How to Build a Shed Roof

Building a shed roof is a project that many homeowners take on as part of creating a new garden building or refurbishing an existing structure. A well-built roof not only protects the shed from the elements but also adds strength and durability to the entire building. Understanding the materials, methods, and legal considerations involved will help you to create a roof that is practical, long-lasting, and compliant with UK standards.

Types of Shed Roofs

The first step is deciding on the type of roof you want to construct. The two most common designs are the pent roof and the apex roof. A pent roof has a single slope which makes it straightforward to build and ideal for placing against a boundary fence or wall. An apex roof has two sloping sides that meet in the middle, creating a more traditional look with added internal height.

The choice between the two often comes down to appearance, space requirements, and intended use. For example, if the shed will be used as a workshop, an apex roof provides more headroom. A pent roof is often chosen for storage sheds where simplicity and a compact design are more important.

Materials Needed for Construction

To build a shed roof you will need timber for the rafters and frame, plywood or oriented strand board (OSB) for the decking, and roofing felt or shingles for the weatherproof covering. Pressure-treated timber is recommended for longevity as it helps resist rot and insect damage. The size of the rafters depends on the span of the shed, with 50 x 100mm timbers often sufficient for smaller structures. For larger sheds, you may require stronger sections such as 50 x 150mm.

Roof coverings vary in cost and performance. Roofing felt is the most economical choice, usually costing between £40 and £80 to cover an average-sized shed roof. Felt shingles provide a more decorative finish, while lightweight corrugated sheets made from bitumen or metal can add durability. Expect to spend between £80 and £200 depending on the chosen material.

Framing the Roof

The framework forms the backbone of the roof. For a pent roof, this involves fixing rafters across the width of the shed at the chosen slope, then attaching a sheet material such as OSB on top. For an apex roof, you will need to cut rafters with angled ends so that they meet neatly at the ridge. These are then fixed in pairs to form trusses. The trusses are positioned at regular intervals along the length of the shed and secured to the wall plates at the top of each wall.

When constructing the frame it is important to ensure everything is square and level. Accurate cutting and measuring at this stage will make the roof stronger and easier to finish. Using metal brackets or timber screws adds stability and ensures the structure can withstand wind and rain over time.

Adding the Decking

Once the frame is in place, the next step is to fit the roof decking. Sheets of OSB or exterior-grade plywood are laid across the rafters and fixed securely with nails or screws. The boards should be staggered so that the joints do not line up, as this increases the strength of the roof. Small gaps of around 2 to 3mm should be left between sheets to allow for natural expansion.

If you are using corrugated sheeting instead of boarding, it can be fixed directly to the rafters. However, most shed roofs use boarded decking beneath the final roof covering for stability and weather protection.

Weatherproofing the Roof

The weatherproof covering is the most important stage for protecting your shed from rain. Roofing felt is the most common option, applied in overlapping strips from the bottom of the roof upwards. Each strip is nailed into place and overlapped by the next, ensuring water runs off without seeping inside. Ridge pieces or capping strips are used at the top of apex roofs to seal the join between the two sides.

Shingles or corrugated sheets are installed in a similar way, with overlaps ensuring that water flows downwards and off the roof. Whichever material you choose, careful attention to sealing edges and overlaps will greatly extend the life of the shed.

Costs of Building a Shed Roof

The cost of building a shed roof varies depending on materials and size. For a small shed, expect to pay between £150 and £300 for timber, boarding, and felt. Larger sheds or those using premium coverings such as corrugated metal sheets may cost £300 to £600. If you hire a tradesperson to construct the roof, labour can add another £150 to £300 depending on complexity.

Do You Need Planning Permission?

In most cases, building a shed roof does not require planning permission provided the shed itself complies with permitted development rights. This means it must be a single storey, not exceed 2.5m in height when placed within 2m of a boundary, and not cover more than half of the garden. If you plan to build a particularly tall shed or live in a listed property or conservation area, you should check with your local planning authority before starting work.

Building Regulations Considerations

Small garden sheds are usually exempt from building regulations, but the structure must still be safe. Roofs must be properly secured and able to withstand wind loads, especially in exposed areas. If you intend to insulate or wire the shed for electricity, separate regulations may apply. Always ensure any electrical work is carried out by a qualified person who can self-certify compliance.

Insulating a Shed Roof

If the shed is going to be used as a workshop or hobby space, you may want to add insulation. The simplest method is to fix rigid insulation boards between or beneath the rafters before adding an internal lining such as plywood. This helps regulate temperature and prevents condensation. While insulation increases the cost, it makes the shed far more comfortable to use year-round.

Maintenance and Longevity

A shed roof can last anywhere from 5 to 20 years depending on the covering used. Roofing felt generally lasts around 5 to 10 years before needing replacement, while shingles and corrugated sheets often last longer. Carrying out regular checks, especially after heavy rain or wind, will help identify small problems before they develop into leaks. Reapplying treatments or resealing joints can add years to the life of the roof.

Conclusion

Building a shed roof is a manageable project for many homeowners, provided the right materials and methods are used. By choosing a suitable design, constructing a strong frame, and applying a reliable weatherproof covering, you can create a roof that keeps the shed dry and secure for many years. With careful planning and attention to detail, the cost is relatively modest and the end result is a valuable addition to your property.