Metal tiles: how to calculate and choose a material for the roof

Recommendation points

• The choice of metal tiles by type and thickness of metal
• Selection by type of metal covering of metal tiles
• How to calculate the required number of sheets
• Our opinion

Metal tiles are the best option for roofing, they are easy to use and relatively inexpensive. It should be chosen based on two main parameters – metal and its coating. Let’s talk about how to choose a metal tile and correctly calculate the amount of material.

The choice of metal tiles by type and thickness of metal

Metal tiles can be made from steel, galvanized steel, aluminum and copper. Tiles made of aluminum and copper are quite an expensive option and we will not consider them here. Steel can be black or galvanized. The most responsible manufacturers of metal tiles always apply a zinc layer to the metal sheet, the quality of the tiles depends on its thickness. We will not give recommendations on choosing a manufacturer, just when purchasing a metal tile, pay attention to the amount of zinc on the tile, for this ask the seller for a quality certificate. When choosing, we often have to pay attention not only to the quality of the material, but also to the price. Be careful, some manufacturers, in order to reduce the cost of their products, go for the fact that they use a sheet of black steel for the manufacture of metal tiles, without galvanizing. We strongly advise against purchasing such shingles. If the budget does not allow you to purchase galvanized, it is better to consider replacing the metal tile with a cheaper roofing.

Steel for the production of metal tiles is used with a thickness of 0.4–0.6 mm. Of course, the thicker the better. However, for roofs with a slope of more than 20 degrees, a thickness of 0.45 mm is also quite suitable, subject to the manufacturer’s recommendations for the implementation of the lathing. Metal tiles with a thickness of 0.4 mm can be used on roofs with a slope close to 45 degrees, on which you will not have to walk in the future. Sometimes the manufacturer or seller indicates the thickness of the coated metal tile. Don’t let that fool you. Check exactly the thickness of the metal, that is, the thickness of the galvanized sheet. On roof slopes less than 20 degrees, metal shingles with a thickness of less than 0.5 mm should not be used.

So: galvanized steel with a thickness of 0.45 mm.

Selection by type of metal covering of metal tiles

In addition to galvanizing, metal tiles are covered with a protective and decorative layer, this is the coating. Most often found: polyester, plastisol, pural (PURAL). The most affordable is polyester coating, its main disadvantage is less resistance to mechanical damage. But if you decide to do the work yourself, be careful and accurate, and such a coating will serve you no less than others. Polyester with special additives and a slightly different method of applying the coating itself, which makes it possible to increase its mechanical resistance, is called pural.

This type of coating will probably be the most optimal in the combination of price-quality properties. Plastisol coating is more progressive. It, as a rule, has a greater thickness and has improved quality characteristics. In addition, most types of plastisol coatings have a characteristic surface roughness, which, according to most, makes such a metal tile even more attractive in terms of roof design. However, such coverage is more expensive. Please note that tiles such as Viking are not plastisol. A special complex of polymers is used here, which in its characteristics is nevertheless closer to polyester than to plastisol. The coating has a slightly thicker and slightly better resistance to mechanical damage, at a cost comparable to polyester.

It’s up to you, but probably PURAL.

Glossy or matte, and which profile: monterrey, supermonterrey, cascade and many others, it’s up to you.

How to calculate the required number of sheets

Usually sellers of metal tiles insist that they measure the required number of sheets. Sometimes additional fees apply. It is not so difficult to count sheets of metal tiles. If the roof is single-pitched or gable with gables, then each slope is represented as a rectangle of a certain size. The tiles in the sheets are also rectangular. Everyone can calculate how many smaller rectangles will fit into a larger rectangle. The overlap of one sheet on another is not difficult to take into account, knowing this value for different types of metal tile profile (it is easy to look at the technical characteristics).

If the roof has valleys or is hip, then it is a little more difficult. Select a regular rectangle on the roof and adjacent triangles. With a rectangle, everything is the same as on a pitched roof. We do this on the triangle. We take the width of a sheet of metal tile, measure this value from the adjacent rectangle, taking into account the overlap. We measure the length of the sheet so that it completely covers our triangle in height, part of the sheet of metal will be superfluous, this will be the length of the sheet. We measure another width of the sheet, now from the previous one, the first in the triangle. We measure the length of the sheet again, until the moment when it completely covers the triangle. Etc. Move to the next triangle.

The length of the sheet of metal, as a rule, must be chosen according to the length of the roof rafters, with an overlap to the drainage gutter. The amount of overlap in different tile profiles is different, you will clearly see this, in fact, the finished roof with rafters and crate. If the length of the rafters is more than 8 m (the largest standard length of a sheet of metal tile), then take an eight-meter sheet and count the additions along the length.

Our opinion

Do not believe that the waste on metal tiles is minimal. This is only true for gable and pitched roofs. Today, in order to make the house more attractive, many people try to make a shape other than a rectangle. Consequently, the roof has a more complex configuration. On complex roofs (even one or two valleys) there is a lot of waste on the metal tile, and this must be borne in mind.

Also, from experience, we can say that little of the waste can be used in business, and you should not count on it. However, despite this, metal tiles are one of the most optimal materials that can be used to cover the roof..