When building an eco-friendly house, one question that comes to mind immediately is:
which kind of construction materials should I use?
There are a lot of options and a lot of chatter online about this topic.
Unfortunately, a lot of the information you can find when searching is pushed by marketers and it is not really objective (nor true).
In this article, we make the point on what is a TRULY eco-friendly material and how to pick the right ones for your new home.
A (stupid) long list
If you google "list of eco-friendly construction materials", you can gather a good amount of information on which are the possible options.
You should know by now that you cannot trust everything you find on the internet, not without in-depth research.
If you take everything you find for "true", you can build yourself a very stupid list of pseudo-eco-friendly materials.
Take all the information you find with a grain of salt and keep in mind there is a lot of info to find and digest about materials before choosing them to build your own house.
To make your life easier, we compiled a list of the most common (and not silly) materials considered eco-friendly.
Here they come, in alphabetical order:
- cardboard (really???);
- cellulose insulation;
- clay roofing tiles;
- glass wool;
- gypsum boards;
- reclaimed wood;
- recycled cork;
- recycled glass;
- recycled precast concrete;
- sheep wool;
- straw bails;
- stone wool;
- sun-dried bricks;
- wooden chipboards.
Now, here come a few questions:
Are these materials all good to build an eco-friendly house?
Which one should you prefer?
Are there some obvious "no-no-no"?
Spoiler alert: some of these materials should not even be taken into consideration for your house.
Think long term
To answer the 3 questions above, it is important to understand what makes a material eco-friendly.
First of all, we have to think on a longer time-scale than 10-20 years.
In fact, the house you are building will outlive you and at some point, someone will have to tear it down.
For a building to be truly eco-friendly, its demolition and disposal should be considered into its planning... otherwise the building would just be owner-friendly :)
There are basically 3 stages that need to be considered when planning an eco-friendly building:
- sourcing & construction;
- utilization & maintenance;
- demolition & disposal.
A truly eco-friendly material minimizes the use of resources (and money) over all these 3 stages.
Unfortunately, most builders try to push materials that satisfy only the needs of the 1st stage.
These materials are usually cheap and have poor or questionable energy performance.
Savvy home-owners strive to get all the way through the second stage, developing homes that are built with good materials and have excellent energy performance.
...but this does not mean they are easy to dispose of when the time comes.
Most people just don't care about this.
The characteristics of an eco-friendly material
Within the scope of each of the 3 stages, there are a number of characteristics that come into play when choosing the right materials for the build.
Here are the most important ones, listed in order of "importance":
- is the material safe & healthy?
- is the material durable?
- does the material come from a renewable source or from recycled materials?
- is the material available locally?
- is the material energy efficient? (where applicable)
- is the material easy to maintain?
- it the material recyclable or it can be reused/repurposed?
- does the material have embodied energy?
- is the material biodegradable?
To make some clarity on the exact meaning of each of these characteristics, let's see them one by one.
1. Safe & healthy
Something that makes you sick cannot be used as a building material, be it for your home or any other kind of building.
Such materials are obviously NOT eco-friendly and their use should be banned, to begin with.
Unfortunately, there are still materials on the market which contain volatile chemical compounds toxic for humans or that promote the growth of mold.
Do your homework on this topic and avoid them all.
Construction materials must be durable.
There is no point in building anything that won't last at least 2-3 decades.
A construction that decays in a short time cannot be considered eco-friendly.
If you were thinking that cardboard is the material of the future, perhaps you have to think again :)
3. Renewable source or recycled material
For a material to be eco-friendly it is necessary that we are able to keep sourcing it and that doing so does not harm the environment.
When used responsibly, wood is a good example of a material that comes from a renewable resource.
Glass and steel are good examples of materials that can come from recycling... although the processing for their production requires a considerable amount of energy (not the best eco-friendly option).
Sidenote: recycling itself uses energy and resources. Keep this in mind.
4. Local availability
If the material is so uncommon that it has to be ordered from the other side of the world, that's a good sign you are looking in the wrong direction.
Wood, steel, common insulation materials, are reasonably eco-friendly and available worldwide without the need of special shipping (which adds to the carbon footprint of the project).
5. Energy efficiency
Here is where the rubber means the road. Enters stage 2.
Any material used for the building envelope (exterior of the house) must have excellent thermal properties.
In fact, it doesn't make sense using something like "locally sourced, organically grown bamboo" if its energy efficiency is comparable to that of a garden shed.
Don't fall for this trap!
If it does not have EXCELLENT thermal properties, it does not belong in your project.
Sidenote: this is particularly important when looking into insulation materials.
Many look at cellulose, sheep wool, straw bails as viable alternatives...
From a practical point of view, they do not have the same insulation performance of good stone wool and their use introduces more problems than it solves.
6. Ease of maintenance
An eco-friendly material should not cost more in terms of money, energy, materials for its maintenance.
For example: using painted wood in areas with high solar radiation can turn out to be a very bad choice.
In fact, the solar radiation ages paint very quickly and this demands frequent intervention to restore the look and functionality of the exterior finish.
In this case, choosing wood for the facade of the house would not be an eco-friendly decision.
7. Ease of recycling & repurposing
We are now talking about taking the building down. Enters stage 3.
By the time this becomes a necessity, you'll be long gone.
However, the choices you made when you built the house will pay their dividends to your heirs and to the environment.
A truly eco-friendly material can be recycled entirely or repurposed (wood, glass, steel, some plastics, ...).
How eco-friendly you want to be from this point on, is up to you.
8. Embodied energy
This mostly applies to wood, that in the worse case can be burned to supply energy.
That's also a form of recycling, one that does not require processing!
Biodegradability is the capacity of a material to dispose of itself with time.
Not many materials excel in this aspect.
Wood and steel are biodegradable (with very different times) but most commonly used insulation materials are not.
Until humankind will populate the planet, we'll be there to dispose of our own buildings, therefore biodegradability is not super important in the life-cycle of a construction.
Cheaper is better
One rule of thumb we've been preaching for a long time is that whatever material is cheaper is more likely to be more eco-friendly.
This is not always true and there are two exceptions:
- materials that are fundamentally eco-friendly but highly overpriced;
- materials that are super-cheap because they are fundamentally dangerous.
While the second case represents a real threat, the first case can be easily dismissed.
Try to frame it like this: unless you have an unlimited budget, spending more on one particular material will affect your possibility to spend on other parts of the building.
When your choice of eco-friendly wooden floor in recycled cork makes you save on your heating system... you are heading the wrong way.
So, in most cases, when presented 2 choices with a reasonable price, the cheaper one has a better chance of being more eco-friendly.
This is because the price accounts for everything that happened to that material from its sourcing to having it delivered and installed in your home.
Of course, you still need to make sure that the material meets at least the first 6 characteristics described in the section above... and, if you truly care for the environment (and you have budget to spare) also the other 3.
How to choose
Price is indeed a good indicator but it cannot be your only decision metric.
Another important metric is "volume".
You shall prioritize the use of eco-friendly materials for those ones you are going to use the most (in larger quantities).
Structural wood is a good example, followed by high-quality insulation.
In other words, it makes little sense to invest in expensive eco-friendly roof tiles because they are a tiny part of the construction.
Sourcing excellent walls and an excellent roof is instead a smart move... even if it has to be transported from far.
This makes sense because those components are responsible for the energy balance of the building and for its running costs during its entire life.
You want your house to be eco-friendly. That's a smart choice because such kind of home is not a burden for the environment or for your wallet.
We just gave you all the information to you need to make an informed choice about the construction materials to use to pull this off.
We are going to close this article by telling you our favorite picks:
- wood (for the structure, the window frames, the facade);
- Rockwool insulation (recycled and fully recyclable);
- Steel sheets roof covering (fully recyclable);
- gypsum boards for interiors (fully recyclable);
- moisture resistant wooden chipboards (they keep mold out);
- steel, only where structurally necessary (fully recyclable).
We believe than hunting for more exotic solutions is a waste of time and money and it doesn't add anything at all to the eco-friendliness of your home.
Keep it simple. Get it done.
If you want more information or you have any other kind of question, feel free to reach out to us.