BUILDING ENVELOPE
Materials matter
Cedral’s Lisa Grosse explains why overheating and resilience are key factors when making decisions about the facade and roof of your home.
H
omes in the UK weren’t designed for the extreme heat that has been setting records, and which
is projected to become a regular occurrence. The Local Government Association has found that 20% of homes in England experience overheating issues now, even during cooler summers. Nearly 38% of the country’s residential
properties were built before 1946 when the norm was to construct to trap the sun and minimise heat loss during mild summers and cool winters. More recently residential design has featured expanses of glass to maximise the sunlight with conservatories, skylights and large glass doors. At the same time, government data shows that two thirds of the homes in the UK need better insulation which would help mitigate the effects of heatwaves. With more intense sunshine, higher temperatures and increased radiation, the UK renovation and homebuilding sector is having to re-evaluate material choices as well as design features to ensure that homes are more resilient. Such extremes particularly affect the performance and fabric of south facing facades. Designing buildings that remain cool in the summer and are efficient for colder weather has become more of a priority to comply with building standards.
While most building materials are designed to withstand some degree of expansion and contraction, excessive heat can push these materials beyond their limit. The impact of expansion and contraction on the building’s fabric can also adversely affect the quality of the indoor environment and the wellbeing of the occupants. Heat or over exposure to sunlight, especially for south facing facades, can result in warping and bulging, and can even affect the structure. For example, a timber facade can not only bleach in colour in consistent direct sunlight but it can also warp and expand. This can damage or create gaps in the facade and as a consequence this could result in a leak later in the year. Stone is highly robust, but like wood, can discolour as a result of constant exposure to extreme
32
www.sbhonline.co.uk
fluctuations in temperature. The materials used for residential
roofing in the are also facing challenges because of more extreme weather. Increasing temperatures could cause blistering or cracking on roof tiles and slates. The sealants could also be affected. This isn’t just about the visible damage caused by heat. At the same time we are seeing
increases in rainfall and wind speeds which could potentially compromise the roof’s durability and result in costly maintenance in the future. The Met ffice measured the highest amount of rain for any 18 month period in England from October 2022 to March 2024, since its records began. The longer and heavier periods of rain have implications for the robustness of roofing tiles and fiings. lder roof structures, for instance, may not have the capacity to support heavier tiles if there are more prolonged periods of stormy and wet weather. With the UK becoming warmer, the choice of material and design for a home’s facade will make a tremendous difference in creating an energy efficient climate-responsive building. The most frequently used options include,
either used on their own or in various combinations: timber, stone, brick, metal, weatherboard, concrete, and glass. And a trend we have seen growing in popularity is fibre cement cladding which has undergone stringent testing to ensure its durability under extreme weather conditions. or roofing the most popular material options have been concrete tiles, clay tiles, asphalt shingles metal and increasingly fibre cement tiles.
Each of these has their own pros and cons in terms of the protection they provide their durability under extreme conditions, their cost and value, both from initial installation to maintenance and replacement.
A ventilated facade makes it easier for your home to be cooler during summer and warmer during winter. An example is the use of a ventilated rainscreen system used with cladding. Having effective ventilated walls can improve thermal efficiency of a home by helping to circulate air flow which in turn helps to regulate the temperature and improve conditions indoors. In hot weather, air can rise to the top leaving space below for cool air to enter and keep the building cool.
nov/dec 2024
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
