-Mikala Dind
In this six-part series, Narara Ecovillage member Mikala Dind shares her knowledge about what makes houses healthy or unhealthy. While this article is about existing homes, the information will definitely assist anyone seeking to build a home.
LOCATION
While “location, location, location” might be the catch cry for real estate agents because it indicates access to shops/public transport/schools, has views, or fits a certain lifestyle, other questions need to be addressed in respect of your home’s location.
For instance, while living near a main road can be convenient, it will also bring air pollution, such as diesel particulates, that you may need to filter out from your internal air space. Nearby industry can also produce air pollution (eg silica from cement recycling, dust, soot, noxious gases). Ideally it is good to be 500m from main roads, 2km from light industry and 8kms from airports.
Heavy industry (including mining) can generate air particulates that travel long distances (for instance, coal dust can travel 10kms from coal piles). Thus, it is a very good idea to ascertain where the predominant breezes come from, and research if any industry is located in that up-wind direction. (This Bureau Of Meteorology page provides wind data for 81 locations around Australia.) If you already live near any such facilities, a good air purifier (that has a HEPA filter, a carbon pre-filter, and does not generate any ozone) will remove particulates from the internal air of your home.
Similarly, being near a golf course, turf farm, park or agricultural area may mean that herbicides might drift into your property (in particular your breathing space). A distance of 2km will reduce your exposure to these toxins.
Another consideration, if you are a light sleeper, is being close to train lines and main roads, which may lead to difficulty sleeping (and then require installation of double glazed windows).
It is also important to find out the previous use of the site. Was it a waste facility, farmer’s market, service station, chemical refinery, or meth lab? Did the previous owner paint or use glues/solvents at home? Previous uses may have led to toxins leeching into the soil or into the fabric of the home itself, and thus now contaminate garden beds/veggie patches, or be off gassing into the home.
If you have allergies (eg hayfever), look not only at the vegetation around the house but also the surrounding areas (particularly in the direction of predominant breezes).
Image: Wind speed and direction indicators: Wind Roses for Selected Locations in Australia
ORIENTATION
The way a home is oriented (north, south etc) will influence many things including warmth, cost of heating/cooling, condensation etc. I am not an architect, so will only touch briefly on some of these issues. However, a fabulous resource for passive design is Your Home, a free guide to environmentally sustainable homes in Australia.
Image: Your Home
Heating and cooling
In order to gain maximum benefit from the sun’s light and heat, a home should generally face north (unless it is in the tropics, where facing south will keep the house cooler). Having larger windows/glass sliding doors on the northern side will also take advantage of the solar input to your home. (Don’t forget, glass not only allows heat in, but also lets it escape once the sun goes down. Thus curtains or blinds will reduce heat loss during the night.)
Given that there is usually no direct sunlight/heat entering from the south, fewer windows on this side will mean less heat loss (which is particularly important in winter, while in summer use open windows to remove warm air). Similarly, fewer windows on the western side will mean less heat gain from the hot afternoon sun.
Also pay attention to the surrounding landscape (ie the 5kms around the site). Are there hills/trees to the west that mean that the sun will “set” early? Get a shadow map generated for your home which will give you a good idea of the available sunlight throughout the year. You can also go to SunEarthTools.com to generate a map showing the sun’s summer and winter path over the home.
Image: Solarchoice.net.au
Condensation & mould
The southern side of a house will generally have more problems with overnight condensation as the rooms there get coldest overnight. Combine this with single pane windows, metal window frames and moist air exhaled by sleeping occupants, and you have the perfect conditions for condensation. Either mopping the moisture up or using a dehumidifier to capture it can be the difference between a healthy bedroom and a mouldy one.
Image: Homebuilding.co.uk
I once did an audit for a family who had symptoms of mould illness. When I went to their rental “home” I realised that the owners had simply built a granny flat of sorts below their balcony and pool – on the southern side of their house. In theory it sounds like a good use of space (especially if someone is willing to rent it from you). However, the downside is that the rear half of the flat was either built directly into the sandstone the house was built on, or backed up closely to the damp, dank sandstone beneath the pool. Effectively the flat was a damp cave with a few sliding doors at the front. No cross ventilation or direct sunlight, and constant high humidity (as moisture from the sandstone migrated through the walls), meant this was mould heaven (despite them using a dehumidifier every day). As you can imagine, it was also bone chillingly cold in winter. My advice to them? Move out (though my report did set out a plan B in case this was not possible, as they had recently re-signed the lease). Fortunately the owners let them break their lease. However, I suspect someone else is now suffering from such a poorly designed living space.
Finally, ensuring that your roof extends beyond your walls (to create an eave) means the ground at the base of your external walls will dry out quickly after rain (reducing the likelihood of algae and mould growth) and therefore the risk of increased humidity in the room on the other side of that wall. All windows require decent eaves over them to protect window frames (particularly if they are wooden).
The more your window frames are in contact with sun and rain, the more weathered they will become (which will lead to greater maintenance costs to prevent water intrusion through unnoticed wood rot). Again, note which side(s) of the house get the predominant weather (especially storms).
In the next article I will discuss drains and gutters.