TL-5™ Non-Cyclonic

Penetrations will alter the flow of water on a roof. For further information, please refer to sections "Rainfall Intensity" and "Water Carrying Capacity and Rainwater Run-Off". For assistance in design of roofs with penetrations, please seek advice from your local Fielders representative.

Fastener Spacings - Non-Cyclonic

Crest Fastener Location

4 Fasteners per sheet – Internal and end supports.
Roofing should be lapped away from the prevailing weather.

Valley Fastener Location (Wall Only)

4 Fasteners per sheet – Internal and end supports

Table TL FS NC 001

Note:
1. Do not use punches to form fastener holes. AQUABLOK™ System

The maximum recommended support spacings are based on testing in accordance with AS 1562.1:1992, AS 4040.1:1992 and AS 4040.2:1992. 

Roof spans consider both resistance to wind pressure and light roof traffic (traffic arising from incidental maintenance). Wall spans consider resistance to wind pressure only. 

The pressure considered is based on buildings up to 10m high in Region B, Terrain Category 3, Ms=0.85, Mi=1.0, Mt=1.0 with the following assumptions made: ROOFS: Cpi=+0.20, Cpe=-0.90, Kl=2.0 for single + end spans, Kl=1.5 for internal spans. WALLS: Cpi=+0.20, Cpe=-0.65, Kl=2.0 for single spans, Kl=1.5 for internal spans. These spacings may vary by serviceability and strength limit states for particular projects. 

TL-5™ profile is pierce-fixed to timber or steel supports. This means that fastener screws pass through the sheeting. 

You can place screws for TL-5™ cladding through the crests or in the pans. To maximise watertightness, always place roof screws through the crests. 

For walling, you may use either crest or pan-fixing. 

Always drive the screws perpendicular to the sheeting, and in the centre of the corrugation or rib. Don’t place fasteners less than 25mm from the ends of sheets. 

The edge of TL-5^TM cladding with the anti-capillary groove is always the underlap (see figures below). It is generally considered good practice to use fasteners along side-laps however, when cladding is supported as indicated in maximum support spacings, side-lap fasteners are not usually needed for strength. 

End-laps are not usually necessary because TL-5^TM cladding is available in long lengths. If you want end-laps, seek advice from your local Fielders representative on the sequence of laying and the amount of overlap. 

It is usual to allow roof sheets to overlap into gutters by about 50mm. If the roof pitch is less than 25° or extreme weather is expected, the pans of sheets should be turned-down at lower ends, and turned-up at upper ends by about 80°. Refer to section “Flashings, Cappings & Ends of sheets”.

When TL-5™ cladding is laid on slopes of 5° or less, cut back the corner of the under-sheet, at the downhill end of the sheet, to block capillary action. 

For details regarding spring fixing and crank curving of TL-5™ sheets, please see section “Curving of Steel Decks”.

Benefits of T-Lap™

• Low profile system maintains clean, long run roof lines of roofing.
• A simple cost effective way to achieve a long-length roofing design, even when using shorter roof sheets.
• Minimal change to current installation practice means its fast and easy to install.
• Standard pierce-fixed screw fasteners Tested at our NATA-accredited testing facility.
• If installed correctly, will preserve all existing roofing warranties.
• Safe and effective weather resistant seal.
• Allows for thermal movement of long roof runs.
• No special purlin detailing required - saves you time and money.
• Compatible with translucent sheeting.

T-Lap™ system comprised of brackets which are fixed to the ribs with weather strips.

Figure 1

Background on thermal expansion

All metals expand and contract with changes in temperature. Although steel is by far the least affected of all the metals commonly used for roof and wall cladding, the changes in length experienced in very long runs of roofing are significant.

When T-Lap™ is used, the length of each individual sheet is necessarily shorter, thus reducing the impact of thermal movement.

T-Lap™ is an expansion joint/lap joint hybrid

An expansion joint involves overlapping the ends of the upper sheets over the ends of the lower sheets. With the T-Lap™ system, no extra purlin is needed at the joint as is the current practice with expansion joints.

A profiled weather strip provides protection from wind-blown rain and is made from closed cell polyethylene foam. It is sandwiched between the upper and lower sheets to provide a weather resistant barrier from wind driven rainwater. It also provides air flow and ventilation to reduce likelihood of potential trapped condensate or moisture build-up.

The T-Lap™ bracket is Australian-made Next Generation ZINCALUME® Steel and is an assembly of two pieces.(Figure 4) The two pieces are pressed metal components (an upper and lower piece) inter-locked together and the assembled bracket saddles the rib of the roofing profile. The bracket, as an assembly, is placed on the rib of the lower sheet and the lower piece (base) of the bracket is fixed, via a pre-formed hole, through the rib to the support underneath. The rib of the upper sheet is pierce-fixed directly to the upper piece of the bracket. The upper piece of the bracket is free to move longitudinally relative to the lower piece.

T-Lap™ system (section view).

Figure 2

T-Lap™ joint layout and fixing

The following layout will allow normal pierce-fixed screw fastening at the support and still allow thermal movement to occur at the T-Lap™.

The T-Lap™ system should consist of a T-Lap™ bracket at each rib with weather strips, as per Figure 5. The weather strips are secured in place by being sandwiched between the lower portion of the bracket and the lower roofing sheet. The lower portion of the bracket is secured in-place by the standard roofing screws through the pre-formed hole and through the roofing rib to the support underneath.

The upper roofing sheet is placed so that the ribs sit upon the upper portion of the T-Lap™ bracket. The upper sheet is then fixed to the upper portion of the T-Lap™ bracket using two standard walling screws. Refer to Table 1 for fastener requirements.

Testing

The T-Lap™ system has been tested for performance in wind uplift and weather-resistance at Fielders® NATA-accredited materials science testing laboratory. This means you can be confident that T-Lap™ will perform to specification when installed according to our design limitations and installation guidelines

Layout details of T-Lap™ system at support.

Figure 5

T-Lap™ Installation

TL-5™ span considerations

The spans of the roofing at the joint must be kept within the
following limits:

a. The roofing sheets on either side of the T-Lap™ joint are not to exceed the maximum recommended END span of the roofing.
b. The purlin spacing (roofing span) must be of a practical range – typically 900mm or greater.

Weather Strips

These guidelines describe the laying two rows of weather strips, however in most cases only a single row is required. When using a single row of weather strip (primary weather strip) it must be located on the high side of the T-Lap™ brackets. Two rows of weather strips are recommended in translucent sheet installation or where the roof is exposed to a severe combination of very high wind and high rain. The weather strips are interlocked end-to-end in the traditional way to form a continuous row.

Packers

Packers (10mm thick) may be required to achieve a more gradual change in the roof slope and to ensure drainage at the joint. The packer is positioned on the lowest purlin of the upper sheet for roofs at the TRIM-KLIP® joint system (see Figure 9).

Packers would only be required on shallow roof slopes and when the purlin spacing for the end span is close. For roof slopes of 2.5˚ or more with the purlins spacing at a practical range then no packer is required. For roof slopes less than 2.5˚ then a packer is preferred, however if the purlin spacing is 1150mm or less than a packer is recommended.

Component Quantity

The quantity of components required for a run of joint are given in below table

Packer position for gradual roof slope.

Figure 9

Turning-up

Turn-ups are performed on the upper end of the lower sheets at the T-Lap™ joint using the standard turn-up tool in the traditional way. Holding the end of the tool against the end of the sheet, pull the handle until the resulting turn-up is approximately 30˚ from horizontal being careful not to tear the cladding (due to the material spring back the handle may need to be pulled to approximately 45˚ from the vertical.) ( Figure 10). The resulting turn-up is to be a little less than 20mm in height.

Turning-up TL-5™ at the T-Lap™ joint.

Figure 10

Turning-Down

The upper sheet at the T-Lap™ joint requires the pans at the lower end to be lipped (turned down) prior to laying the sheets using the traditional turn-down tool. Push the turn-down tool over the end of the pan as far as it will go, then hold the tool hard against the end of the pan and pull the handle until the lipped edge bottoms out on the underside of the pan, resulting in a nominal 20˚ degrees lip (Figure 11). Be careful not to tear the sheet.

In severe exposure conditions of combined very high wind and high rainfall situations, the rib crests of the upper sheets at the T-Lap™ end, may also need to be turned down. For more information refer to our cyclonic literature.

Turning-down the pans at the T-Lap™ end joint.

Figure 11

T-Lap™ Installation process

The installation of the roofing should generally be in accordance to the instructions given as above, in the Fielders® Roofing and Walling Installation Manual and the TL-5™ brochure. With regard to the installation of the T-Lap™ system the following steps should be followed.

Step 1: Sheet laying sequence

The laying sequence of the sheets (Figure 12) shall consist of the lower sheets of the roofing prior to the upper sheets as per the sequence shown. The number of sheets laid will depend upon the site conditions and installer programme.

Laying sequence for laying roofing for end joint.

Figure 12

Step 2: Fixing of the lower sheets

Fix the lower sheets at all supports (Figure 13) other than at the support where the T-Lap™ is to be located.

The pans on the upper end of the lower sheet are to be turned-up prior to fitting weather strips and the T-Lap™ brackets. The turn-up is best completed after the sheets are laid and fixed into position.

Lay lower sheets of TL-5™

Figure 13

Step 3: Mark position of brackets

Once the required number of lower sheets is installed, mark the position where the T-Lap™ brackets are to be installed. Use a stringline or straight edge to ensure the position of the brackets is aligned.

Mark the centre of each rib.

Step 4: Place weather strips

Weather strips are installed on top of cladding in continuous rows. (Figure 14) The weather strips are placed to the side of the marker line and in-line with the ends of the T-Lap™ brackets, but not protrude past the T-Lap™ brackets. When two rows of weather strips are used then each row must have the join in alternating pans (i.e. the joins are off-set).

Lay weather strips.

Figure 14

Step 5: Install brackets
(Figure 15)

Position the T-Lap™ brackets on the pre-marked ribs as described in Step 3 and fix as detailed in Figures 1, 2 and 5. Prior to fixing the brackets into position, ensure the weather strips are correctly aligned with the ends of the brackets and ensure the weather strips nest well into the rib/pan corners.

Install T-Lap™ brackets.

Figure 15