Free tool

Sandwich panel calculator

Work out how many sandwich panels you need for your roof or façade, how many square metres to order, how many purlins the structure needs, and an estimate of screws and trims. It is a guide to prepare your quote: when you request it, we confirm sizes, thickness and fixings.

What are you covering?

Length of each roof slope (m)Along the slope, from the ridge to the edge.

Roof width (m)Measured along the ridge.

Overhang (m)How far the panel sticks out past the edge.

Panel effective width

Purlin spacing (m)Usually between 1 and 1.5 m, depending on thickness.

Fixings per panel and supportA guide; it depends on wind and location.

—panels

—length of each panel

—m² of panel to order

—m² of surface to cover

—purlins (support lines)

—approximate screws

—approximate trims (linear metres)

Panels are made to measure and most go up to about 16 m long; if your roof slope is longer, two overlapping panels are used. Want a quote with these sizes? Ask for it here or call us on +34 683 442 608.

How the calculator works

Number of panels: width to cover divided by the panel effective width, rounded up, for each slope.
Length of each panel: the slope length plus the overhang. Above about 16 m it is split into two overlapping panels.
Purlins: slope length divided by the spacing, plus one. The right spacing depends on panel thickness and on wind and snow loads.
Screws: panels × purlins × fixings per support. This is an estimate; the real number depends on wind, height and roof zone.
Trims: linear metres of ridge, side and eaves trims. It does not include flashings against walls, chimneys or rooflights.

To fine-tune your measurements, see our guides on sandwich panel sizes, structure and purlin spacing and sandwich panel price per m².

Frequently asked questions

How many sandwich panels do I need for 100 m²?

It depends on the length of each panel. With 1 m effective width, a 6 m panel covers 6 m², so 100 m² needs 17 panels of 6 m. Enter your sizes in the calculator to get the exact number including the overhang.

How big is a sandwich panel?

The usual effective width is 1 m and the length is made to measure. Most panels go up to about 16 m; longer slopes use two overlapping panels.

How many screws does a sandwich panel need?

It is fixed to every purlin, usually with several fixings per support depending on the model and local wind. The calculator gives an estimate; we specify the exact fixings when we prepare your quote.

Already have your measurements?

We prepare a quote with panels, trims and fixings. Request a quote or call us on +34 683 442 608.