Before You Start: Product Specs & Safety
This guide is for trapezoidal box profile sheets with a 32mm profile height and 1,000mtr cover width. Always follow your manufacturer’s specifications and building regulations. Use proper fall and edge protection when working at height.
1. Preparation & Safety
- Install edge protection or scaffolding.
- Wear gloves, safety glasses, and soft-soled footwear.
- Avoid working in wet or windy conditions.
- Tape measure, chalk line, level, square.
- Electric tek screwdriver with suitable driver.
- Sheet cutting tools: hand shears or nibblers (avoid hot swarf damage).
- Sheets (0.5mm for wall cladding, 0.7mm for Roof cladding).
- Primary fixings with EPDM washers.
- Side-lap stitchers.
- Butyl mastic tape.
- Foam fillers and flashings (ridge, verge, eaves).
2. Measuring the Roof
Measure rise over a 1.000mtr run and calculate degrees.
Eaves to ridge, add 50–70 mm overhang.
Divide total width by 1,000mtr to calculate sheet quantity required.
Note flues, rooflights, or valleys.
3. Sheet Lengths & Laps
Use single-length sheets where possible.
For lengths over 8–10 m, use end laps.
Minimum pitch after deflection: 4° with no end laps; 6–10° for lapped sheets.
Apply two beads of mastic at all end laps.
4. Substructure Preparation
Ensure purlins are straight and correctly spaced
(1.000mtr - 1.375mtr for 0.5 mm; and up to 1.800mtr for 0.7 mm).
Install membrane if specified.
Set a straight eaves line with a string.
5. Setting Out
Start from the verge away from prevailing wind.
Chalk a straight line for the first sheet’s edge.
Allow 30–50 mm verge overhang.
6. Installing the First Sheet
Position with correct eaves overhang.
Ensure square to the steel frame.
Tack in place before full fixing.
7. Fixing Pattern
Fix through the trough into every purlin at eaves and ridge.
Alternate trough at intermediate purlins.
Side-lap stitchers every 300–500 mm.
End laps: fix every trough at the lap purlin.
8. Laying Additional Sheets
Apply mastic on the side-lap.
Align and engage fully.
Stitch as you go and maintain alignment.
9. Flashings & Closures
Fit foam fillers on mastic.
Ridge fillers with mastic, overlap ridge flashings by 150–200 mm and seal with gun grade mastic.
Use EPDM pipe flashings.
10. Finishing Touches
Remove all swarf immediately.
Touch up only small cut edges of flashings.
Check fixings, flashings, and overhangs.
11. Maintenance
Annual inspection for fixings, washers, and sealants.
Clear gutters and clean the roof.
Quick Example
| Roof: | 3.800mtr slope, 6.200mtr wide, pitch 10° |
| Sheets: | 7 sheets (6.200mtr ÷ 1.000mtr cover) |
| Lenght: | 3.860mtr (includes overhang) |
| Purlins: | 1.165mtr centres |
| Fixings: | 16 primary + side-lap stitchers (per sheet) |
- Start square and away from the wind.
- Use unbroken mastic beads.
- Don’t overdrive fixings.
- Don’t leave swarf on the roof.