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The tilt angle at which solar panels are placed on a slanted roof significantly impacts efficiency. The table below shows the ideal tilt angle for each direction. It's unlikely that your slanted roof has the exact ideal angle, but don’t worry—solar panels are usually effective on roofs with a tilt between 20 and 60 degrees. An advisor can provide a reliable estimate of the expected yield on your slanted roof.
| East | 13 degrees |
| Southeast | 25 degrees |
| South | 35-36 degrees |
| Southwest | 25 degrees |
| West | 13 degrees |
When solar panels are placed horizontally on a slanted roof, it is called landscape orientation. When placed vertically, it is called portrait orientation. The orientation does not affect the efficiency of the solar panels; the choice depends on the available space on your slanted roof.
Unlike flat roofs, slanted roofs do not require spacing between solar panels to prevent shading. This means that slanted roofs require less surface area to install the same number of panels. However, it is crucial to maintain enough distance from the roof edge to withstand strong wind gusts. A 20 cm gap is usually sufficient. Additionally, some space must be left so that rainwater can flow into the gutter. If the ridge of your slanted roof is fixed with masonry, two rows of tiles should be left clear.
In most cases, slanted roofs have roof tiles. For these, Zonnefabriek prefers using roof hooks from the German brand Schletter. These are screwed directly into the roof's wooden structure, ensuring stability. If the wood beneath the tiles is too thin, a universal adjustable roof hook is used instead, which clamps onto the battens and tiles. To secure the hooks, the tiles are temporarily moved aside. After installation, the installers ensure the tiles are properly placed again. Once the hooks are installed, aluminum mounting profiles are cut to size and attached to the roof hooks. The solar panels are then secured onto the profiles.
If your slanted roof is covered with bitumen, regular roof hooks cannot be used since there are no tiles to slide hooks under. In this case, special bitumen hooks are screwed into the wooden roof structure. The wood must be thick enough to secure the screws properly. The system is then sealed with adhesive to prevent leaks. To ensure complete waterproofing, an extra layer of bitumen is applied over the hook. Our installers provide a reliable mounting system tailored to your roof type.
South-facing roofs are the most suitable for solar panel installation, as they make the best use of direct sunlight. Roofs facing west or east are also suitable. However, roofs facing north typically have poor efficiency due to insufficient direct sunlight. That’s why our advisors always try to find a solution to orient the solar panels towards the south whenever possible.
read more ›Zonnefabriek can install solar panels on both flat and slanted roofs. For flat roofs, we use the Esdec FlatFix mounting system. This system allows solar panels to be installed at different tilt angles to maximize efficiency from the available surface area. For slanted roofs, Zonnefabriek uses the Schletter mounting system, a durable solution that minimizes pressure on your roof tiles.
read more ›Zonnefabriek offers different mounting systems for flat and slanted roofs. Improper installation can damage both the solar panels and the roof, potentially reducing efficiency. That’s why it’s essential to ensure flawless installation.
read more ›Each type has its pros and cons. In general: thin-film solar panels are the cheapest (per panel) and the lightest (in weight) but produce the least energy; monocrystalline solar panels generate the most energy but are also the most expensive; and polycrystalline solar panels fall somewhere in between the other two categories.
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