Special conditions for proper installation are required:

Minimum Pitch:          5°
Max Overhang:           3,5 cm
Horizontal overlap:    15 cm
Side overlap:              9,5 cm

Minimum Roof structure:

> 15 ° 46 cm
10° - 15° 37 cm
5° - 10° Full Deck (OSB, Plywood...)


To maximise performance and in areas of heavy snow, installation on decking is recommended.

  • 15 Onduline screws or nails per sheet (eq. 10 / m2) – 65 mm ONDULINE UNIVERSAL SCREW
  • Make sure to fix every corrugation at eaves and horizontal overlaps.



1. Installation can be on either full deck (recommended) or on discontinuous support (every 37 cm). Once the roof is prepared to the recommended spec, start laying the sheets over the guttering with a maximum overhang of 3.5 cm.

Roof Structure - Duro SX 35 - Deck and Purlins


2. The sheets should be laid in the opposite direction to the prevailing winds. Stagger the rows, by starting the second row with a half sheet. To ensure complete waterproofing, align the two overlapping lines.

The sheets should be laid in the opposite direction to the prevailing wind




3. 15 fixings minimum should be used per sheet. The fixing should always go through the top of the corrugation, in the correct order and in between the two overlapping lines. Wait to fix the last corrugation until you overlap it with the verge element or the next sheet.

DURO SX 35 Minimum 15 Fixings


4. The aesthetics and wind uplift protection can be optimised by using the verge element accessory, which is fixed first on the sidewall, then as well on the top of the corrugation.

Roof Structure - Duro SX 35 - Verge


5. Cover the ridge with the standard ridge and fix it on each side of the roof, on top of each corrugation. The direction of the overlap is opposite to the direction of the prevailing winds.

Roof Structure - Duro SX 35 - Ridge


6. ONDULINE DURO SX 35® sheets provide an attractive. long-lasting finish to a wide variety of timber buildings and are the perfect roof sheet alternative to metal sheets

Roof Structure - Duro SX 35 - Corrugated roof sheets