Advice to help you select the ideal balcony material, build method and design to suit your needs, budget and the style of your house.
This balcony serves as solar shading for the huge expanse of south facing glass. Image: Bradley Quinn
Balconies range from bespoke architect designed constructions that wrap around more than one side of a self-build project to small, bolt-on retrofit systems installed by specialist companies. South facing installations may benefit from an abundance of light, but there are benefits to be had from any orientation. ’Even a balcony facing north will get morning and evening sunlight in the summer,’ says architect Adrian James.
Types of balcony
Balconies can be constructed in several ways, and which method you choose will ultimately be determined by how you’d like it to look, the size you want and your budget. A substantial cantilevered design, where the balcony extends out from the house with no visible means of support, complements a contemporary home. Usually made from concrete, steel or timber joists, this type imposes a heavy weight load on the building and must be built into the main structure, making it a relatively expensive option.
Column supports of metal or timber fixed into the ground are a more straightforward and less costly means of support. The posts take the balcony’s weight, conferring minimal weight load on the building, so this type can be retrofitted. Bolt-on systems using brackets or tie rods work effectively for smaller designs and won’t have the physical or visual obstruction of column supports.
Great for giving bedrooms or home offices an outdoor view, a Juliet balcony has a frameless glass balustrade is made from toughened, laminated glass. This comprises two layers of toughened glass with an interlayer between them. A frameless balustrade without a handrail has an ionoplast interlayer that’s even stronger and stiffer, so if both panes break the structure will stay upright and in situ. When teamed with a sliding door, the balustrade is most often fixed internally within the base track of the door frame. If partnered with a bi-folding or hinged door that folds inwards, it has to be fixed externally. This can be done with bolts through the glass into the exterior wall surface or via specialist fixing clamps that connect the balustrade to the door frame.
A small, steel-framed bolt-on balcony will cost around £3,000, while a cantilevered one built with glass balustrading and expensive alloys will cost upwards of £8,000.
A green oak balcony by Roderick James wraps around two sides of this oak-framed house
Choose a frame
The framework for your balcony will be made of either metal, concrete or timber. Steel frames are hot-dip galvanised to prevent corrosion and rust and can be left bare or powder-coated to add colour and a more uniform finish. Cast aluminium is virtually indistinguishable from cast iron in look and feel and is the material of choice for period-style balconies. It’s about one third the weight of cast iron so requires fewer structural posts and none of the extensive concrete foundations, which can save time and money during the installation. Timber frames are made of either green oak, Douglas fir or larch. Oak is the strongest, requires very little maintenance and is one of the few materials that increases in strength with age, but is also the most expensive.
This balcony from Adrian James Architects is part of a bedroom suite.
Planning permission is required for any balcony that you intend to walk on, whether it is added to an existing home or included as part of a self-build or renovation project. Consent may not be needed when installing a Juliet design, which is where the balustrade is fixed up against the exterior wall. But permission will still be required for this option if the property is listed or in a conservation area. In any case, if the balcony has even a slim floor area, it is not regarded as a Juliet so will need consent. Self-build and major renovation projects must include details of any proposed balconies as part of the overall planning application. Issues with the application are more likely to arise in urban areas, where neighbours are overlooked – the sticking point is often the neighbours’ privacy. A new ground-floor extension may create the opportunity for a roof terrace or balcony at first-floor level. But even if the extension falls within Permitted Development (PD) rights, using the roof space for a terrace will require planning permission.
Stainless steel posts and handrails by Model Projects are corrosion-resistant
To comply with Building Regulations, a balcony balustrade must be at least 1,100mm high and, if there are gaps between any elements, they can be no wider than 99mm. Options for materials include wood, metal and glass, which can also be used for the balcony floor. Structural glass balustrading can be designed with minimal or no framing, which is useful when there are nice views. ‘Choose a specification that has minimal deflection to reduce any movement when leaned on,’ says Rebecca Clayton, marketing director at IQ Glass.
A glass floor by IQ Glass with a sandblasted finish to make it anti-slip and ensure privacy.
When you build out on an upper floor with a window below, the daylight coming into the rooms beneath can be reduced, but there is a simple way to overcome this issue. ‘Include a glass floor, typically made from triple-layer, toughened glass panels designed by a specialist installer,’ says Jason Slocombe at Le Lay Architects. Structural silicone joints can connect multiple panels within the floor and an anti-slip finish is advised. Sandblasting is the standard slip-resistant finish, giving a translucent look. Alternatively, a ceramic glass frit pattern, such as a dot matrix, can be added to the top layer so it becomes structurally bound into the glass to add traction and maintain transparency.
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