Swale and Berm in Natural Building
Its been a long time since we posted on the site. Sorry about that. Between the Holidays and moving, we have been also trying to work on our new house. Lots of work , we needed a loft for sleeping, a bathroom, a kitchen, hot water heater, and some storage. So far we have 3 out of 5, more to do. We also don’t have internet, so we have been using our cell phone as our internet. Makes it a bit hard to post. But we are all happy, exited for the new possibilities at our new location, and we have overcome many obstacles to bring you the next step on your way to building your Natural Building.
So lets recap; you have laid out your building lines and you have removed the top soil, now you are ready to start digging out your swale and building up your berm around your building site.
The first thing you will need to do is look at the lay of the land. Where are the high spots? When it rains, which way does the water go? Will it want to go through your building site?
What we do is look at the contour of the site. If the land is sloped towards the building then we want to make sure that the rain water will not flow into the building. The way we do this is by creating a swale for the water to flow in and around the building.
The other way to help water flow into the swale instead of towards your building is to create a berm. In most cases your swale will be next to your berm, as illustrated in the picture below.
The other part to consider when creating your swale and berm is the roof line. You will want to make sure that any rain water that comes off your roof will have a place to go, and flow out and away from your building.
Taking all of these things into consideration you will want to make sure that your swale slopes from the high side of your building site down and away from your building. Depending on how much rainfall you get per year, you may want to dig the swale at least 18 inches wide and three inches deep at the lowest point of your swale. You will also want your berm to be at least three to six inches higher then the ground level/finished grade depending on your site.
As you begin to dig out your swale, you will start at the high side of your site, and will want to make sure you are sloping at least 1 inch every 4 feet towards your low side, or 1/4 inch per foot. In some cases your site may have a natural slope so you could just follow it, and just check every once in a while to make sure it’s sloping at least 1/4 inch per foot.
Once your swale and berm are dug out you will want to protect it so it doesn’t get re-filled or trampled during the building process. We usually put a few boards over the swale so people can walk over them to the building site.
In almost all cases, we make sure that the swale and berm go all the way around the building, making a circle around the site. This way we protect the building on all sides in case rain water finds a way towards the building.
Stay tune, next is the Ruble Trench Foundation, favored by Frank Lloyd Wright.