This calculator is a simple way to explore how long building materials last and how long they take to renew. It helps architects, builders and designers to choose materials with better information.

How it Works

The calculator uses two sets of data:

• Elements Data: This file lists building elements, which are the parts of a building. They are grouped using the SfB classification system, a standard way to sort building parts. For each element it gives a typical lifespan in years. It also gives how long different materials could last when used in that element.
• Materials Data: This file lists materials, mostly types of wood. It gives the typical time a material takes to renew. For wood, that is the time a tree takes to grow big enough to harvest.

The sum is a simple ratio. A ratio divides one number by another:

Use/Renewal Ratio = Lifespan of Material in Element / Renewal Time of Material

A higher ratio means the material lasts much longer than it takes to renew. This is generally a good sign for sustainability.