Module 1: Comfort, sound insulation and resilience
If you’re working on a building project and need help specifying your materials, checkout the following.
In the Western world we spend around 90% of our time indoors and 65% of that is at home. Because it is our most significant financial burden, most of us form strong connections with our homes, a connection which can strongly affect our health, positively and negatively, without us necessarily realising.
Research from the UK Green Building Council has highlighted the link between a healthy living environment and the physical and mental health of those living in that environment. Poor indoor air quality and large swings in internal temperatures have significant effects on occupants physical health.
Noise and an uncomfortable internal environment have further, significant effects on occupants sleep and mental health, an area which is responsible for just over 25% of the disease burden on the NHS.
As buildings become more insulated and more airtight it becomes more important to maintain comfortable even temperatures and good air quality inside. The use of very lightweight, ‘high performance’ synthetic insulation materials can contribute to higher levels of VOC’s (volatile organic compounds, known to be detrimental to health) and offer little protection against overheating in the summer. Due to their lack of mass they also offer little resistance to sound, resulting in external noise being easily heard inside and vice versa.
Climate change is expected to increase average temperatures but also to increase weather variability. The likelihood of summer heatwaves, sudden cold snaps during winter and heavier rainfall require us to design buildings beyond today’s minimum requirements, to make buildings more resilient.
Building materials that can buffer sudden external changes do not require the occupants to suddenly change their behaviour or the settings on their environmental control systems (heating, cooling, MVHR). This creates homes that can adapt to changing weather patterns at a steady rate, giving those living in them a sense of control over their environment.
1.2 The impact of natural materials
The combination of heavyweight insulation materials, such as wood fibre insulation, and high mass internal linings, such as clay boards or masonry walling, can create buildings which can largely regulate their internal temperatures by themselves. Add in a mechanical ventilation system with a summer bypass and you have a very low energy way to keep the internal environment at a healthy, steady, comfortable temperature for the occupants. Some natural fibre insulation materials (along with all timber products) do contain very low levels of natural VOC’s but they do not generally cause health issues with normal ventilation and so a good ventilation strategy is also important.
Wood fibre insulation products are extremely good at absorbing both sound and heat. The combination of high density external boards (for rendering and cladding over) and lighter weight flexible wood fibre batts results in a wall or roof construction that isolates occupants from external noise and minimises heat penetration during the summer.
This ensures the building stays cool and quiet, ensuring the right conditions for relaxation and sleep and so the use of these strategic combinations of simple materials and systems has a profound effect on the comfort experienced in a building and therefore on the health of it’s internal environment.
As an example of how well wood fibre compares to polystyrene in terms of sound absorption see the below video using two boxes of equal thickness and equal U-value.