Facade and cladding structural engineering
A facade carries no floor loads, but it has to hold itself up, resist the wind trying to pull it off the building and move without cracking as the structure and the weather change around it. We design and check facade and cladding support for new build and remedial work across the UK.
Do I need a structural engineer for cladding?
Yes, once the cladding has to resist wind loads and carry itself back to the structure, which is almost always. We size the support system, design the fixings and confirm the load path so the facade stays on the building in the worst wind the site will see. This is separate from, but coordinated with, any fire or facade material assessment.
What holds a facade on the building
A facade is a skin, and the engineering is all about the connection between that skin and the frame behind it. Self weight has to travel through brackets, rails and fixings back to a floor slab or a structural member, and wind has to be resisted in both directions, pushing the cladding onto the building and, more critically, sucking it off at corners, parapets and around openings where the pressures peak. We calculate the wind pressures to BS EN 1991-1-4, allowing for the building height, exposure and the local zones where suction is worst, then size the support system and its fixings for those forces.
The weak point is almost always the fixing, not the panel. A rainscreen rail is only as good as the bracket that ties it back, and that bracket is only as good as the anchor into concrete, blockwork or steel behind it. We design the anchors to the appropriate standard, allow for edge distances and the real strength of the background material, and make sure the load path from panel to rail to bracket to structure is continuous and checked at every step, including the pull-out and shear on each anchor.
Movement, tolerance and thermal effects
Buildings and facades move, and if the design does not allow for it the facade cracks, bows or shears its fixings. The frame deflects under load and shortens over time, cladding expands and contracts through the day and the seasons, and metal panels move far more than the brick or concrete behind them. We build movement joints and slotted or sliding fixings into the design so each material can move independently, and we check that the gaps close and open within the range the sealants and gaskets can handle.
Tolerance is the other half of this. A facade sits on a structure that was built to construction tolerances, not drawing-board precision, so the support system has to adjust in three directions to pick up a slab edge that is not quite where the model said. We specify adjustable brackets with enough range to take up the real deviations, and we set out the fixing zones so the installer has room to work without running out of adjustment at the corners, which is where problems usually surface.
Remedial work and existing facades
A large part of facade engineering now is checking what is already there. Older cladding may have corroded wall ties, failed brick support angles, or fixings that were never designed for the wind loads we now calculate, and the first job is to establish how the facade is actually held on before deciding what to do. We carry out structural appraisals, review any opening-up and testing, and work out whether the existing support can be retained, reinforced or has to be replaced.
Where brickwork is involved we pay particular attention to support angles and wall ties, because a corroded shelf angle or a broken tie can let a panel of masonry move or bulge with no warning at the surface. For remedial schemes we design new restraint, replacement support angles or a full re-support system, and we sequence the work so the facade stays stable while it is being fixed. We work on projects across the UK, providing calculations and drawings remotely and arranging site inspection by region.
What we check.
The points our calculations resolve for a project like this.
- Wind pressure and suction to BS EN 1991-1-4, including peak corner and parapet zones
- Fixing and anchor design into concrete, blockwork or steel backgrounds
- Continuous load path from panel through rail and bracket to structure
- Movement joints and adjustable fixings for thermal and frame movement
- Support angle and wall tie condition on existing masonry facades
- Re-support and restraint design for remedial cladding work
From enquiry to sign-off.
Enquiry
Send drawings or describe the problem. We confirm the scope, the deliverables and a target timescale.
Information
We agree the survey, drawings or data we need and any site access required.
Engineering
Design, calculation or assessment to the relevant Eurocodes and UK National Annex.
Issue
A clear, defensible report or set of calculations, with assumptions and limitations stated.
Common questions
Do I need a structural engineer for cladding?
Yes, once the cladding has to resist wind loads and carry itself back to the structure, which is almost always. We size the support system, design the fixings and confirm the load path so the facade stays on the building in the worst wind the site will see. This is separate from, but coordinated with, any fire or facade material assessment.
What wind loads do you design facades for?
We calculate wind pressures to BS EN 1991-1-4 using the building height, its exposure and the local wind zones, then design for the worst suction, which usually occurs at corners, parapets and around openings. Suction pulling the cladding off the building normally governs the fixings rather than pressure pushing it on.
Can you assess an existing facade that looks unsafe?
Yes. We carry out a structural appraisal, review any opening-up of the construction, and check the real condition of fixings, support angles and wall ties. From that we advise whether the facade can be retained, needs local repair, or requires a re-support scheme, and we design the remedial work.
Do you cover fire safety of the cladding as well?
Our work is the structural support and fixing of the facade. Fire performance of the cladding materials and cavity barriers is a separate discipline, but the two have to align, so we coordinate our support design with the fire and material specification rather than working in isolation.
Related in structural assessments & specialist services.
Tell us what you are building.
Send the drawings or describe the project. We confirm scope, deliverables and a realistic timescale.
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