When digging the foundation, we hit a ledge and were left with two choices—either blast through the ledge, or deal with what we found. We opted for the second in order to minimize energy consumption and preserve the integrity of the land. Because we could not dig as deep as we had planned, we can stand up only in half of our basement, leaving us with less usable basement space than we had hoped. At the time we felt the compromise was worth it.
Our foundation is built of dry laid stone, a natural material that we didn’t even need to transport—we simply collected the stones from a stone wall that ran through the woods of our property. We chose a dry laid stone foundation because it wicks less moisture up from the ground and allows air to circulate under the house; this helps keep the plastered straw bale walls and timbers dry and less prone to rot. With a dry laid stone foundation, there is an even greater need for insulation under the first floor. We felt this was a small price to pay for creating a beautiful, breathable, bale-friendly foundation.
Several steps were taken to further protect against moisture problems in the basement. A copper drip edge was installed along the bottom of the exterior walls to channel rainwater away from building’s base. We also covered the basement floor with 4 feet of gravel so that any moisture that did get in would flow down rather than sit on the basement floor. Finally, we installed windows in the basement so that we could keep the fresh air flowing in, at least during the warmer months. After 13 years and despite some heavy spring rains, we still haven’t had any major problems with moisture, mold, or mildew in our basement. After 13 years, however, the lack of storage had become a problem and we are looking forward to using the basement in our new building. Our new basement houses our renewable energy equipment along with a water tank and other household equipment. There is also storage space and some garage space that can be used for cars in times of snow or for workshop space.
Having lived without a basement for 13 years we are hoping this new space will help us to keep better track of our tools and bicycles, rather than encourage us to fill it up with lots of junk we don’t need- a common problem when one has extra space!
The building of the basement was a real eye opener. Weatherproof basements are a modern phenomenon and the creation of weatherproof basements necessitates the use of modern building materials. It was with much chagrin that we witnessed the pouring of a concrete foundation and basement walls. While we specified a high fly ash concrete, and a less toxic “form release agent” to replace the commonly used diesel fuel, the effects of concrete production and transportation are still unpleasant and we are sorry to be part of that cycle.
It was with even greater unhappiness that we watched as several panels of foam insulation were attached to the concrete walls. We looked into other forms of insulation for this below grade application including mineral wools that are apparently common in Canada. Unfortunately we were unable to locate a product that we could get locally that would do the work as efficiently as the ubiquitous “pink board”.
With this new building we have entered the realm of “modern construction” far more than we did in our first structure. Like a hospital visit that leads to ever greater complications, modern building’s methods and materials build on each other and before you know it you are surrounded by concrete, foam and plastic. While there are less-toxic alternatives, it will be nice when all current modern building materials can have truly “green” substitutes.