Is polycarbonate the new cedar?
A pink and blue pop-up pavilion by the River Thames, the glowing wall of an art gallery in Sao Paulo and an energy efficient insulating façade on an old house in northeast Spain. What do all these buildings have in common?
The answer is polycarbonate. Once a useful, if basic, material used in greenhouses and roofs, polycarbonate is now a Thoroughly Modern Material. Aside from the aesthetic possibilities it offers to projects like those above, polycarbonate has a plethora of other attributes which could help explain its increasing attraction to architects.
Here is a small list of 5 benefits of using polycarbonate in building and construction:
1. It’s easy to bend
Polycarbonate is a thermoplastic, which means that it has some very useful properties. It can be easily formed into a variety of shapes and structures and can be cold-bent on site to form a curved surface.
Because it is a thermoplastic, polycarbonate can be heated, cooled and reheated again without any degrading effects. This means that it is 100% recyclable.
2. It’s resistant to shock and fracture
When compared to glass, a solid polycarbonate sheet has a far higher impact. This is extremely useful when it comes to the transportation, handling and installation phases of any project.
Once the building is in service, polycarbonate provides far greater resistance against hail, falling branches and other objects than the resistance of glass, acrylic or GRP. Additionally, unlike GRP, polycarbonate does not become more brittle with age.
Polycarbonate shock- and fracture-resistance properties reduce potential expensive repair and maintenance costs.
3. It’s less than half the weight of glass
With a density of 1200kg/m3 compared to 2800 kg/m3 for glass, polycarbonate offers benefits in terms of structural design. Reduced dead weight loading from cladding or roofing elements can lead to reduced size structural members and foundations and, hence, cost savings.
Equally important are the manual handling implications of a lower-weight material. Transportation, lifting and manoeuvring into place are all become easier, and potentially safer because it’s not fragile, operations when using polycarbonate in building and construction.
4. It's a good insulator
Polycarbonate thermal insulation properties help to explain why it is becoming an increasingly popular choice for cladding and roofing. Multiwall polycarbonate sheets create additional air pockets around the building, improving its thermal performance.
Single-layer glass has a U-value of 6 W/m2K while the U-value of polycarbonate roofing materials ranges from 3.5 W/m2K for a 6mm twin wall to 2.1 W/m2K for a 16mm five-wall sheet (XL).
Polycarbonate is also a good noise insulator. That’s why you’ll often see flat polycarbonate sheets, either transparent or coloured, used for acoustic barriers by busy roads, construction sites or railway lines – or to form partitions in an office fit-out or a clothing store.
5. It transmits light
While this may seem like a statement of the blindingly obvious, there will be some for whom the word ‘polycarbonate’ conjures up visions of yellowing plastic and hazing. While this remains a problem for GRP, this isn’t true for polycarbonate.
Polycarbonate transmits around the same amounts of light as glass does and much more than GRP; In addition, polycarbonate can be as transparent as glass while GRP is translucent and is not a full see-through product.
Most polycarbonate sheeting is treated with UV protection on one or both sides in order to protect it from potential UV radiation, thus extending its life. Recent developments also include special coating and tints that reflect infrared radiation outwards, reducing solar gain, while still allowing natural light to pass through. A diffuser matte finish can be used to reduce glare and disperse light if desired.
All this and colour too
While the benefits to the environment of natural lighting are well-rehearsed and understood – lower artificial lighting usage, lower HVAC costs and, of course, carbon savings – employers and specifiers are only just beginning to appreciate the impact of natural light on wellbeing.
The positive impacts of natural, rather than artificial, light include lower stress levels and better sleep patterns, leading to higher productivity and fewer sick days.
Cladding, glazing and rooflights — by using polycarbonate in building and construction — offer designers the opportunity to optimise natural light in buildings, at potentially lower capital and operational costs than competing materials. That makes it a truly sustainable choice. And we haven’t even talked about the possibilities that an almost infinite choice of colours brings…