Speed Deck Roofing for Commercial and Industrial Buildings

Speed Deck is a concealed-fix steel roof profile made by Stramit, and on large, low-pitch commercial and industrial roofs it is one of the profiles we reach for most. Austek has installed it on a 3,200 m² commercial development at Gregory Hills, a 3,000 m² government building at Bossley Park, and a 400 m² industrial re-roof in Silverwater.

Below: what the profile is, where it earns its place, how it compares with corrugated and trapezoidal sheeting, and the questions to settle before tender.

What is Speed Deck?

Speed Deck is a roll-formed steel roof sheet that clips onto brackets fixed to the purlins. No screws pass through the weather surface of the roof, so there are no fastener holes for water to find, and the clips let each sheet expand and contract along its length as the roof heats and cools. It is designed for long sheet runs at low roof pitch, which is why it turns up on warehouses, factories, schools and public buildings.

Stramit’s current version of the profile is Speed Deck Ultra. The figures below are from Stramit’s published data for it.

The roof spans are published for N1 wind classification, Region A, buildings 7m high or less, on steel supports 1.5mm thick or more. Other wind classes and wall applications have their own tables. Design to the manufacturer’s current tables, not this page.

Where Speed Deck suits a commercial or industrial roof

• Large, low-pitch roofs. Long runs from ridge to gutter on a shallow fall are the job the profile was designed for. Corrugated needs more fall to shed water at the same run length.
• Roofs where fastener leaks are the maintenance problem. An old pierce-fixed roof has thousands of screw penetrations, each with a washer that ages. Taking the screws out of the weather surface removes that failure point.
• Roof and facade packages. On two of our three Speed Deck jobs the roof went on alongside a wall cladding system, and the roof-to-wall junction was the detail that mattered most.
• Public and institutional buildings. At Bossley Park the profile was selected for its strength and suitability for public infrastructure.

It is not automatically the right answer. A small roof broken up by plant, penetrations and changes of direction can lose the advantage, because every cut-out needs detailing around the clip system. For a wider view of the decision on commercial roofing and industrial roofing projects, start from the building, not the profile.

Speed Deck, corrugated or trapezoidal?

The three profiles that cover most of Sydney’s commercial and industrial roof area, compared on the points a specifier gets asked about.

For Stramit’s own profiles, its Roof Slope Design Guide (2023) gives minimum pitches of 5 degrees for Corrugated, 3 for Longspan, 2 for Monoclad and 1 for Speed Deck Ultra. Other manufacturers’ profiles have their own tables. For the broader system decision, read our guide to choosing a roofing system for a commercial building.

Three Speed Deck roofs we have installed

Gregory Hills, commercial, 2019. A new Speed Deck roof and wall cladding at Gregory Hills: 3,200 m² of roof and 600 m² of walls in four weeks, with Interlock 305 wall panels and monument wall construction. The hard part was the transition between the Speed Deck roof and the wall panels. Roof and facade were sequenced so neither trade waited on the other.

Bossley Park, government, 2022. A 3,000 m² Speed Deck roof and 1,200 m² of Danpalon wall system on a government building at Bossley Park, delivered in six weeks with monument roof elements. Same lesson: the weather performance of the building came down to the detailing where the roof met the translucent wall system.

Silverwater, industrial, 2018. A Silverwater industrial re-roof to Speed Deck: 400 m², four weeks, full removal of the old roof in a live industrial environment, with safety rails and walkways built into the new roof.

Read those three together and the pattern is clear. Silverwater was a tenth of the Gregory Hills roof area and took the same four weeks, because it was a strip-and-replace over an operating site with safety infrastructure added. Area sets the materials order. Scope and site conditions set the programme.

Specification questions to settle before tender

Every item is something we will ask before we price.

1. Wind region and engineering. Clip type, clip spacing and purlin fixings are set by the site’s wind classification. Confirm who is engineering the roof.
2. Purlin spacing against the span tables. On a re-roof the existing purlins decide what is possible. Check their spacing against Stramit’s span tables for the base metal thickness and wind class, and against the foot traffic limits if the roof will be walked on.
3. Actual pitch at the lowest point. Measure the built pitch, not the drawing. Deflection on an older frame can take a marginal roof below the minimum.
4. Sheet length and delivery. Long runs need a delivery and lifting plan, so confirm the sheet lengths early.
5. Base metal thickness and coating. Chosen for span, foot traffic and the environment. A site near the coast or near industrial emissions needs a coating class to match.
6. Insulation and condensation. Blanket and vapour control specified for what happens inside the building, not as an afterthought.
7. Penetrations and plant. Every penetration through a clip-fixed sheet needs a flashing detail that still lets the sheet move.
8. Skylights. Stramit’s installation procedure shows 4-rib and 5-rib translucent sheeting for the profile. Settle which one, and where, before the sheet order.
9. Access and fall protection. Anchors, walkways and guardrails have to be fixed in a way that suits a clip-fixed profile, and Stramit does not publish an anchor fixing method for it. Settle the fixing with the height safety system’s designer before the roof is ordered. See our height safety systems.
10. Sheet ends. On low-pitch roofs, sheet ends are turned up at the high end and turned down into the gutter to stop water tracking back. Check it is drawn.
11. Warranty conditions. Warranty on Colorbond and Zincalume steel is set by BlueScope, not by Stramit (see Stramit’s warranty page). Read BlueScope’s conditions for the environment and the installation.

Changing an existing roof to Speed Deck

On an existing building the profile change is only possible if the frame allows it. Purlin spacing, pitch and the condition of the purlins themselves decide whether Speed Deck can go straight on or needs structural work first. That is established on a commercial roof inspection before anyone prices sheet.

Frequently asked questions

Is Speed Deck a standing seam roof?

No. Both are concealed-fix, but Speed Deck is a clip-fixed, roll-formed profile with interlocking ribs, while a standing seam roof joins its pans with a raised seam that is snapped or mechanically folded. Our page on standing seam roofing covers that system.

What is the minimum roof pitch for Speed Deck?

Stramit gives 1 degree for many applications of Speed Deck Ultra. Design to the manufacturer’s tables and measure the built pitch on an existing roof.

Can you walk on a Speed Deck roof?

Yes, following Stramit’s Foot Traffic Design Guide: walk in the pans, not on the ribs, except over supports. Where heavy foot traffic is expected, the guide cuts the 0.48 BMT spans to 1400mm internal and 900mm end. Where maintenance access is regular, designated walkways are the answer, as they were at Silverwater.

Can Speed Deck replace corrugated on an existing building?

Often, subject to the existing purlin spacing, the pitch and the condition of the frame. That is checked on site before it is quoted.

Does Speed Deck come in Colorbond colours?

Yes, in Colorbond and in unpainted Zincalume. Not every Colorbond finish is offered on the profile and some are subject to availability, so check the colour before it is specified.

How long does a Speed Deck roof take to install?

It depends on scope more than area. Our three Speed Deck jobs ran four weeks for 400 m² at Silverwater, four weeks for 3,200 m² plus walls at Gregory Hills, and six weeks for 3,000 m² plus walls at Bossley Park.

Specifying Speed Deck on your next roof?

Send us the roof plan, the pitch if you know it, and whether it is a new building or a re-roof over an operating site. We will come back with the questions that matter for your building and a programme that fits it.

Austek has been working on Sydney commercial, industrial and government roofs since 2010. Send us your roof plan or call 0411 922 441.