I have been studying the NZ Building Biology and Ecology online course. It is a great course and goes through a lot of information and practical tips for creating healthy homes. This looks at things like building materials, sustainability, site planning, toxicity and EMF. This was my first assignment for Module 1
When looking at sustainable and healthy building, there are different aspects to consider. These can include the sustainability of products, location of production, energy use, toxicity of products, and effectiveness of the product or method in constructing a water-tight building with a healthy fungal ecology. Due to our own personal experience of mould affecting our family’s health, we prioritized the latter when we built our home but we also wanted to consider the other aspects as well.
Our buildings and homes are an extension of our bodies and our health. They have been referred to as our third skin. The relationship between our environment and our health is well established, with indoor air quality being one of the most important and overlooked aspects of health. We each take around 20,000 breaths per day, and it is estimated that around 90% of our lives are spent indoors. Poor indoor air quality can be caused by a multitude of factors including chemical off-gassing from building materials, CO2, and biological contaminants like mould, bacteria and mycotoxins. These can lead to a huge variety of health problem including respiratory conditions, neurological conditions, skin issues, gastrointestinal conditions and certain types of cancers.
When we became aware that indoor mould was causing health problems for us, we also became aware of the extent of the problem – both in New Zealand and worldwide. While mould is everywhere and there is a normal fungal ecology within a home, many homes in New Zealand have water damage and it has a huge impact on our health, our buildings and our society. Within a water-damaged building, there are not only mould spores, but mould fragments, mycotoxins, bacteria, endotoxins and microbial VOCs. This “microbial stew” can cause multi-system, multi-symptom illnesses. The water-damaged building being the cause of these illnesses is often overlooked, as many people only associate mould with respiratory symptoms and allergies.
This experience directed our attention towards creating a healthier home for our family. While creating a home with a normal fungal ecology was the priority, using non or low-toxic materials was also important as we had chemical sensitivities. Sourcing more sustainable materials was also important. We found that there wasn’t always an obvious best choice when it came to materials, and we were often weighing up between different elements (ie. toxicity, cost, sustainability). For example, we avoided second-hand materials because of our sensitivity to mould and knowledge that porous materials like wood can contain mould and mycotoxins. We also had to sometimes choose between which material was less toxic, and which would help reduce mould in the home ie. treated timber in certain areas.
Mould can grow within a home when there is a water source and a food source. Modern homes supply plenty of food substrate, and water can come through water intrusions (ie. leaks, floods, plumbing leaks or excess humidity). Designing and building a house to minimize the chance of water leaks and excess humidity should be a priority when it comes to sustainability. A leak or mould problem can lead to costly renovations and wasted materials, as well as having a huge potential impact on our health which has flow on effects into the economy and society.
There are some simple solutions to reducing the chance of mould such as keeping your roof simple (ie. gable, or mono-pitch with minimal complex joins), choosing good land to build with adequate drainage and making sure the house doesn’t grow mould during the building process (ie. wet timber and timber with mould already on it). Some other ideas are to have plumbing connections visible through an access panel so they can be checked for leaks, the use of leak detectors, and reducing the use of gib in wet areas. There are varying approaches to constructing a healthy home, and we are still learning about the differences and benefits of each method. For example, passive houses create very energy efficient, air-tight homes and rely on mechanical ventilation to maintain the air quality in the house. We experienced this method in one of our tiny-houses and were impressed with how well it managed temperature and humidity. However, this construction method uses a lot of materials which are synthetic (ie. building wraps and tapes). In contrast, there are also methods like a rammed-earth house which uses more natural and sustainable materials, but relies on breathability of the walls to regulate the humidity. I am interested in learning more about these methods, and how effective they are in reducing mould and air quality problems.
When thinking about creating a more sustainable future, living in communities has many benefits and this can also be applied to reducing the number of water-damaged buildings. One idea of a community layout is having a central building which has all the community cooking and bathroom needs, while having separate living houses which have minimal or no plumbing in them to reduce the chance of water damage happening. These living and sleeping spaces could possibly have outdoor kitchens, bathrooms and composting toilets if needed. If an issue occurs in the cooking and bathroom area, then it won’t affect the health of the living/sleeping areas, and the cost of remediation can be shared between the community. This “campground” style communal kitchen could foster more community shared meals. This could also potentially reduce the cost of council building fees, and reduce the size needed for a home. Encouraging the use of outdoor cooking, showering and bathing would be another way to reduce the risk of mould-related problems, and re-using the greywater in the gardens can help with water usage.
This could also be replicated on a smaller scale in residential areas. For example, on a 800m2 section there could be a common living and kitchen area with two separate bedroom dwellings. This could be inter-generational living or a small community. We are currently living in a 30m2 consented living area with a small bathroom and kitchen, with an additional 30m2 consent-free bedroom area (with no plumbing). We have found this configuration makes us go outdoors more, and the small dwellings are very easy to heat. We mostly use our outdoor bath and shower, which has reduced humidity problems in our house, and the waste water feeds a thriving banana grove.
I believe that mould and water-damage is the biggest health problem when it comes to indoor living. Finding ways to create and maintain homes that have good air quality will have a huge impact on the occupant’s health, and this benefits communities and society as a whole. Ideally, this would also be done in a way that uses natural and sustainable resources but if this is not always possible, the overall impact on the planet and health is still very beneficial.
