Attachment spacing on a pitched roof

Choose the roof covering, the rafter spacing and the roof pitch — the calculator picks the distance between attachments (every N-th rafter), the load per attachment and checks the rail.

Roof coveringRafter spacing, mmRoof pitchPanel sizePanels per rowPanel rows per tableRegionAltitude above sea level, mBuilding height (roof / ridge), m

Attachment spacing600 mm

Attachments on the raftersevery 1th rafter

Panels in the layout20

Attachments per system72

Uplift per attachment1.58 kN

Pressure per attachment1.19 kN

Attachments and rail hold

Open in the designer

How it is calculated

The maximum spacing is limited by the covering and the snow on the panels (snow × shape factor × cos² of the pitch): near the roof edges it is smaller, and with more than 1.5 kPa of snow on the panels it is at most 800 mm. Attachments sit only on rafters, so the spacing is a multiple of the rafter spacing. Uplift: 1.5 × cp × qp × area; pressure: 1.5 × snow + 1.35 × self-weight.

The calculation is preliminary. A qualified engineer must check it before installation. Codes: DBN V.1.2-2:2006 (Ukraine) and the Eurocode; for other countries — snow and wind values from the national annex, entered by hand.