How to calculate the roof area?
Two groups of types of roofing
Sheet metal roofing is divided into two groups when it comes to selecting dimensions for a specific roof:
- custom-made sheets;
- modular sheets.
Custom-made sheets, are sheets cut to specific lengths upon request. Sheets have a fixed width. This is one of them trapezoidal sheets, conventional metal roofing tiles i standing seams.
Calculation of the roof area to order must be based on actual measurements of the roof surface. Dimensions based on the design can only be used for a preliminary estimate, because the actual dimensions of the slope often differ from the design. When measuring, it is important that it is done precisely, because once the sheet metal is cut too short, it will not fully cover the slope. However, a sheet that is too long is less of a problem because it can be shortened with additional work by the roofer.
Modular sheets, are sheets of fixed length that are connected thanks to their special features and cover the roof surface.
Calculating the roof area to order can only be done based on the design, because modular metal roofing tiles can be easily purchased individually from the supplier. By precisely calculating the roof area, as in the case of custom-made sheets, you can select quite precisely the number of sheets of modular roofing tiles. This allows you to save time and avoid unnecessary involvement.
Optimization of the roof surface
Choosing custom-made sheet metal covering requires optimizing the selection of sheet lengths depending on the shape of the slope. Only roofers and qualified people at distributors have the knowledge how to do this. The basic and still common optimization method is graph paper. The person performing this activity draws the shape of each surface and draws and adjusts the sheets. They are then counted and entered into the order.
However, a modern and frequently used optimization method is computer-aided roof calculation. For example, a publicly available application RoofingCAD for Bratex products enables comprehensive roof optimization, including processing. Moreover, if necessary, you can adjust the layout and length of individual sheets. RoofingCAD application has a multitude of functions allowing for the best-selected optimization. In addition, the distributor can automatically transfer sheet lengths and processing from optimization to the ordering application and send the order to Bratex.
There is no need for the investor to learn how to use a specialized application. For this purpose, Bratex Dachy Mrzygłód provides a free roof valuation service based on the submitted design or dimensions. Just send the information to the address Valuation@bratex.pl, and the specialist will make a complete valuation of Bratex products in the variants you choose.
Example of calculating sheets
The simplest example is a gable roof. Divide the width of the eaves (dimension after the gutter) by the width of the sheet covering. For example, a roof with an eaves length of 10 meters is divided by the width of the Snap Lock 0,484 m and rounded up. In this case the result is 21 and it is about the necessary sheets. Therefore, as part of the verification, 21 sheets multiplied by a covering width of 0,484 m covers 10,164 meters - more than the width of the roof. The edge sheets must be cut by the contractor.
The length of the sheets results from the length of the rafters, i.e. from the eaves (gutter) to the ridge (top of the roof).