How many roof sheets do I need?

  1. Find out which direction the rain will flow into your gutter.  This will be the length of your roof.
  2. Measure the length and width of your roof from the high point to the gutter, if you have a gable roof and the ridge meets in the centre, you can simply double your first measurements if you’d rather not measure again.  Use a builder’s tape measure, try to be accurate within 10mm.
  3. Divide the roof width by the width of the sheet (for corrugated this is 0.762) and round your result up to the nearest whole number.  Keep your units in metres.  This is the number of sheets needed to cover your roof!  Use the + – buttons to adjust quantity.
  4. The length required (m) must be entered manually, this is the length you measured earlier and the customised length to which the supplier will cut your sheet.


How many screws do I need?

You will need fasteners to fix your roof sheets to your roof structure. Check out these links to find out which fastener is right for your application.

Handy tips: The quantity of sheets ordered should be about 1.312 times larger than the roof width (or length of the gutter) and rounded up to the nearest whole number.

In a skillion roof, the high point is at the edge of the roof.  In a gable roof, there will be a ridge cap with roof sheets diverting water down either side of the high point to the gutters. Simple skillion or ‘shed’ roofs usually require only one length measurement, multiplied by the appropriate quantity. Simple gable roofs without hips will require two length measurements.

Example: You have measured your skillion roof and found the length of your roof (sheet length required) is 3m, and the width of your roof (length of the gutter) is 5m. Divide 5m by 0.762m to get 6.56, round this up to 7 for the number of sheets required (quantity). Order 7 sheets at 3m. You might want to purchase some tin snips to trim your final sheet to the correct width. See our suggested items or go to Store > Accessories > Tools.

Important stuff.

The maximum length you can order is 15m.  Need something a bit longer?  Give us a call!

Please double-check your calculations before ordering. We cannot refund wrongly measured sheet lengths.  If this is your first time ordering, please feel free to fill out a contact form including your measurements, or send an email with a picture of your roof and its measurements to  The more information you provide, the better we can help.

Minimum order charge is >2m.  Full freight charges apply.

Please note there are limitations to roof sheet lengths which determine which profile you can use.  If you’re not too sure, and would like some friendly advice, drop us a line.

Please read our website terms and conditions of use before attempting to build or renovate and observe the relevant safety laws in your area. Roofit Online accepts no liability for damages caused by the implementation of advice given on here or elsewhere on the website.