The engineering behind the glass.
Structural glass has no dedicated Eurocode. That is not a gap to be worked around — it is the reason every assembly we deliver is calculated, specified and installed against a defined set of standards, and why we keep the evidence.
What we design and test against
A plain-English reference. If you are specifying structural glass, these are the documents that will be asked for at tender, at building control and at handover.
Thermally toughened safety glass
The product standard for toughened glass in building, including its characteristic bending strength. The starting point for every structural and overhead assembly.
Heat-soak tested toughened glass
Heat soaking drives out the risk of spontaneous breakage from nickel sulphide inclusions. We specify it as standard on structural work, overhead glazing and walk-on floors — not as an optional extra.
Laminated glass and laminated safety glass
Governs laminated build-ups and post-breakage integrity — the basis of every walk-on floor, glass beam and glass fin. Interlayers are chosen for stiffness and post-breakage behaviour, not cost alone.
Load resistance of glass panes
The calculation route for glass strength and deflection. Every bespoke assembly we deliver is assessed against it, for its own span, loading and support condition.
Pendulum impact classification
Classification of safety glazing by impact performance — relevant wherever glass sits in a critical location, and required evidence for glazed balustrades and doors.
Barriers in and about buildings
Line loads and deflection limits where glass forms a balustrade, screen or guarding element: 0.36 kN/m in private dwellings, 0.74 kN/m where overcrowding is not expected, 3.0 kN/m where crowds gather.
Actions on structures
Part 1-1 imposed floor loads, Part 1-3 snow, Part 1-4 wind. These give the numbers a glass floor or roof is actually designed against before any glass is selected.
Slip resistance (pendulum test)
The test method for walk-on glass surfaces. We specify to a declared wet pendulum test value — typically 36 or above — and can supply the test data.
Windows and doors — product standard
The harmonised standard behind CE and UKCA marking for the window and door systems we install, with declared air, water and wind performance.
Fire resistance of glazed elements
Test methods for fire-resisting screens, doors and non-loadbearing elements. A rating is only valid when the glass, frame, seals and fixings match the tested system exactly.
Non-fragility of roof glazing
The test methods for whether an accessible roof assembly will arrest a fall. Relevant to any glass roof on a walkable or maintenance-accessed surface.
K · B · E · F · L · O · Q
Protection from falling, fire safety, acoustics, ventilation, energy performance, overheating and security — the regulations our detailing has to satisfy, alongside planning and conservation constraints.
Duty-holder and gateway regime
Product evidence, competence and the golden thread now drive procurement on higher-risk buildings. We assemble and retain the documentation as part of our scope.
Enhanced security performance
Relevant to ground-floor sliding and entrance doors on domestic projects, and increasingly requested by insurers and local authorities.
What a glass assembly is actually designed against
These are the parameters that decide the build-up, the span and the price — long before any glass is selected. Indicative values for early-stage discussion; every project is calculated in full.
1.5 kN/m²
Living spaces, kitchens and landings, to BS EN 1991-1-1. The baseline for an internal walk-on glass floor.
3.0 – 5.0 kN/m²
Home gyms, roof terraces, commercial floors and areas expecting larger gatherings. The build-up and span change with it.
2.5 kN/m² and above
External walk-on glass also has to shed water, resist frost and take a higher duty than an internal floor.
0.36 / 0.74 / 3.0 kN/m
To BS 6180 — private dwellings, areas not susceptible to overcrowding, and areas where crowds gather.
Span / 300 or stricter
Tighter than the code minimum, because perceptible bounce is what makes a glass floor feel unsafe, even when it is not.
Span / 200, or 20mm, whichever is less
Deflection governs glass beams and fins more often than stress does, and buckling restraint has to be designed in.
Typically 10+10mm to 12+12mm
Spans of 2.5–6.0m are routine; much longer spans are achievable with stiffer interlayers and intermediate restraint.
25.5mm internal · 33.7–44.4mm external
25.5mm is typically three 8mm toughened plies with two interlayers; external and higher-duty floors step up in thickness and stiffness.
Four-edge support · 20–25mm bearing
On a structurally fixed frame, with neoprene or EPDM setting blocks so no glass ever touches metal directly.
Within 1mm/m
Glass cannot be packed or adjusted after manufacture. Frame levelling has to be right before the panes arrive.
PTV 36 or above, wet
Measured to BS 7976 on the finished surface, in the wettest condition the floor will realistically see.
Around 40 dB · 45 dB+ separating
DnT,w for an internal glass floor; separating floors between dwellings need more, and the build-up is matched to it.
Five stages, with the risk taken out of each one
Design and engineering are carried out by us. Manufacture is by our specialist system and glass partners. Installation is by our own teams.
Consultation and site review
We visit, listen to the brief and test it against the building. You get an honest view of what is achievable, an indicative cost range and a realistic programme before you commit.
Design and engineering
Structural calculations, glass build-ups, fixing details, interfaces and weathering are resolved and issued. This is where a structural glass project is won or lost.
Manufacture by our specialist partners
Your glass and your systems are produced by our manufacturing partners — Vitrocsa, Schüco, Solarlux, Velfac and specialist laminated-glass producers — to our drawings and our specification, with the certification we require.
Installation by our own teams
Our installers handle, set and seal the glass. Cranage, access, permits and protection are planned with the site team beforehand, not improvised on the day.
Aftercare and documentation
Handover includes guarantees, care instructions and the product records for the project file, with aftercare and glass repair available afterwards.
What we put in your hands
Enough information to specify structural glass properly, and enough evidence to defend it afterwards.
Structural calculations
Glass strength, deflection, buckling and fixing calculations to BS EN 16612 and the relevant product standards, issued as part of our scope rather than left to you.
Specification writing
Bespoke specification clauses and product data for your package, so structural glass and minimal-frame systems are described accurately in the tender documents.
System selection
An honest view of which sliding, pivot or façade system suits the opening — including where a slimmer system earns its cost and where it does not.
CPD for practices
RIBA-appropriate CPD sessions covering system selection, glazing performance, fire strategy interfaces and the points where structural glass projects commonly go wrong.
NBS Source
Published product and system information, so our systems can be incorporated directly into an NBS specification.
Building Safety Act records
Product evidence, test certification and installation records collated and issued for the golden thread of the building.
Documented at handover
Documented, not assumed
Product and workmanship guarantees are issued in writing at handover, aligned to the systems actually installed.
Installed as tested
We install to the tested detail, which is what makes a fire rating or a structural performance figure meaningful on a completed building.
Aftercare
Care instructions, inspection advice and glass repair after practical completion, by the same teams who installed the work.
Accredited and approved: FENSA · GGF Member · Constructionline · CAB · SSIP · RIBA CPD Provider · NBS Source · ISO 9001. Certification, insurance details and test evidence are available on request for tender submissions.
Ask us the difficult question early.
Pre-tender technical meetings and CPD sessions are how most of our best projects begin. Bring the drawing, the span and the constraints — we will tell you honestly whether it works.