Builders have sustainable options available to them if they’re willing to think outside the box. Here are our top five sustainable building materials you should try incorporating into your next project.

1. Bamboo

Bamboo is one of the most sustainable building materials available for a few reasons. First, bamboo is the fastest growing plant which can be used as a building material. In many regions it grows quickly in the wild without any human intervention—sometimes so much so that it’s considered bothersome or treated like a weed. People often think of bamboo as a tree-like plant, but it’s actually a grass. It spreads on its own like grasses do. This fact increases its sustainability factor over that of lumber from trees. Trees typically must be replanted after harvesting; grasses grow back (and spread) on their own.

In addition, bamboo’s highly compressive strength and versatility make the plant a go-to for various construction projects. Pro Tip: Building experts caution that bamboo must be thoroughly treated before being used in construction, because in its natural state it’s susceptible to insect damage and rotting.

2. Timber

Timber gets a bad rap: as soon as you hear the word, you may envision pollution-spewing machines clear-cutting a forest. In actuality, when wood is harvested using maintainable environmental practices, it is one of the more sustainable building resources available. Pine trees in particular tend to be a good choice when you are looking to utilize wood in your building projects, as these typically grow more quickly than other types of trees.

Our main point here: don’t discount lumber when seeking to build sustainably. When sourced properly, lumber is a renewable resource that offers a lot of value.

3. Reclaimed Wood and Metal

Metals aren’t renewable, so on their own they aren’t particularly sustainable. Earth will, eventually, run out of metals to mine. And, as already mentioned, not all timber harvesting operations are sustainable. Despite this, you can build sustainably using wood and metal by choosing reclaimed or recycled materials.

Using reclaimed materials is one of the most sustainable and earth-friendly ways to build. These materials have already been harvested or mined. If not reclaimed, they will end up in a landfill eventually. By repurposing them for your building project, you give the materials a second chance at usefulness. More importantly, by utilizing reclaimed materials, you are keeping more metal in the ground and avoiding the harvesting of trees.

4. Straw and Wool

Straw and wool are both sustainable, of course, but they probably don’t come to mind immediately as building materials. True, you’re probably not going to build a roof or walls out of wool, but both these materials are excellent alternatives to synthetic insulation products. They can be used in place of fiber or foam insulation to insulate walls and attics.

There’s also a movement to use straw for more than just insulation. The Last Straw is an organization dedicated to straw bale and other natural building techniques. Straw bale construction brings an ancient construction method into the modern era. This technique involves building a frame which holds sealed straw bales, providing a completely natural alternative to concrete or drywall construction.

5. Concrete

Concrete has a strong industrial look, and it’s ubiquitous in modern construction. These facts might lead you to assume it’s dirty, unsustainable or bad for the planet. Actually, the reverse is true: concrete is considered a sustainable material.

Why? The Concrete Network notes numerous reasons. For starters, concrete’s main ingredient is limestone, which is the most abundant mineral on earth. Concrete can also be made from certain industrial waste products, including fly ash, slag cement, and silica fumes. Turning these waste products into a quality, durable building material saves them from going into a landfill.

Buildings made from concrete don’t rot, decay, or burn, and they often last more than twice as long as buildings built from the other popular building materials. When a concrete structure does eventually reach the end of its life, the concrete doesn’t go to waste, either. It can be crushed and recycled into materials which can be used in other applications, including concrete pavement, backfill or road base. Concrete is very strong, relatively inexpensive, and sustainable. No wonder it’s so popular.

There’s no perfect building material and construction comes at a certain cost, but using these top five sustainable products can dramatically lessen the impact of new construction on the environment. The next time you are planning a remodel or addition to your home, keep sustainability in mind. Be kind; build sustainably!