Garden office roof coverings

Your choice of roof covering for your garden office will not only protect the structure of the building but will also have a significant effect on the appearance particularly if you are choosing a pitched roof building.

How much choice you have will depend on the shape of the garden office roof you have chosen:

• Flat roof coverings
• EPDM
• Fibreglass
• Torch on bitumen
• Living roofs
• Insulated roof panels
• Pitched roof coverings
• Asphalt shingles
• Cedar shingles
• Eco Slates
• Metal tiles
• Seamed metal roofing

Roof coverings for flat-roofed garden offices

Although the industry often refers to them as flat-roofed garden offices, they are not flat. The roof will definitely have a fall designed into it, so that water can run off without settling on the roof. The actual angle of the pitch depends on the run of the roof. The deeper the roof, the greater the angle of the fall.

Typically, a 'flat-roofed' building has the slope running from front to back. In a few situations, it will slope from side to side.

These are the most common roof coverings used on these shallow pitched roof.

EPDM roofing

EPDM roofing has become the most popular finish on flat roof garden offices over the last few years.

EPDM is a thick rubber sheeting which has been used extensively on commercial buildings for decades and has now been widely adopted by the garden office industry.

EPDM is laid in whole sheets so there shouldn't be any joins in the system. Garden office suppliers usually attend a course on how to install the membrane, and they usually offer an extended warranty on the finish. EPDM manufacturers quote lifespans of 50+ years.

The edges of the roof are fitted with special kerbs, some of which include drip trims which direct moisture from the roof into the rainwater guttering.

EPDM has a dark grey / black appearance; some suppliers try to soften the presentation by adding a layer of stone chippings over the roof.

EPDM membranes are often part of the build-up of living roof systems.

Fibreglass roofing

Fibreglass roofing systems have been used on flat roof buildings for more than 30 years, and like other systems commonly chosen for garden office roofs they have a long maintenance free lifespan. They often come with warranties of 30 years.

The main fibreglass sheeting usually is fitted in one piece, so there are no joints liable to leak. The edges have specially designed trims which can include drip trims so that water runs into the guttering of the building.

Fibreglass roofing comes in many colours, from bitumen and metal colours to brighter finishes. The sheets can either be smooth or ribbed, and some suppliers offer slate tile effects.

Torch-on bitumen

A few companies offer traditional torch-on bitumen roof systems. The multi-layer build-up includes layers of reinforced polyester membrane that are bonded together by heating bitumen to high temperatures. This is a traditional option offering a long maintenance free lifespan.

Living roofs

Living roof coverings are a desirable finish for many garden office buyers. They not only look great, but they are also good for the environment and add an additional layer of insulation to the office.

Although turf and meadow roofs are an option, sedum roofs are by far the most popular choice for a garden office, because they are lightweight, easy to maintain, and offer year-round interest.

Living roof systems are built up in layers; they often fitted over an EPDM membrane which waterproofs and protects the structure of the building. On top of this protective membranes are laid to stop the roots from the plants penetrating the membrane. Over this a growing medium is laid, this is designed to provide all the nutrients the plants will need whilst being lightweight.

You could sow seeds and wait for the plants to grow, but most garden office suppliers use pre-grown mats which are laid over the growing medium, and because the plants are already established look visually green from day one.

You can work with your supplier to choose the type of plants used in the roof. Some mixes can create sequential colour throughout the year, while other mixes can ensure an excellent display of summer of flowers.

Living roof systems will need some light maintenance, so you will need to be able to climb up and attend the plants once a year, or so!

Insulated roof panels

A popular option on flat roof designs (also on steeper pitches) are insulated roof panels.

These large sheets are made by the leading insulation manufacturers like Kingspan and comprise of two layers of colour coated steel with insulation in-between. This sandwich forms both the interior ceiling finish, and the protective outer layer of the roof.

The sheets are profiled and lock into one another, and are also fixed into the walls of the garden office. The edges of the panels are boxed in with fascia boards creating a neat finish.

This roofing option is popular with garden office suppliers because it creates the whole structure of the roof, there is no need for roof rafters, so a relatively thin roof section is created. You should ask suppliers what thickness of roof panel they use. They come in varying depths. The thicker the panel, the more insulation it offers and the warmer your room will be.

Internally the underside of the roof sheet is visible. With some brands this is a smooth white finish, with others it is a grooved white finish. The joints where the sheets meet have plastic strips over them.

On large garden offices, this type of roof covering will need some additional support, so you will often find that there are beams visible internally.

Because there is no void in the roof structure with this type of roof covering, you don't have the option of recessing lights into the ceiling. You will find that the lights are fitted to the walls rather than the ceiling.