Brise Soleil Might Just Be the Most Beautiful Overheating Prevention Method Around — Experts Demystify This Stylish Shading Feature
We all love spaces flooded with natural light, but they can be tricky to keep cool — step forward brise soleil
The best architectural features tend to be those that don't just please the eye, but also carry out an important practical role in enhancing the whole experience of living in a building. This might mean they draw in extra natural light, or perhaps prevent heat loss, even add in some valuable storage.
One of the best examples of one of these pragmatic yet beautiful features is brise soleil — a method of shading expanses of glazing that, in the hands of the right designer, will also help to shape the entire look of a house, adding depth and interest at the same time as allowing for some ethereal light effects within.
Using architectural features to prevent overheating is something that is becoming increasingly important in our climate, so whether you are embarking on an extension or renovation project, or are starting from scratch, brise soleil should definitely be something you are considering. We asked the designers for their views on the best ways of incorporating what is fast-becoming a must-have addition.
What Is Brise Soleil?
Brise soleil is most commonly made up of louvres that project horizontally out from a building over larger areas of glazing.
The jargon of the architectural world can often feel a little intimidating, so let's begin by looking at exactly what the very fancy-sounding brise soleil actually is. In short, brise soleil is a French term, meaning 'sun breaker'.
These sun breakers most often take the form of horizontal fins, louvres or even grids that protrude out from the face of a building, predominately over areas of glazing, with the intention of stopping the full force of the sun's heat from entering a house. Increasingly, vertical brise soleil are also be used, installed in front of windows and fixed glazing.
Far from being just another of those passing architectural trends, architect Caroline Shortt, director of Barc Architects, explains their important function. "Brise soleil acts as external protection against overheating. By shading the glass externally, it stops solar heat before it strikes the glazing, making it particularly effective on south-facing elevations.
"The beauty of brise soleil is that it doesn't block light completely — it still allows an ambient light through and this can be controlled by the direction and angles of the louvres."
Chartered architect Caroline Shortt is director of Barc Architects, a forward-thinking practice with a reputation for blending innovation with sustainability.
Where Does Brise Soleil Work Best?
South-facing elevations tend to benefit the most from horizontal brise soleil.
There is no doubt that there are some really striking examples of brise soleil out there — so much so that it is easy to forget their practical role. It is important, however, to be aware that they aren't always the right fit and need to be specified with care, something that Richard Dudzicki, director of RDA, is keen to point out. "Brise soleil should not be installed automatically on every elevation. A horizontal system is unlikely to provide much benefit to north-facing extensions and glazing, which receive limited direct sunlight. It can also be less effective on east or west-facing windows, where the sun is lower and may pass beneath the louvres. In those situations, vertical fins, external blinds, shutters or carefully positioned planting may be more appropriate."
Caroline Shortt agrees that, in some cases, alternative methods of shading, such as window treatments to keep the heat out, might be more suitable. "Brise soleil isn't always the right fit — particularly on west-facing glass where the late afternoon sun sits very low, or on sites exposed to high coastal winds. In those instances, we look at alternatives, such as deep roof overhangs, recessed glazing, or splayed window reveals that open up views while naturally shading the glass, alongside high-performance solar control glass."
Vlad Diachok, co-founder and lead designer at Diachok Architects, also advocates taking a property-specific approach to solar shading rather than immediately falling back on brise soleil. "We see solar control as something that should respond to the specific space, climate, and desired result, rather than as one standard solution. Across our projects, solar shading elements are used for different purposes, including shading, glare reduction, privacy, protection from direct sunlight, and as part of the architectural expression itself."
Richard Dudzicki is a globally-recognised architect and industry leader within the Passivhaus community. He most recently won Best Green Home 2023, awarded by The Daily Telegraph Homebuilding & Renovating Awards. As founder and director of RDA Architecture & Interiors, based in London, Richard has been at the forefront of sustainable home design for more than 26 years.
Vlad Diachok is co-founder and lead designer at Diachok Architects, an international interior design studio creating refined, highly considered spaces that reflect and enhance the way people live.
How Can You Maximize Its Benefits?
Brise soleil can also work well set over glazed ceilings to stop the rooms below overheating.
As well as making a strong architectural statement, brise soleil is the ideal way to combat the ever-increasing issue of overheating. That said, the success of brise soleil is very much hinged on good design and careful planning, as Richard Dudzicki explains. "The depth, spacing and position of the louvres must be designed to respond to the orientation of the façade, the height and angle of the sun, and the size of the glazing. A successful design should provide shade when it is most needed without making the interior unnecessarily dark throughout the year.
"Its practical functionality also needs careful consideration," continues Richard. "The structure must account for wind loading, drainage and access for cleaning, as leaves and debris can collect between the louvres or in adjoining gutters. When properly designed, brise soleil can become more than a shading device. It can reduce the risk of summer overheating while giving depth, rhythm and identity to the façade."
It's clear, then, that this isn't a feature that can just be slapped on all floor-to-ceiling glazing haphazardly and expected to do it's job — to be worthwhile, professional input is highly recommended, particularly when it comes to getting the size and angles just right, as Caroline Shortt explains. "Sizing comes down to mapping the sun’s seasonal path. We carefully calibrate the depth and angle of timber or steel louvres so that low-level winter sun can penetrate and warm the room, while high, harsh summer glare is screened out."
What Are the Different Design Options for Brise Soleil?
Sometimes a different approach to brise soleil design works better — such as here, where vertical louvres were specified.
Brise soleil takes many different forms, but is most commonly constructed from timber or aluminum — sometimes both.
"We most often use lightweight aluminum, but timber fins are another good option," shares Caroline Shortt. "Sometimes we combine the two, with aluminum angles and wooden louvres."
Caroline goes on to explain the other design options to consider when specifying brise soleil. "Sometimes taking a vertical approach works better, in front or to the side of the glazing to block the harshness of the sun. Louvres can also be fully adjustable so that they can be tweaked according to the time of day or even as the seasons change."
As with the overall design of your brise soleil, the materials chosen for its construction need to be selected with individual needs in mind, something architect Jeff Kahane, founder of Jeff Kahane + Associates, explains is a consideration if you plan on using your brise soleil as a structure on which to grow up any planting. "Brise soleil made with wood slats and supporting fins can often be given an adjacent planting bed so that in the long run it can have climbers growing up to its slats and along much of its length — which can, in time, provide additional shading as well as softening the aesthetic.
Caution needs to be taken if that is the plan and the structural engineer always needs to factor the potentially very considerable weight of mature climbing plants into their calculations. Bespoke wooden solar shades can be designed to cope with those potential imposed loads, whereas my feeling is that this would be difficult, or maybe impossible, with some of the very slender aluminum brise soleil."
Jeff Kahane trained at Cambridge University School of Architecture and established Jeff Kahane + Associates in 1989 after fifteen years' experience working with architects and builders in the design of privately and publicly-funded houses and flats. He has contributed articles to the Architects' Journal and to Building Design, been a visiting critic at numerous student assessments, and is the author of Local Materials: a Self Builder's Manual. He has served on several occasions as an assessor for the RIBA`s annual London Region Awards and is currently on of the RIBA's invited panel for student mentoring.
Can You Retrofit Brise Soleil?
While brise soleil can be retrofitted, it tends to work best when designed in from the start.
If you are only just getting around to addressing your home's overheating, you may well be wondering whether brise soleil is something that can be added on and how much disruption is likely to be involved, particularly if you plan on living in your house while renovating.
Richard Duczicki feels that this is a feature best designed in from the offset. "Brise soleil works best when it is treated as part of the architecture rather than an addition applied at the end. At Pitched Passivhaus (above), the external brise soleil is integrated across the rear elevation, above the large areas of glazing."
"Incorporating it works best when integrated into the structural design early on, ensuring the louvres feel like a natural part of the architecture rather than an afterthought," agrees Caroline Shortt, although she does point out that they can be retrofitted if structural requirements are properly assessed. "You can get off-the-shelf models, or have them made-to-measure. You just need to be careful with the downward load and check your wall can take the weight. Most brick or block houses will be fine, but with timber frame you might want to take extra care."
Jeff Kahane goes on to explain that, while retrofitting might not be ideal, it is certainly not impossible. "The brise soleil we have designed needed to be incorporated into the overall design of the new building works from the very start so as to avoid the need for any large brackets being fixed to the face of the walls, which was essential for our clients. However, if having those visible brackets is not a problem, and the appointed structural engineer can confirm that the wall can take the proposed loads, then the options for potentially using an 'off-the-peg' brand of brise soleil will be greater."
FAQs
Do Brise Soleil Only Suit Modern Homes?
While slatted louvres often spring to mind when thinking about brise soleil, grid-patterns can also be used.
There is no getting away from the fact that the majority of brise soleil is seen attached to striking modern homes — but can owners of traditional properties also benefit from their sun-shading abilities without them looking out of place?
"There are definitely ways of adding sun shading to period houses — just think of the beautiful verandas with overhangs seen on many Victorian properties," says Caroline Shortt. "You can get really slimline, minimal metal brise soleil too that take away that harsh glare while being barely visible."
It is also worth noting that, while brise soleil won't usually require planning permission, if you are adding it to a listed building or one in a conservation area, you may well need to make an application.
Along with keeping the inside of your home cool, brise soleil are also a useful way to shade a patio — and if you choose a design with louvres that can be closed, they can provide protection from the wind and rain too once the weather changes.
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