Is My Roof Suitable For Solar Panels?

So you’re thinking about doing your bit to lower carbon emissions by installing solar panels to generate electricity. The next step is to find out if solar panels are a viable option for your home. For the most part, the answer to this question will depend on your roof.

So in this article, we are going to look at how the various roof types can influence your decision to install solar.

Is your roof an ideal fit for solar?

Below we list popular UK roof types and explain the pros and cons of each, helping your to determine if your roof is an ideal fit for solar.

Composite tiles

Composite roof tiles are popular in the UK, especially for modern homes. Composite tiles are made from cellulose or fibreglass which is combined with asphalt to produce a more natural-looking product. This type of roof is extremely cost-effective, provides excellent thermal performance and looks great.

Their excellent strength and fire resistance properties make them a perfect match for solar panel installations.

Pantiles

The good old fashioned roof tile is the most common roof type in the UK. Roof tiles can be made from a variety of materials including terracotta, slate, concrete and clay. This type of roof is extremely strong and provides good protection against the elements. When properly insulated they also provide excellent thermal performance.

Most tiled roofs are suitable for solar panel installations. However, because tiled roofs are ridged, the panels will need to be installed on frames, this in effect will raise the panels above the roof. This can add to the cost of installation when compared to flat, metal or composite roofs.

The cost of the frames is also dependent on the tile material with frames for clay tiles potentially being more expensive than concrete.

Metal roofing

Metal standing seam is a versatile and durable roofing type which is most commonly found on commercial buildings. But it is becoming more popular for contemporary homes as well. This type of roof is constructed using metal panels running vertically up the roof which are connected using standing seams.

This type of roof is incredibly strong and provides excellent thermal performance. This makes them the ideal roofing type for solar panel installations – allowing for easy attachment of solar arrays (thin film or standard), helping to minimise overall installation costs. The only downside to this type of roof is the modern appearance which is not suitable for all homes.

Tar & Gravel

This is a common roofing material for flat or single plane roofs. The roof is constructed from layers of asphalt bonded together with hot tar. The top layer is then coated with a layer of gravel to provide increased weather protection and durability. This type of roof is cost-effective, long-lasting and energy-efficient.

Because they are relatively flat, fire retardant and strong Tar & Gravel roofs are suitable for solar panel installations. For the most part, solar panels can be installed relatively inexpensively on this type of roof. However, if the roof is completely flat, the panels will need to be installed on a frame to orientate them at a 30-40º angle which will add to the overall cost.

Wood

Wooden roof tiles (shingles) are becoming more popular in the UK, especially on flat-pack or Scandinavian style homes. Wood is an excellent roofing material being cost-effective, easy to insulate and environmentally friendly. However, it is not a suitable material for solar panels.

Wooden roof tiles are not designed to support the weight of solar panels. This can cause tiles to split, especially during cold weather. Wood is also more susceptible to fire, which is an ever-present risk with solar panels due to the amount of electrical equipment required. For this reason, solar panels are not recommended for wooden roofs.

However, don’t panic as there is an alternative option for homes with wooden roofs in the form of ground-mounted solar panels.

Read our Ground Mounted Solar Panels Article for more information.

Thatch

Thatch is one of the most environmentally friendly roofing materials. But, much like wood, thatched roofs are not suitable for installing solar PV panels either. The panels themselves reduce the ventilation thatched roofs need to breathe. This would cause the thatch to rot prematurely and invalidate your warranty.

Also, thatch presents a fire risk. While thatched roofs can be fitted with fire retardant slabs to protect the structure of the roof in the event of a fire. These sit under the thatch so provide little protection against fires caused by an overheating inverter. For this reason, solar panels for thatched roofs are not recommended.

Other things to consider

Your roofs construction is not the only factor which influences whether your home is suitable for solar. The following factors will also need to be considered before you invest in solar:

The roof’s age

The age of the roof is a major consideration. Solar panels and their associated equipment are quite heavy. An old roof will therefore not be able to support the weight of the panels and will quickly deteriorate. Solar panels have a lifespan of between 15-20 years. So it makes sense to install them on a roof which has a similar lifespan.

The size of the roof

Your roof’s surface area will determine how many solar panels can be installed. This in turn will dictate how efficient your system will be. A standard three-bedroomed home in the UK requires a system capable of generating 3kW to be efficient. This will need approximately 12 solar panels, which require a clean surface area of 21 m².

The orientation of the roof

Surface area is only part of the story, you also need to ensure the panels are orientated in the right direction. South-facing panels will allow you to generate the most energy. East or west-facing panels are less efficient, but allow you to generate energy across a longer time frame. While north-facing panels are the least efficient.

Ownership of the roof

You should also consider ownership of the roof. If you live in rented accommodation or a communal building. You will need to obtain permission from the landlord or freeholder. Don’t let this discourage you however, in most cases you will receive permission because solar panels can increase the value of the property.

Conclusion

To sum-up, solar panels are a great way of reducing your energy costs and carbon emissions. But you need to consider whether they are the right solution for your home. The first step is to see if your roof construction is suitable. Then you need to ensure there is enough unobstructed surface area to install the panels.

If you have an old roof or a roof made from unsuitable materials, you will need to factor in the cost of replacement when installing the panels. If you don’t have enough surface area or your roof is orientated in the wrong direction then solar panels can still be installed but you will need to think about supplementing roof panels with ground-mounted panels.