor of the upstairs bedroom. The first-floor flat had to be evacuated while remedial works were carried out.

The total cost of remediation—including structural stabilisation, replastering, redecoration, and the leaseholder's alternative accommodation—exceeded £45,000. The contractor's insurance refused to cover the full claim, arguing the methodology deviation constituted negligence. The ensuing legal dispute lasted over two years.

Case Study: Inadequate Bearing

In a Victorian conversion, a builder installed temporary props directly on suspended timber floor joists without adequate spreader plates. As the props took load, the concentrated forces crushed the joist fibres, allowing the props to sink downward. The structure above followed, causing progressive cracking throughout the building.

The floors subsequently required jacking back to level and new timber inserting where the original joists had been damaged. Several neighbours made claims for cracking damage. Total costs exceeded £60,000, plus the cost of the original works that had to be redone.

Case Study: Premature Prop Removal

After installing a new steel beam, a contractor removed all temporary propping on the same day, before the mortar packing around the beam ends had cured. The beam settled as the wet mortar compressed, dropping the wall and structure above by 12mm.

The floor above sagged, cracking the ceiling below and creating an uneven floor surface. Remedial works required re-propping the floor above, carefully jacking it back to level, then properly packing and supporting the beam. The leaseholder of the flat above claimed successfully for disturbance and the cost of relevelling their kitchen units, which had been installed shortly before the incident.

Building Control Requirements

Removing a loadbearing wall requires Building Regulations approval under Part A (Structure). Building Control—whether the local authority building control department or an approved inspector—must be satisfied that the permanent structural solution is adequate and that the temporary works methodology is safe.

What Building Control Wants to See

For loadbearing wall removal under flats, Building Control typically requires:

Structural calculations: Demonstrating that the proposed new structural arrangement (beam, bearings, and foundations) is adequate for the loads involved. These calculations should be prepared by a qualified structural engineer.

Construction drawings: Detailed drawings showing the new structural arrangement, including beam size and specification, bearing details, and construction sequence.

Temporary works information: While Building Control's primary focus is the permanent structure, they'll want to know that temporary works have been properly considered. Some inspectors require temporary works drawings and methodology statements.

Site inspections: Building Control will want to inspect at key stages, typically including excavation for bearings (if applicable), steel beam installation before covering up, and final completion.

The Building Control Inspector's Concerns

Building Control inspectors dealing with loadbearing wall removal focus on several key issues:

• Load path clarity: Does the new arrangement create a clear, adequate path for loads to reach foundations?
• Beam adequacy: Is the specified beam appropriate for the loads and spans involved?
• Bearing adequacy: Are the beam bearings sufficient to support the loads without crushing?
• Fire resistance: Does the new arrangement maintain required fire resistance, particularly important in flats?
• Temporary stability: Is there a credible plan for maintaining structural stability during construction?

The Dangers of Proceeding Without Approval

Some homeowners and builders are tempted to proceed with loadbearing wall removal without Building Regulations approval, either to avoid fees or to speed up the project. This is seriously inadvisable for several reasons:

• Safety: Without professional scrutiny, there's no assurance the structural solution or temporary works are adequate
• Insurance: Building insurance may be invalidated by structural works undertaken without approval
• Sale complications: Future property sales require evidence of Building Regulations compliance; missing certificates create problems
• Enforcement action: The local authority can require removal of unapproved work, regardless of whether it's structurally sound
• Legal liability: If unapproved work causes damage to other properties, the owner's liability exposure is significant

Planning Checklist for Homeowners and Contractors

If you're planning to remove a loadbearing wall in a flat with other flats above, use this checklist to ensure you've covered all the essential requirements:

Before You Start

• Lease check: Review your lease for any restrictions on structural alterations. Many leases require freeholder consent and/or a Licence to Alter
• Structural survey: Engage a qualified structural engineer to assess the existing structure and design the alteration
• Temporary works design: Ensure temporary works are properly designed, not just left to the builder's discretion
• Building Control application: Submit for Building Regulations approval before starting work
• Party wall notices: Serve appropriate notices on all affected neighbours—typically Party Structure Notice (2 months) and Section 6 notice if excavating (1 month)
• Party wall award: If neighbours don't consent, allow time for surveyor appointment and award preparation
• Schedule of condition: Ensure the schedule of condition is completed for all affected properties before work begins
• Contractor selection: Choose a contractor experienced in structural alterations, with appropriate insurance
• Agree methodology: Confirm the contractor understands and will follow the specified temporary works sequence

During Construction

• Follow the design: Don't deviate from structural drawings without engineer approval
• Staged installation: Install temporary support in the specified sequence
• Regular inspection: Monitor temporary works for any signs of distress or movement
• Building Control inspections: Notify Building Control at required stages
• Party wall surveyor access: Allow surveyors to inspect as specified in the award
• Document everything: Photograph key stages of temporary works and permanent installation
• Curing times: Respect specified curing periods before loading new concrete or mortar

After Completion

• Building Control sign-off: Obtain completion certificate confirming Building Regulations compliance
• Final party wall inspection: Arrange final inspection with party wall surveyor
• Damage resolution: If any damage occurred to adjoining properties, agree and complete remedial works
• Documentation: Keep all certificates, structural calculations, and drawings safely—you'll need them when selling
• Insurance notification: Inform your buildings insurer of the completed structural works

Key Takeaways

• Temporary works are safety-critical elements that maintain structural stability while permanent alterations are made. They require proper design by competent engineers, not improvisation on site.
• Removing loadbearing walls under flats carries significant risks to adjoining properties and their occupants. The consequences of failure extend far beyond your own flat.
• Acrow props, needles, and dead shores are common temporary support systems, but specification must match actual loads—undersized temporary works can cause catastrophic failure.
• Sequencing is as important as equipment. The order of operations—installing support, removing wall, installing permanent structure, transferring load, removing temporary works—must be followed precisely.
• The Party Wall Act typically applies when removing loadbearing walls in flats. Serve notices early (2 months for Section 2, 1 month for Section 6) to avoid project delays.
• A proper schedule of condition protects everyone—it establishes baseline condition before work starts and provides objective evidence if damage disputes arise.
• Building Regulations approval is mandatory. Structural calculations by a qualified engineer are essential, not optional.
• The cost of proper temporary works design and competent structural engineering is trivial compared to the cost of remedying failures—or defending legal claims when inadequate work damages adjoining properties.

Getting Professional Support

Removing loadbearing walls under flats requires coordination between multiple professionals: structural engineers for design, experienced contractors for execution, and party wall surveyors to protect the interests of all affected parties.

If you're planning work that involves loadbearing wall removal, or if you've received a party wall notice from a neighbour proposing such work, professional advice is essential. The investment in proper professional input at the outset is far smaller than the cost of remedying problems that arise from inadequate planning or execution.

For guidance on party wall matters relating to structural alterations in flats, contact our team to discuss your specific situation.