GRP Staircases
A GRP staircase is a corrosion-free, non-conductive stair built from pultruded GRP stringers and gritted treads. At UIS, we design, fabricate and install GRP stairs for plant, roof and external access across the UK.
Stairs that will not rust or conduct.
A GRP staircase is a fixed stair built from pultruded glass-reinforced plastic stringers, gritted GRP treads and GRP handrails, bolted together rather than welded. It does not rust and it does not conduct, which is why it is chosen for plant access, roofs, embankments and wet or coastal sites.
GRP is worth putting on the table when a painted steel stair is weeping rust at every weld, a slip test has failed on an external stair, or you cannot get a crane onto a live or remote site to lift steel in.
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One team from day one
We own the design, the specification, the fabrication and the installation, so the stringers meet the existing plinth on the day and nobody is left pointing at anybody else.
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Bolted, not welded
The stringers, treads and handrails bolt together on site, so there are no hot works on a live site and the flight can usually go in without a crane.
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Steel fabricators first
We recommend GRP only where corrosion, weight, electrical risk or restricted access make steel the wrong material.
GRP staircase specification at a glance.
What a GRP stair is made of, the standards it is designed to, and the choices that set the price.
- Stringers
- Pultruded GRP channels, sized to the flight and the load
- Standard: BS EN 13706; your engineer's load case
- Treads
- Gritted GRP grating treads, or solid treads with contrasting nosings
- Standard: BS 4592; a wet PTV of 36 or more to BS EN 16165
- Geometry
- Pitch, rise and going, clear width, headroom and landings
- Standard: BS EN ISO 14122-3 and BS 5395 for industrial access; Approved Document K where the Building Regulations apply
- Handrails and guarding
- GRP handrails, with guarding at least 900 mm above the pitch line and 1,100 mm on landings
- Standard: BS EN ISO 14122-3 and BS 6180
- Connections
- Bolted to a GRP or steel platform, a plinth or its own base
- Standard: What the stair lands on at the top and the bottom
- Fire
- A Euroclass to BS EN 13501-1 or a BS 476-7 class, certified for the grade supplied
- Standard: The building's fire strategy
Where GRP stairs are used
- Access stairs to plant, tanks, mezzanines and GRP access platforms
- Roof access stairs, and short stairs at level changes along a GRP walkway
- External stairs on embankments and exposed or coastal structures
- Sites where a crane cannot reach, because the parts can be carried in by hand
If the stair itself is sound and only the treads are worn or slippery, GRP stair treads and nosings can be fitted over the existing treads instead.
Where it is used
- GRP for Water and WastewaterGRP walkways over tanks and channels, platforms at valves and penstocks, and ladders into chambers.
- GRP for Food and DrinkGRP step-overs across lines, platforms at tanks and stairs to plant, for daily wash-down.
- Replacing Corroded Steel with GRPRusted steel grating, handrails and stair treads replaced with GRP, often on the existing frame.
- GRP for Main ContractorsAll the GRP on a project, from riser flooring to roof walkways, detailed, made and installed by one subcontractor.
What decides the price
We price each stair from its drawings or a survey. The main drivers are:
- the number of flights and the total rise
- the clear width, and the landings
- the handrail and guarding runs
- what the stair connects to at each end
- the access for getting the parts onto site
Further reading
- GRP anti-slip gratingHow slip resistance is measured, and which PTV to ask for
- GRP handrail loading standardsBS 6180 load classes, the three load cases, post spacing and test data
- GRP vs steelWeight, corrosion, strength and span compared, and where each one wins
- Fire-resistant GRPReaction-to-fire classes, resin grades and smoke
From material steer to installed staircase.
We steer the material choice, then design, fabricate and install the complete staircase.
Consultation and material steer
You tell us the environment, the access and the loadings, and we tell you plainly whether GRP or steel is the right answer for this stair. That advice comes before the quote, not after it.
Site survey and detailed quote
On site, we survey the access and constraints, using a 3D scan and CAD overlay on retrofit work, then quote against your drawings. Quotations on large commercial packages come back within 1 to 2 weeks, itemised, so the number holds when a surveyor sees the slope or the parapet rather than rising once work starts.
Design, detailing and specification
We design the staircase to your structural engineer's loadings, detail it, and specify the correct GRP profiles, treads, nosings and fixings for the environment. Before fabrication, we issue the drawings for your approval.
Fabrication at Rotherham
At our Rotherham workshop, we cut and assemble the pultruded GRP sections into the finished staircase, prefabricated off-site to compress the on-site programme. We supply and specify the GRP; we do not mould it, and we say so.
Installation by our own team
Our own CSCS-carded fitters install the stair, with a SSSTS-qualified supervisor on every job and full method statements. Our teams have installed flooring, handrails and stairs inside a live supermarket at Oban on night shifts, so a stair can go in around your operations, including out of hours where the site cannot stop.
Handover, O&M pack and aftercare
On completion, we hand over the compliance documentation, including the BS EN 16165 pendulum slip values and the fire classification for the grade specified, in the O&M pack. A defect liability period of 12 months runs on all the steelwork, in line with standard JCT terms (unless your contract sets different terms), and we stay on afterwards as your named aftercare contact.
When the stair belongs on GRP.
We put the stair on GRP where corrosion, electrical risk, weight or restricted access make steel the wrong material: it does not corrode in coastal salt or process chemistry, it does not conduct near switchgear, and it weighs roughly a fifth of the steel equivalent. Outside those conditions, steel is usually the better answer, and because we fabricate both we earn the same either way.
Request a quoteGRP stairs and landings.
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Why the whole staircase sits with one team.
We design and fabricate at Rotherham and install with our own team, and we say so when steel is the better stair.
About UIS-
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One team owns the whole staircase
Our team designs the stair, specifies the correct GRP profiles, treads and fixings, cuts and assembles the pultruded sections, and installs the finished staircase with our own fitters. We neither mould the GRP ourselves nor subcontract the site work, so the company that drew it is the company that bolts it up. Keeping the survey, the fabrication and the fit under one roof means a fitment query no longer bounces between a catalogue supplier and a labour-only fitter.
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02
Geometry checked against the access standard
We set the pitch, the rise and going, the clear width, the headroom and the landings against BS EN ISO 14122-3 and BS 5395 for industrial access stairs, and the guarding to at least 900 mm above the pitch line and 1,100 mm on landings. The stair drawing goes to your engineer for sign-off before anything is cut.
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The safety case arrives on paper, with measured slip values
We build GRP stair treads to BS 4592-0:2006+A1:2012, design the staircase geometry to BS 5395, and design the balustrade to BS 6180 for barrier loading. At handover we issue BS EN 16165 pendulum slip-test values with your O&M pack, alongside the fire classification for the grade specified. The slip resistance is measured rather than asserted, so the safety file is auditable from day one.
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Light enough to carry in where a crane cannot reach
Our teams manoeuvre prefabricated GRP staircase components into position by hand on embankments, rooftops and tight-access plant areas, because at roughly a fifth of the weight of steel they rule out a tower crane or a road closure. That is the same reasoning that let us design and install an access stairway into Thermo Fisher Scientific's lab in Horsham, where an embankment ran alongside the building. The lighter sections install faster and with less disruption to the work going on around them.
"I've worked with UIS for several years on some high profile and very complex projects. Their attitude and work ethic are second to none - providing high quality services and products which are delivered safely and on time every time. Overall they are a pleasure to do business with and wouldn't hesitate recommending UIS for any steelwork or metalwork packages."
GRP stair questions.
We do the lot. We design the staircase, specify the profiles, treads and fixings, cut and assemble the GRP sections at Rotherham, and install the finished stair with our own fitters. You deal with one accountable team from the first drawing to the aftercare, rather than a supplier and a separate fitter.
At handover we issue BS EN 16165 pendulum slip-test values for the treads specified on your project, in the O&M pack. That gives your safety file measured, auditable slip data to put in front of an auditor. The treads themselves are built to BS 4592, the industrial flooring and stair-tread standard.
Fire performance depends on the GRP grade specified for your project. We specify a grade to suit the building and its requirement, and we issue the fire classification for that grade in the O&M pack rather than printing a single blanket rating that would not hold across every grade. Tell us the building at consultation and we will match the grade to it.
Yes. Our own teams work to full method statements and have installed flooring, handrails and stairs inside a live supermarket at Oban on night shifts. Because GRP weighs roughly a fifth of what steel does, the components can often be carried into position by hand, which keeps disruption and lifting plant to a minimum on an operational site.
We recommend steel whenever corrosion, electrical risk, weight and restricted access are not the deciding factors. GRP earns its place in corrosive, non-conductive and no-crane situations; for many internal and standard structural stairs, steel is stronger value and the better answer. As steel fabricators and installers, we are happy to point you that way, and our steel access platforms cover it.
For industrial access, the stair geometry follows BS EN ISO 14122-3 and BS 5395, with Approved Document K where the Building Regulations apply. Treads are specified to BS 4592 with slip values to BS EN 16165, and guarding is at least 900 mm above the pitch line and 1,100 mm on landings. We confirm the detail with your engineer before anything is cut.
Yes. We survey the landing points, design the stair to land on the existing structure or on its own base, and fit the stringers, treads and handrails as one package. A GRP stair can be bolted to an existing steel platform as well as a GRP one.
It is priced on the stair rather than from a list: the number of flights and total rise, the width, the landings, the handrail runs, what it connects to, and the access on site. Send us a drawing or a few measurements and we will quote against them.