T14 roofing sheets: dimensions, cover width and support spacing

The number refers to profile height, not the area covered. One T14 version has a 14 mm profile, an overall width of 1157 mm and an effective width of 1120 mm. For that configuration, the recommended maximum length is 6 m with 0.50 mm sheet and 7 m with 0.70 mm sheet. These dimensions describe one version, not every T14 sheet.

TRB 14/1080 covers 1080 mm. Its overall width can be 1117 or 1132 mm, depending on the version, with lengths of 500–7600 mm in this example. Do not order a missing sheet simply by asking for T14. The profile and coated side must match the material already installed.

Consider a simple roof slope measuring 10 m along the eaves. With a cover width of 1.120 m, 10 ÷ 1.120 = 8.93, so nine sheet strips are needed. Together they cover 10.08 m. This is a calculation example; the actual verge detail has not been included.

With 1.080 m cover width, the result is 9.26, requiring ten strips. That extra strip can affect the total more than a small difference in unit price. Determine the ordered length separately: measure down the slope and account for the eaves, ridge and any end laps.

A roof with a valley or dormer needs a cutting plan, not just division by cover width. Establish whether an offcut can be reused on the opposite slope. Profile geometry and laying direction may prevent this, so do not assume every offcut reduces the next order.

There is no safe universal rule of “T14 at 60 cm centres”. Load tables distinguish material thickness, single- or multi-span arrangements and profile orientation. They address two separate requirements: adequate load resistance and acceptable deflection.

Load resistance and deflection must be checked separately. Deflection limits may be L/150 or L/200, where L is the span. Compare resistance with design loads and deflection with the relevant characteristic loads. Check whether the table includes sheet self-weight. A value exceeding the snow load alone does not complete the assessment: the designer must also consider wind and fixings.

One roofing version of T14 permits a minimum pitch of 6°. For that system, end laps are 300 mm at 6–9° and 200 mm above 9°. These figures illustrate how pitch changes the detail; they are not instructions for any arbitrary sheet. Confirm the requirements for the exact version ordered.

A single sheet from eaves to ridge reduces joints on a long slope, but makes transport and handling harder. An excessively long sheet can be permanently deformed during unloading. If the design uses two lengths, their joint needs suitable support. Extra sealant cannot correct a poorly planned lap.

T14 is worth considering for a simple roof with closely spaced supports. A suitable version may also be used as façade cladding. For a larger hall, first calculate an alternative with a deeper profile. A more expensive sheet may allow a different supporting structure, but that benefit must be demonstrated by calculation.

When comparing quotations, obtain the exact designation, nominal thickness, steel grade, coating and pricing unit. Include a roof plan and the existing support spacing. This gives the supplier information for pricing and the designer information for structural checks. Choose the colour after confirming that the material suits the roof.

For an existing garage, also state the condition and material of the supports. A steel rail and a timber batten require different fasteners. Select screw length and drilling capacity for the substrate; profile height alone is insufficient.

Supports should form a level plane. Check the roof diagonals too: misalignment of the first sheet accumulates as laying progresses. Compare the laying direction with the manufacturer’s instructions. Screws, washers and seals must suit the substrate and installation conditions.

Remove cutting swarf from the coating. Remaining particles can rust and stain it. The final inspection should include eaves, ridge and verges: correct batten spacing alone does not make these details durable.

Not on the strength of the name alone. Compare the full cross-section, width and lap edges.

It may, but only after checking the tables for that version against the building loads.