How to Calculate the Cost of Replacing a Roof

Written by jean asta
  • Share
  • Tweet
  • Share
  • Pin
  • Email
How to Calculate the Cost of Replacing a Roof
The pitch of a roof is one factor that helps determine how much it will cost to replace your roof. (Jupiterimages/ Images)

The cost of replacing a roof depends on a multitude of variables. First, the size of your roof will play a large role in the cost of replacement. The slope of your roof, or whether or not it is easy to walk on, is also a factor. The steeper the roof, the more expensive it will be in labour to replace it. You also have to consider variables such as the materials you will use and the area of the country where you live.

Skill level:
Moderately Easy

Things you need

  • Measuring tape
  • Paper
  • Pencil
  • Calculator

Show MoreHide


  1. 1

    Calculate the square footage of the footprint of your home. Measure the length and width of the house, and multiply these numbers to get the area. For example, a house that measures 30 feet wide by 60 feet long has a footprint area of 1,800 square feet.

  2. 2

    Multiply the footprint square footage by 1.5 to estimate the area in square feet of your roof's surface. In our example, 1,800 multiplied by 1.5 is 2,700 square feet of roof area that will need to be replaced.

  3. 3

    Decide whether or not your roof is walkable or not. A roof with a gentle slope that you could walk without a rope or line is walkable. A roof with a steeper slope is not walkable.

  4. 4

    Multiply your roof area figure from Step 2 by 80p for a walkable roof and £1.20 for a nonwalkable roof. In our example, imagine the roof is walkable. The estimate for replacing the roof will be 2,700 multiplied by 80p or £2,281.

Tips and warnings

  • Contact local roofing companies in your area to ask what the average replacement cost is per square foot for walkable and nonwalkable roofs. Use those numbers in Step 4 to get a more accurate estimate.

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.