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A Complete Guide to Accurate Roof Measuring
Accurate roof measurements are essential from the start of any project. Precise measurements not only save time but also provide confidence and reliability, helping your projects to run smoothly.
In this blog, we will explore the most efficient processes for measuring a roof, saving time and cost on your projects
Measuring Different-Pitched Roof Shapes
Before you begin any roofing project, it is important to have an accurate measurement of your roof area. This will allow you to work out every factor, from how many roof tiles you need to project costs and timeframes.
Depending on the type of roof, the shape can cause complexities when it comes to measuring. The more unique the shape, the more challenging it can be to get an accurate measurement, but the more critical it is to get it right to plan the project effectively.
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Generally, calculating your roof area is a quick and easy process once you know how. In fact, for the classic gable roof, you can work out the size of your roof in just two measurements.
Firstly, you need to measure the length of the roof’s ridge from end to end. Then, measure the roof’s slope height (which is the length from the eaves up to the ridge). To calculate your roof area, simply multiply your roof length by your roof slope height and multiply this by two. This should give you the total area of your roof, not accounting for a chimney or other sections of your roof not covered by tiles.
(Roof length x roof slope height) x2 = roof area
If the roof is not of the classic Gable shape, or if it has multiple sections such as hips and valleys, then it is recommended that you split the roof into each section and work out the areas individually.
See example Gable roofs below:
Allow for Extra Tiles to Cover Waste and Unexpected Breakage
When calculating the number of tiles needed for your roof, it’s crucial to factor in extra tiles to cover unforeseen waste. Tiles often need to be cut to fit edges, corners, and navigate obstacles, which can result in breakage or unusable off-cuts.To avoid project delays or mismatched tiles in future repairs, it is recommended to add around 10% extra tiles to your total order. For example, if your calculated roof area requires 1,000 tiles, you should order an additional 100 tiles to account for waste and breakage. For roofs with complex shapes, patterns, or lots of cutting (such as diagonal layouts or multiple valleys and hips), this allowance may be higher.
Why is this important?
- Ensures you have matching tiles available for repairs in the future.
- Reduces the risk of running short during installation, which can delay your project.
- Minimises colour or batch variation if you need to purchase more tiles later.
Discover Methods for the Succsessful Implementation of Roofing Materials
The successful implementation of low-pitch roofing systems demands meticulous attention to detail during installation. Considerations include the suitability of roofing materials, the importance of headlaps and sidelaps, and rainwater runoff efficiency.
Using the Right Measuring Tools
While a traditional tape measure may have once been the go-to method, there are tools available to speed up the process and reduce complexity.
BMI has introduced a digital tool called, an advanced platform for accurately measuring roofs, offering a range of benefits for installers, contractors, merchants and surveyors. PlanMaster saves time and money whilst delivering *accurate and reliable results.
PlanMaster provides complete control over roofing projects by delivering precise roof measurements anytime, anywhere. Powered by the latest aerial technology, it enables *accurate, data-driven decision-making, enhancing project efficiency.
*Roof measurements are guaranteed to be 95% accurate across the whole roof area
Watch below to see how you can use your PlanMaster report:
Discover how best to use the information contained within your PlanMaster digital roof measurement report
How Does PlanMaster Work?
How Does PlanMaster Work?
BMI’s PlanMaster calculates the width and pitch of a roof by analysing high-resolution aerial images. With detailed roof plans readily available, roofing professionals can optimise their time on site, enhance efficiency, and achieve greater project success through digital specification.
BMI’s PlanMaster uses low-flying drone technology equipped with high-resolution cameras. These images are taken to assess roof measurements for distortion-free and true-to-scale imagery.
Once the roof report has been ordered, a detailed PDF report will be delivered within a maximum of 48 hours, providing a breakdown of all roof areas and plans, accurate* and reliable measurements and high-resolution imagery*
*Roof measurements are guaranteed to be 95% accurate across the whole roof area
The Importance of Getting Roof Measurements Right the First Time FAQs
What challenges can arise from inaccurate roof measurements?
Inaccurate measurements can lead to the wrong materials being ordered, delays in projects and increased costs.
What tools can help ensure accurate roof measurements?
Advanced tools like BMI’s PlanMaster use high-resolution imaging to provide accurate* roof measurements. These tools eliminate guesswork and make the process easier and more efficient for both flat and pitched roofs.
*Roof measurements are guaranteed to be 95% accurate across the whole roof area
Not sure where to start? Get Expert Advice for Your Next Project
If you have questions about measuring your roof or calculating the number of tiles you need, our technical support team is available to help. Our team of specialists are ready to guide you through every step, whether you need clarification on measurements, recommendations for tile types, or advice on planning your project.
- Speak to an Expert: Contact our Technical team for personalised assistance.
- Get to know the full BMI offering: Learn from our experts how BMI products and solutions can support you throughout every stage of your project.
- Access Helpful Resources: Explore our detailed guides, FAQs, and practical tips to support the success of your project.