A composite roof is a relatively recent newcomer to the roofing market that combines the best properties of different materials into a single product. Composite roof tiles are typically made from recycled plastic, rubber, stone aggregate, and natural fibres — or alternatively from steel with a stone-chip coated surface. The result is a material that resembles traditional tile or slate in appearance but is significantly lighter. In Finland, composite roofs are becoming more common especially in renovation projects where the old roof structure cannot bear the weight of traditional tiles. The weight of a composite roof tile is only 6–15 kg/m² compared to concrete tile's 40–60 kg/m² — this difference often eliminates the need for reinforcing the load-bearing structure. The composite roofing market offers a wide range of products with different materials and quality levels. The best-known brands are Gerard, Decra, and Metrotile, which manufacture steel-based stone-chip coated roof panels. Polymer-based composite tiles are manufactured by brands such as Brava and DaVinci. When selecting a product, it is important to verify suitability for Finnish conditions.
Types of composite roofs
Composite roofs are broadly divided into two main groups: steel-based stone-chip coated panels and polymer-based composite tiles. Steel-based products are more common and better known in Finland. In these, a galvanised steel sheet is shaped into a tile, shingle, or slate profile and coated with an acrylic-based binder and natural stone chips.
The stone-chip surface gives the roofing a traditional appearance and effectively dampens the sound of rain — the noise level is significantly quieter than a conventional metal roof. The surface layer also protects against UV radiation and mechanical wear.
Polymer-based composite tiles are manufactured from recycled plastic, rubber, and stone aggregate by compression moulding. They imitate the appearance of clay tiles or slate but are lightweight and impact-resistant. These products have a shorter track record in Finnish conditions, so there is less evidence of long-term durability than for steel-based products.
Installation and suitability
The installation of composite roof tiles resembles that of traditional tile or shingle roofing. Products are fixed to roof battens with screws or a locking mechanism according to the manufacturer's instructions. An underlay membrane is always mandatory in Finnish conditions, as with other roof types.
The most significant advantage of a composite roof during installation is its lightness. When re-roofing an old building where the load-bearing structure was dimensioned for, say, felt roofing, a composite roof does not add extra load. This saves significantly on renovation costs, as reinforcement of the roof truss structure is not needed.
A composite roof is suitable for roof pitches from approximately 14 degrees upwards depending on the product. Steel-based stone-chip coated panels are suitable for lower pitches, while polymer composite tiles generally require a steeper pitch. Wind resistance is excellent — most products have been tested to withstand wind speeds over 200 km/h, which clearly exceeds Finnish requirements.
Durability and maintenance
The service life of a composite roof is 30–50 years depending on the manufacturer and product. Steel-based products typically come with a 30–50 year material warranty, reflecting manufacturers' confidence in the product's durability. In practice, the longest-installed steel-based composite roofs in Finland have about 20 years of service experience, and they have performed well.
From a maintenance perspective, a composite roof is hassle-free. The stone-chip surface does not fade in the same way as painted metal sheet, nor does it become mossy as easily as concrete tile. Annual inspection and gutter cleaning are sufficient for normal upkeep.
Possible issues include damage to individual tiles from impacts (for example, falling branches) and loosening of fixings. Replacing individual tiles is easy, as composite tiles are modular. Manufacturers' spare parts services generally work well, provided the product is still in production — this is where the manufacturer's size and stability should be considered.
Price and comparison
The installed price of a composite roof varies from approximately 40–70 €/m² depending on the product and project. It falls in the price range between metal roofing (35–65 €/m²) and tile roofing (50–90 €/m²). In renovation projects, however, the total cost can be significantly lower than tile roofing because reinforcement of the load-bearing structure is not needed.
In lifecycle costs, a composite roof compares well with both metal and tile roofs. Maintenance requirements are low, and the product's long service life reduces roof replacement costs. On the other hand, the resale value and recognition of composite roofs in Finland are still lower than those of traditional materials.
From an environmental perspective, the situation of composite roofs varies by product type. Composite tiles made from recycled plastic utilise waste material, which is an environmental advantage. Steel-based products use recyclable steel. The recyclability of the roof at the end of its lifecycle depends on the material — metal-based products are more easily recyclable than those made from mixed materials.
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Updated: April 2026
