August 2020

Option 3
For roof slopes between 5-10 degrees (1 in 11 to
1 in 6 gradient), a fully supporting roof deck
should be laid (20mm minimum), with the same
overhang as option 1 and 2. Lay the sheets
(double corrugation side lap) with a 30cm sheet
end lap and 20 nails or screws per sheet.
Step 3: fixing the sheets to purlins
The fixings used to attach sheets to purlins must
be durable and able to withstand the most
extreme weather conditions. We recommend
using Onduline plastic PP monobloc or Safetop
nails, or Onduline Universal screws.
the sidewall, then on the top of the
corrugation. The ridge element has to overlap
the sheet by a minimum of 12cm.
Step 2: laying the sheets
Start laying sheets in runs in the opposite
direction to any prevailing winds (to prevent side
laps facing the wind and water ingress) and over
the gutter line with a max 7cm overhang.
Approximately 20 fixings should be used per
sheet, with every corrugation fixed at eaves,
overlaps and ridges. Every second corrugation
has to be fixed at the intermediate purlins. The
fixing at the intermediate purlins has to be
staggered.
Step 5: roof support
The roof pitch and occasional load (especially
wind and snow) determine the distance between
the battens. The maximum distance in any case
is 45cm.
“Onduline is with
installers every step of
the way to help make
the installation
process as simple and
straightforward as
possible”
The second row has to be started with half a
sheet cut parallel to the corrugations, to misalign
side overlaps. Adjacent runs should overlap each
other by at least 25cm.
Onduline is with installers every step of the way
to help make the installation process as simple
and straightforward as possible. From high
performance and lightweight roofing systems in
a range of colours to suit any application, to
Onduline’s expert technical team on-hand to
support customers, the company offers a range
of market leading products, backed up with a
first class service offering.
For more information or to find your nearest
stockist, use contact details below:
Step 4: verge and ridge elements
To optimise aesthetic appeal as well as
providing waterproofing and wind uplift
resistance, use a verge element. Fix it first into
Contact Onduline
www.onduline.co.uk
@ondulineUK
AUGUST 2020 TC 35