So, having decided to use metal for your new roof, the question arises as to how much you need. How on earth do you measure a roof to get an accurate figure?

It’s important that you get it right before you order your sheeting. If not, you may find that you under order and must pay for a second delivery. You may also not get the exact colour match on your second order. If you’re unsure, why don’t you get in touch with a Southport roofing company like Delamere and get them to help you.

So, how do we work this out?

If you know anyone who sews clothes you will be able to get some good tips from her! Every tailor has good advice – measure twice and cut once.

Laying out your roof design on a piece of graph paper is the same as a dressmaker laying out the pattern.


Draw to scale a diagram of the area you need roofed. Remember that metal roofing comes in sheets of either 24” or 36”. Added onto this is a 2” overlap, should you need it.

The sheeting can be bought in any length you need as it is normally cut on site before being delivered to you.

Make sure that you add extra length to the edges where there needs to be an overhang.

Make a note of the length you need and then measure the width.

Now divide this up into segments of 24” or 36” sections which will run from the top down to the base edge.

Draw the segments onto your graph paper

Make sure that you measure the other side of the roof. Do not take it for granted that they are both the same. Sometimes old houses shift, and the measurements may differ. Best to be sure about the size.

Overestimate rather than underestimate. This will mean that you always have a good seal on any overlap. If you skimp on this, you may find your roof leaks when it rains.

The distance from the top edge of the roof to the bottom may not always be the same. This is particularly true in older houses. Don’t order the exact same length but rather add a few inches just in case there is a difference in length.

Remember to add some inches at the bottom so that rain runs into the gutter. Also remember to add an extra amount at the top so that the ridge cap overlaps entirely. More is better than too little up there.

So, the actual measurement of your roof should be the maximum length multiplied by the maximum width. This square footage is then divided up into segments measuring either 24” or 36”. This will give you the amount of roofing you need. Ask for it to be cut into the longest length. This way you will not have any slightly short pieces left over.

To sum up

Measure twice to make sure you have the right lengths. Make sure all your measurements are the same as the manufactures uses, so stick to measuring in centimetres if they use metric measurements. Use inches if they measure this way. It will just make it quicker and easier when you order.