Trapezoidal Sheet Metal for a Garage: Which Profile Should You Choose?
Trapezoidal sheet metal is a popular roofing solution for garages, carports, workshops and other smaller buildings. It is lightweight, affordable, quick to install and, when the right profile is selected, can provide reliable protection for many years.
When choosing trapezoidal roofing sheets, price and colour are not the only factors to consider. The most important parameters are the profile height, sheet thickness, roof pitch and spacing of the supporting structure.
T8 and T12 – Better for Cladding and Lightweight Structures
The number in the product designation generally indicates the height of the profile. T8 therefore has a profile height of approximately 8 mm, while T12 has a height of approximately 12 mm. As a general rule, a higher profile provides greater rigidity.
T8 and T12 are economical solutions particularly suitable for fences, wall cladding, soffits and lightweight structures.
At Roofer.cz, T8 Glossy currently starts from approximately CZK 193/m² incl. VAT, while T12 Glossy starts from approximately CZK 195/m² incl. VAT.
For a standard garage roof, however, we would usually recommend choosing a higher profile.
T18 – A Versatile Choice for a Standard Garage
For a typical detached garage or carport, T18 is one of the most practical options. It offers a good balance between strength, weight and price.
T18 Glossy at Roofer.cz currently starts from approximately CZK 197/m² incl. VAT for a 0.40 mm sheet. The 0.45 mm version costs approximately CZK 217/m², while the 0.50 mm version costs approximately CZK 233/m² incl. VAT.
For a standard garage roof, we generally recommend considering a thickness of 0.45–0.50 mm, depending on the design of the supporting structure.
For example, 40 m² of T18 Glossy in 0.50 mm thickness costs approximately CZK 9,320 incl. VAT for the roofing sheets themselves. The savings achieved by choosing the thinnest sheet are relatively small, so it is usually better not to select roofing material based on the lowest price
T35 – For Larger Garages and Higher Loads
For larger garages, double garages, workshops or structures with greater spacing between supports, T35 can be a better choice.
Its 35 mm profile provides greater rigidity, while the difference in material price compared with T18 can be surprisingly small.
For example, T35 Glossy in 0.50 mm thickness costs approximately CZK 242/m² incl. VAT at Roofer.cz, while T18 in the same thickness costs approximately CZK 233/m².
The difference is therefore only around CZK 9/m².
For this reason, the profile should primarily be selected according to the roof structure and expected loads rather than simply according to the price per square metre.
Watch Out for Condensation
Condensation can occur on the underside of sheet metal roofing, particularly in uninsulated garages. Water droplets can then fall onto the vehicle, tools or garage floor.
One solution is the DRIPSTOP anti-condensation layer, which absorbs condensation and allows the moisture to evaporate again when ventilation conditions are suitable.
For selected trapezoidal profiles at Roofer.cz, DRIPSTOP is available for an additional cost of approximately CZK 65/m² incl. VAT.
For an unheated garage or carport, this can be a practical investment that helps prevent problems with dripping condensation.
Which Surface Finish Should You Choose?
Galvanised sheet metal is usually the most economical option. For example, T18 Galvanised 0.40 mm currently starts from approximately CZK 166/m² incl. VAT.
For garages located next to residential properties, coloured polyester-coated sheets are often preferred. T18 Glossy starts from approximately CZK 197/m², while T18 Matt starts from approximately CZK 213/m² incl. VAT.
Matt finishes are particularly popular for modern buildings, where the garage roof can be matched with windows, gutters, façade elements or fencing.
So, Which Trapezoidal Sheet Should You Choose?
For most standard private garages, we consider T18 in a thickness of 0.45–0.
50 mm to be an excellent solution. It provides a very good balance between price, rigidity and appearance.
For a larger double garage, workshop or structure with wider support spacing, T35 is worth considering, especially because the price difference compared with T18 can be relatively small.
T8 and T12, on the other hand, are generally better suited to cladding and lightweight structures.
The final profile and sheet thickness should always be selected according to the dimensions, roof pitch and supporting structure of the particular building.
