A Primer For Choosing The Right Roof
by Chris Keefe
In the world of designing a home, especially for a straw bale house as you’ll see, the time comes when you have to choose an appropriate hat to place upon the house. There are many options and combinations of options to choose from so for the sake of this being a simple primer, we will go over some of the most popular ones used, and some advantages and disadvantages of each option along with an example or two of when it is a good idea to use it.
The first roof is the shed roof. Shed roofs are basically a flat roof that slopes in a single direction from one side of the house to the other. The advantages of shed roofs are they are very easy to build, and therefore keep the cost down. They also provide a good opportunity for clerestory windows to bring light into the interior, as the downward sloped roof can protect the house from excessive sun or moisture. Disadvantages include the fact that it is not very exciting to look at. It also tends to leave the “high” side of the house vulnerable to the elements. For straw bale this can pose a problem in keeping the walls free from direct moisture. A good time to use this roof is obviously when the budget is tight or if you want a larger exposed side of the structure as in a greenhouse, or in cooler climates.
A gable roof is probably the most popular and traditional roof. It is the basic triangle roof or two shed roofs that meet in a point at the top and bear down on two sides of the house. Some advantages of the gable include, again, the relative ease to build. This roof is also a relatively economical alternative in the overall choices out there. Additionally, it provides a good opportunity for a 1-1/2 story structure that offers a loft or second story that presents a unique feel with slanted walls and possible dormers to bring in light and offer nice views. A disadvantage of the roof is that it leaves two sides of the house vulnerable to rain, with the little or no overhang, and direct sun, if there is glazing on those sides. A good remedy for this is to build a trellis structure to protect glazing from the direct sun or a smaller gable beneath the main roof that overhangs the majority of the exposed wall thereby giving it more protection.
The hip roof is a roof that slopes down toward all sides of the building, and therefore bears its load upon all of those sides. Coupled with adequate overhangs this provides incredible protection from rain, to keep all of the walls dry, and from the sun, to protect the glazing from direct exposure when it is undesirable. For this, it is often a very good choice for straw bale homes. Additionally it tends to be the best choice to resist high wind loads. A disadvantage of the hip roof is that they tend to be a bit more expensive to design and build, but there are strategies out there to help keep the costs down. Hip roofs grant great protection from the elements, so anytime when there are extremes in elements, the hip is a good way to go.
Flat roofs or parapet roofs are yet another alternative and tend to be popular in the warmer climates. These roofs, which are not really flat, have a slight slope to help shed water. Some advantages include: they are relatively economical and easy to build and they afford patio space on top that can have simple sun protection and be quite a comfortable space in warmer periods of the year. Some disadvantages include: A good design and attention to detail during construction are an absolute must, as these roofs tend to leak, especially during extended periods of rainfall. Regular maintenance is necessary especially if there a fair amount of foot traffic. A good time to use this style is, as stated before, in warmer climates with low rain and snowfall.
Living roofs are becoming more and more a viable alternative in roofing choices. Living roofs range vastly from modestly simple to intricately complex. Typically they consist of a slightly sloped plain with ample support beams, sufficient waterproofing and soil with, preferably, native grasses and vegetation on top. Advantages include very obviously, the natural beauty they impart especially when coupled with the organic nature of straw bale. They also, if done properly, will require little to no maintenance. As stated before if native grasses and plants are used, the roof itself will be just an extension of the independent nature of the surrounding ecosystem. They also provide incredible insulation. Disadvantages include as mentioned in the flat roofs, much attention is required in the design and construction to insure proper shedding of water, and if in a high rain or snow climate, thought must be given to the structure to handle those kinds of loads. Living roofs are great for smaller structures as well as larger ones. It is an ideal way to connect your building intimately with its surroundings.
So there you have it, five of the most popular hats for your building. There are many more out there, domes, vaults, and various combinations of all of the above. As a designer it is an exciting process, choosing the roof style to complete your design. Whether it is all about budget, protection, style, function, or even envelope pushing, Take time to choose a roof that suits your building. It’ll thank you for it!
ABOUT THE AUTHOR
Chris Keefe, from an early age, discovered his creative spirit in art. In 1996, he received a B.A. in Liberal Arts focusing on drawing, Music and Philosophy from San Francisco State University. In tandem, he was actively involved in a grassroots environmental project for five years at the University of California in Berkeley. He became interested in the field of straw bale as he began his graduate studies in 1999 at the San Francisco Institute of Architecture. Focusing to integrate his work in the environmental and sustainability field with his creative imagination, he received a Master of Architecture and Ecological Design in 2001. In 2002, he founded a company called OrganicForms Design, which offers cutting edge straw bale design plans and other ecologically minded design modes. He has worked extensively researching and developing a system of plans that bridge the gap between conventional construction and straw bale construction. He has completed over 40 straw bale home designs in 15 states, 2 provences, and Europe. For a look at his completed work, please visit his web site at www.OrganicFormsDesign.com
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