How to Make a Pergola Roof

A pergola can transform a garden into a more usable and attractive space, providing shade, structure, and definition to an outdoor area. While an open top pergola offers a traditional design, many homeowners look for ways to add a roof so the structure can be used more comfortably in the unpredictable British climate. Whether the aim is to create partial shade, provide rain cover, or simply make the pergola look more finished, there are a variety of methods available. Building a pergola roof is not overly complex but it does require careful planning, the right materials, and some knowledge of how to keep the structure safe and durable.

Planning and Permissions

Before adding a roof to a pergola, it is worth checking if planning permission is required. In most cases, a pergola that is under 2.5 metres high and located at the rear of a property will fall under permitted development rights. However, if the pergola is close to a boundary or forms part of a listed property or conservation area, restrictions may apply. It is always wise to contact the local planning department for guidance before carrying out the work. Building regulations are less likely to apply for a small garden structure, but if the pergola is attached to the home or part of a larger extension, additional requirements may be necessary.

Choosing the Right Roofing Option

The type of roof added to a pergola will depend on how the space will be used. A simple slatted roof made from timber battens offers dappled shade without fully blocking out light. For those looking for weather protection, polycarbonate or corrugated plastic sheets provide a lightweight and practical solution. Fabric covers such as canvas or shade sails are popular for creating a softer look and can often be removed during the winter months. A more permanent choice might be metal roofing or even tiles, although these add weight and require the pergola to be reinforced. Each material has its own advantages in terms of durability, cost, and appearance, so the decision should balance practical needs with style preferences.

Materials and Tools Required

Most pergola roofs can be constructed using straightforward materials that are readily available from DIY suppliers. For a slatted roof, treated timber lengths will be required, along with exterior screws and fixings. For plastic or polycarbonate sheeting, the sheets should be cut to size and fixed with the correct roofing screws and washers to prevent leaks. Shade sails or fabric covers need fixing kits with strong brackets and tensioners. Tools usually include a saw, drill, tape measure, spirit level, and ladder. As pergolas are outdoor structures, all fixings should be rust resistant to withstand the elements.

Building a Slatted Pergola Roof

A slatted roof is one of the simplest options to construct. The battens or timber strips are fixed horizontally across the top of the pergola beams, evenly spaced to provide partial coverage. The spacing can be adjusted to allow more or less light through depending on the desired effect. To ensure stability, each batten should be screwed securely into place and treated with a weather resistant finish to prevent rot. This type of roof provides a stylish appearance and works well for climbing plants such as wisteria or clematis.

Installing a Solid or Semi-Solid Roof

For those who want a roof that provides cover from rain, polycarbonate sheeting is a common choice. Sheets are laid across the pergola beams with an overlap to allow water to run off. It is important to create a slight pitch so that rainwater drains away rather than pooling on top. Corrugated plastic sheets can also be used, with fixings placed at the crests to avoid leaks. For a more robust design, lightweight metal sheets or even tiles may be installed, but in these cases the pergola may require additional support posts and cross bracing to handle the extra load.

Fabric Roofs and Shade Sails

Fabric is a popular choice for pergola roofing as it is versatile and relatively inexpensive. Shade sails can be tensioned across the beams using brackets and fixings, while retractable canvas covers offer the option of rolling back the roof when full sunlight is preferred. These covers are best removed during the winter or in strong winds to prevent damage. The main benefit of fabric is the softer look it creates, making the pergola feel more like an outdoor living room.

Maintenance and Longevity

The durability of a pergola roof depends on the materials chosen and how well it is maintained. Timber battens should be treated regularly with exterior wood stain to prevent rot. Plastic or polycarbonate sheets should be checked for cracks and cleaned to avoid dirt build-up, which can reduce light transmission. Fabric covers may need replacing every few years depending on exposure to the weather. Carrying out regular checks ensures that the roof remains secure and continues to provide the desired level of protection and shade.

Costs to Consider

The cost of making a pergola roof varies widely depending on the material. A basic timber slatted roof may cost between £100 and £300 depending on the size of the pergola. Polycarbonate sheets typically cost around £15 to £25 per square metre, while corrugated plastic can be a little cheaper. Fabric shade sails start at around £50 but higher quality options will cost more. If opting for a more permanent metal or tiled roof, the costs can rise significantly and may require professional installation.

Final Thoughts

A pergola roof can make an outdoor space far more versatile, providing shelter, style, and comfort throughout the year. By carefully choosing the right materials, following best practices for installation, and carrying out regular maintenance, homeowners can create a feature that not only looks attractive but also adds value and usability to their garden. Whether opting for a simple slatted design or a solid roof for weather protection, the key is to plan well and build with durability in mind.