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.
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 normally attend a course on how to install the membrane, and they normally offer a long warranty on the finish. EPDM manufacturers quote lifespans of 50+ years.
The edges of the roof are fitted with special trims, some of which include drip trims which direct moisture from the roof into the rain water guttering.
EPDM has a dark grey / black appearance, some suppliers try to soften the appearance by adding a layer of stone chippings over the roof.
EPDM membranes are often part of the build up of living roof systems.
Fiberglass roofing systems have been used on flat roof buildings for more than 30 years, and like other systems commonly chosen for garden office roofs that have a long maintenance free lifespan – they often come with warranties of 30 years.
The main fiberglass sheeting is normally 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 and metal colours to brighter finishes. The sheets can either be smooth or ribbed and some suppliers offer slate tile effects.
Living roof coverings are a desirable finish for may garden office buyers, they not only look great, but the are also good for the environment and add an additional layer of insulation to the office.
Although turf and meadow roofs are a option, sedum roofs are by far the most popular option for a garden office, because they are light weight, easy to maintain and offer year round interest.
Living roof systems are built up in layers, they often incorporate a 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 light weight.
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, whilst other mixes can ensure a 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!
Insulated roof panels
A popular option on flat roof designs (also on gentle pitches) are insulated roof panels.
These large sheets are made by the leading insulation manufacturers like Kingspan and comprise of an internal finish, the insulation and then the outer layer of the roof.
The sheets are profiles and lock into one another, being 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.
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.
Insulated roof panels
The insulated panels we described in the previous section can also be used on shallow pitched roof such as mono pitched roofs.
The panels often have a coloured external finish such as grey or dark green and this will obviously be more visible on a sloping roof than a flat one.
Asphalt shingles have been a popular option since the early days of garden office design.
Offering the appearance of a tiled roof, asphalt shingles come in several colours. They are an entry level option on many garden office designs.
Asphalt shingles come in strips of three tiles, they are laid in layers, staggering the joints on each layer. The shingles have a bitumen strip on the back of the the tiles which is heated to glue the tile down onto the tile below, this stops the wind catching under the tiles.
Asphalt shingles have a stone finish which creates a durable finish, and they have an estimated life span of 20+ years.
Slate tiles whether real or man-made are an option on pitched roof designs. They are a very heavy roof covering so they can only be used on the more sturdy garden office builds.
Slate tiles take skill to install so have high price tags, so you’ll probably only see them offered on bespoke design garden offices.
An import from American timber frame houses are metal tiles. These interlocking tiles can be plain metal or have a stone chipping covering which not only adds extra protection but also adds colour to the tile.
These metal tiles create a roof that looks similar to a slate tiled roof, but because they are made from metal are much lighter weight.
An option we have only seen on high spec bespoke garden office designs is seamed metal roofing.
Often finished in zinc, seamed sheet metal roofs have a very modern feel, and contrast well with cedar cladding and grey joinery.
It is a specialist job to install this roofing system, and the installer will bring their machines to the site and cut each sheet to length and role the joints between each panel.
Concealed rainwater guttering systems can be created using the roofing material, creating a very streamlined effect.
Cedar shingles have always been a popular option for garden offices. Like cedar cladding they start out a reddish brown cloud and will weather to a silver colour in a couple of years.
Each shingle is a different width so an attractive hand finished look is created. The ridge of the roof has cedar ridge caps which really finishes the roof off.
Because wood has good thermal properties a cedar shingle roof adds an extra layer of insulation to the office.
Cedar shingles need to be fixed with stainless steel nails as the resins and oils in the cedar can corrode non ferrous fixings – check with your supplier that they do use stainless steel fixings.