SR35+ Sinusoidal Roofing Sheet

900mm cover width, 35mm depth – the flexible standard for commercial and industrial roofing

Available in galvanised (Z275) or polyester white (Z150) | Spans 1.2m–2.8m | Class 1 / Class 0 fire rating

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Typical Applications

Agricultural

Livestock sheds, grain storage, polytunnels, open-sided structures

Industrial

Factories, warehouses, workshops, loading canopies

Commercial

Retail canopies, car ports, garden centres, nurseries

Why SR35+?

Proven system: The sinusoidal profile is the industry standard for single-skin roofing. The 35mm depth delivers excellent spanning capability with minimal weight.

Flexibility: 900mm cover width and multiple gauge options mean you specify exactly what your structure needs — no over-engineering, no waste.

Speed: Straightforward fixing every trough, end lap 150mm, intermediate fasteners in alternate troughs. Fast installation, lower labour costs.

Durability: Galvanised or polyester coating options. Z275 galvanising provides 25+ year service in most UK environments. Class 1 / Class 0 fire rating meets building regulations.

Cost-effective: The SR35+ delivers strength-to-weight performance at the right price point for agricultural, industrial and commercial projects.

Technical Features

Profile Dimensions

Cover Width

900mm

Depth

35mm

Pitch (Wave)

150mm

Crown Height

70mm

Valley Height

43mm

Maximum Length

12m

Available Gauges & Coatings

Standard thickness options in S350 high-yield steel

0.7mm

Galvanised Z275: 7.58 kg/m²

Polyester Z150: 7.43 kg/m²

0.9mm

Galvanised Z275: 9.76 kg/m²

Polyester Z150: 9.61 kg/m²

1.2mm

Galvanised Z275: 13.03 kg/m²

Polyester Z150: 12.88 kg/m²

Coatings & Fire Rating

Galvanised Z275: 275g/m² coating, 25+ year service in most UK environments, corrosion protection
Polyester White Z150: 150g/m² coating, aesthetic finish, Class 1 / Class 0 fire rated (upon specification)
Fire Rating: Class 1 standard; Class 0 available (consult design team)

Section Properties

Per metre run. Top = crown, Bot = valley

Gauge	Weight (kg/m²)	Area (mm²)	Top MoC (cm³)	Top MoI (cm⁴)	Bot MoC (cm³)	Bot MoI (cm⁴)
0.7mm	7.58	917	3.42	20.1	2.95	19.7
0.9mm	9.76	1194	4.12	23.2	3.52	21.3
1.2mm	13.03	1611	7.45	35.7	6.60	35.7

Need load tables and deflection calculations?

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Design & Specification

Spanning & Load Capability

Typical span range: 1.2m to 2.8m (dependent on gauge, load and deflection limit)
Deflection limits: Span/200 for permanent loads (strict), Span/90 for combined permanent + variable
Design factor: 1.5 on yield (building regulations compliance)
Bearing: Minimum 60mm on supports (prevent trough crushing)

Fixing & Lap Details

Fixing: Fastener every trough (not every crown). Stainless or galvanised fasteners; sealant washers where required for water management
End lap: 150mm minimum (two trough intervals). Allow for building movement
Intermediate fasteners: Every alternate trough on intermediate supports for multi-span roofs
Side lap: Not essential for single-skin, but recommended in high-wind or high-moisture environments
Side support spacing: Maximum 450mm centre-to-centre on the edges of the roof
Sealant: Polyurethane or silicone – situational. Consult our technical team for your environment

Design note: Always use RMD’s load tables or engage our design service (paid) for bespoke calculations. Building regulations require structural design by a competent engineer.

Installation & Handling

Delivery & Storage

Sheets supplied in flat stacks on timber bearers, wrapped for weather protection
Store on level ground with damp-proof barriers between layers and stack
Maximum stack height 2m to avoid permanent deformation of lower sheets
Do not drag sheets across the stack – lift and separate

On-Site Installation

Preparation: Ensure supporting structure is level, stable and free of protruding bolts or sharp edges
Laying: Start at one eave, lay sheets perpendicular to the ridge. Work upslope, overlapping ends by 150mm
Fastening: Drive fasteners into the trough (crown is not structural in the vertical plane). Use stainless steel fasteners for galvanised sheet, or matching polyester fasteners
Sealant: Apply polyurethane or silicone sealant to end laps if the roof is exposed to wind-driven rain or high moisture
Safety: Do not walk on completed roofing. Provide crawl boards for access. Use harnesses on pitched roofs over 10m²
Finishing: Seal or flash eaves, valleys, and penetrations with appropriate metal work. Allow sheet expansion: do not over-tension fasteners

Installation tip: Experienced installers will complete a typical agricultural roof (600 m²) in 3–5 days. Single-skin roofing is fast and cost-effective when done correctly.

Want to discuss installation for your project?

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Problems SR35+ Solves

Budget Constraints

Single-skin sinusoidal is the lowest-cost, weather-tight solution for agricultural and industrial buildings. No insulation, no vapour barrier — just protection.

Speed to Install

Straightforward fastening pattern and end-lap detail. Experienced roofers complete large areas quickly. Proven system means no design delays.

Span Requirement Mismatch

Three gauges (0.7, 0.9, 1.2mm) cover 1.2m–2.8m spans with consistent load capacity. No need for expensive deep decking or additional beams.

Corrosion in Harsh Environments

Z275 galvanising offers 25+ years service in most UK environments. Polyester option for coastal or high-acid environments.

Building Regulations Fire Rating

Class 1 standard; Class 0 available. Meets Building Regulations without additional fire barriers for most applications.

Maintenance Burden

Galvanised or polyester — no painting required. Annual inspection for debris and sealant condition. 25+ year lifespan with minimal upkeep.

RMD Profiles Services

We don’t just supply sheet. We support your project from specification through handover.

Supply Only

Sheets cut to length, delivered on your schedule. You arrange design and installation.

Supply & Design

Full structural design, layout drawings, specification and load tables. Professional engineer sign-off. Paid service.

Supply & Fix

We deliver, install and complete your roof to Building Regulations standard. Project management from start to finish.

Tool Hire

Portable sheet-cutting equipment, fastening tools and safety kit available for short- or long-term hire.

Safety Netting

Edge protection, fall-arrest systems and temporary supports to keep your site safe during installation.

Technical Support

Phone and email support, on-site technical advice, and problem-solving throughout the life of your roof.

Frequently Asked Questions

What’s the difference between SR35 and SR35+?

SR35+ is the modern specification, equivalent to the BS EN 1993-1-3 standard. It includes updated section properties, modern coating options and design factors. If you’re specifying new roofing, SR35+ is the right choice.

Can I achieve longer spans with SR35+?

Typical spans are 1.2m–2.8m depending on gauge and load. For longer spans, consider deeper profiles (e.g., SR45) or composite systems. Contact us to discuss your specific requirements.

Do I need sealant on end laps?

Sealant is situational. For sheltered, low-moisture environments (e.g., farm machinery sheds), it’s not always necessary. For exposed or high-moisture locations, polyurethane or silicone sealant is recommended. Consult our technical team.

What’s the warranty on galvanised coating?

Z275 galvanising carries a 25+ year durability statement under UK building regulations. This assumes proper installation and maintenance. Coastal or chemically aggressive environments may require polyester coating for extended service life. Ask us for site-specific recommendations.

Can I walk on a completed SR35+ roof?

No. Single-skin roofing is not designed for foot traffic. Use crawl boards for maintenance access. Falls from height are a serious risk – always use harnesses and edge protection when working at height on completed roofing.

How do I calculate the load my roof can take?

Load calculations require span, gauge, support conditions and deflection limits. RMD Profiles can provide load tables as part of our quotation process, or engage our supply and design service for a full structural report tailored to your project. Do not guess – incorrect design can cause failure.

What fasteners should I use?

Stainless steel fasteners with neoprene or EPDM washers are preferred for all applications. Galvanised fasteners can be used with galvanised sheet if stainless is not available. Polyester-coated fasteners match polyester white sheets. Always use fasteners with sealant washers where water ingress is a risk.

Can SR35+ be used on vertical cladding?

SR35+ is designed as roofing (horizontal or pitched). For vertical walls, consider dedicated cladding profiles or composite systems. Contact us to explore alternatives for your project.

What’s the environmental impact?

Steel roofing is recyclable at end-of-life (estimated 50+ years). Galvanised coating extends service life, reducing replacement frequency. Polyester coating adds slight weight but improves durability in harsh environments. Life-cycle assessment data available on request.

Still have questions? Let’s talk.

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