While the last post looked at conceptual flaws in the stages of design and planning, this list highlights bad home design decisions that can adversely impact home comfort and human health:
Bad Home Design Decisions: Toxic Building Materials
1.) Sawdust Wood for Sheathing (OSB, MDF)
Most modern-day homes are built with Oriented Strand Board (OSB) and Medium Density Fiberboard (MDF). These are technical ways of saying houses are built out of sawdust and glue. While I applaud the attempt to reuse materials and minimize waste, these products are loaded with toxic binding and anti-mold chemicals (formaldehyde, for one), and fall apart with moisture.
I think the fact that we are resorting to these materials is a sign that we are going in the wrong direction. We need to adopt a more holistic view of shelter and think about growing next generation’s building materials when we build our home. I’m personally looking to natural building, which aims to balance environmental impact, performance, indoor health, aesthetics, and long-term social costs. Buildings can be built from wood, straw, clay, hemp, and a plethora of other materials.
2.) Vinyl Siding
Speaking of nasty chemicals, vinyl siding is one of the most horrible building materials on the market, period. It is toxic, has a short life span, looks terrible and emits volatile organic compounds (VOC’s). Its manufacturing process is also horrible for the planet. As if that weren’t enough, when vinyl siding catches on fire, it can burn so hot that it can ignite adjacent houses.
Don’t believe me? Do your own research. Go talk to your neighbourhood fire marshal. Check with local builders. Do an internet search. We are already surrounded by fire retardants in our beds, blinds and couches. Our paints offgas VOC’s. Our water systems exude chlorine, one of the worst offenders when it comes to indoor air quality, every time we flush the toilet or take a shower. No more. I’m leaning towards going all-natural when selecting a good covering material. My home will likely be straw bale, clay wood chip or light earth clay with a clay-based render and plaster. With the right eaves and maintenance, it will have a lifespan measured in centuries instead of years. It will also be non-flammable, produce no offgases and works with water instead of against it.
Bad Home Design Decisions: Windows
3.) Poor Window Selection
In our cold northern climates, windows are the weakest links. A typical wall has a R-value between 8-20 (still too low, in my opinion), while an average window as an R-value of 2-3. Of course, poorly insulated windows are much cheaper. One of our biggest issues in North American is our attitude toward homes. In many parts of Europe, homes are built not only for the next generation, but several down the road. We need to change our mindset towards seeing homes as disposable and temporary things. If you are choosing windows, do yourself a favour. Pick something that will keep you warm and will last a long time.
But just as easy as it is to underglaze it is also easy to overglaze the windows on a building. Overglazing can lead to an uncomfortable home that overheats in the summer and becomes difficult to warm in the winter. Many people are surprised to discover that passive solar guidelines only recommend between 12-20% of their southern sun-exposed wall be covered in glass. Anything more than 12% and additional thermal mass needs to be added. More than 20% and the building will overheat and cause stress on its inhabitants. Also, take care when putting in large glazed northern windows. Northern light is wonderful to work with, but those windows typically lose more energy than they gain.
There are many excellent books written on passive solar design. If you are planning to build a home, do some research and learn to build it to run on the sun and to make it last centuries. Society sorely needs this level of leadership.
5.) Lack of operable windows and ventilation
While windows light the house, operable windows allow the home to breath. Many people reduce the number of operable windows due to cost, but I think that’s a mistake. One of my favourite homes to visit is in the East Kootenays in British Columbia. A covered deck wraps around the house and keeps the solar gain down. The entire lower story is glazed with many operable windows. When the windows are open, fresh air flows in and makes you feel like you’re in an expansive space. When we forget windows, especially operable ones, homes can feel a bit like prison cells.
To optimize your home’s natural ventilation, you can check out programs that simulate airflow through a structure. They can help you quantify how many windows you need and where to place them.
Bad Home Design Decisions: Missing or Lacking Features
6.) Undersized Eaves
Eaves are essential for keeping a home cool and dry. Small eaves have become the norm, especially in cities where people attempt to maximize their indoor living space on 25-foot lots. I once spoke with a stucco installer who cursed these new homes because they constantly get called back to repair the water damage directly caused by undersized eaves.
If you want a house that’s going to be comfortable and durable, you need large eaves. There are many eaves design resources online that focus on the following objectives:
- They keep the rain off the walls.
- They eliminate summer solar gain.
- They allow winter solar gain.
Correctly sized eaves fulfill all of these criteria. In addition, why not consider turning large eaves into a wraparound deck that you can use on warm summer evenings? Screen it in and you can sleep outdoors in total comfort!
7.) Lack of Vestibule/Air Lock
Modern homes have largely removed this intelligent energy-saving feature. Vestibules act as airlocks that keep extreme cold air out when people come and go. They add dead space that increases the insulation value of entrances while controlling infiltration. They also provide storage for items that don’t need to stay at room temperature. I’ve been people use them to get farm dogs out of the extreme cold without having to bring them completely inside.
8.) Lack of Mud Catcher in Vestibule
The best vestibules I’ve seen have mud grates that allow you to scrap your shoes and boots before putting them away. This feature keeps homes clean and provides a central location for annual cleaning. Simple and practical.
9.) Too Many Cantilevered Areas
Many newer homes have multiple cantilevers which reduce energy efficiency. These are typically seen on new infill homes, again, on 25 square-foot lots and are used to maximize square footage and add dimension to “boring rectangle” designs. But the home shape that works best in cold climates is a cubic or rectangular shape with the least amount of corners. The amount of gained footage through cantilevered sections is negligible while adding discomfort and heating costs. There are plenty of ways to add depth to buildings without resorting to cantilevers, including using different materials, adding windows, or using art. If you’re not convinced, go to one of your friend’s homes which lots of cantilevers. Stand in one when it is −30˚C outside. Trust me.
10.) Lack of Central Chimney for Cooling
In some ways our homes are difficult to design. Being in northern climates, we have extremely cold winters and extremely hot summers. Our solar insolation swings from extreme abundance to extreme deficiency. For this reason, it’s important to have a central stack, usually designed as a staircase in the centre of the home to allow warm air to rise. If the air has somewhere to go when it heats up, you can evacuate it out on hot days and provide a path for cooler air to enter through means like earth tubes (more on this next post). By using this natural buoyancy, you can bring about fresh circulation without incurring the energy costs of using a fan.
Next up: The Top Appropriate Technologies for Your Home.