March Topic and Key Point
Foundations to Roofs: Structural and Exterior Green Materials
March 21, 2006
(Click on the panelist's names to jump to their key points below.)
A panel of green building professionals discussed the key issues of different green exterior and structural materials. The panel covered green materials by Jonathan Bean of Environmental Building Supply, structures by architect Dave Wadley, roofing by John Nicol, and windows & doors by Mark Bell of Classic Sash & Door.
Afterward people broke into small groups to ask questions and talk with one another in more detail about the topic.
Key Points
Here's what our panelists think people should know about green materials for home interiors.
Green Materials
Jonathan Bean
Director, Marketing & Product Development
Environmental Building Supplies, www.ecohaus.com
503-222-3881, info@ecohaus.com
3 key points to consider in selecting materials:
1. How much do you need?
House sizes have doubled since the 1950's and each American, on average, now takes up 800 square feet of conditioned interior space. You can happily live in less -- many people do. Can better design take the place of more space? When you build less, there's an initial savings -- a smaller house needs less siding, less roofing, and less labor than a bigger house. But there's also a long-term savings: less paint (and less off gassing in the long run) and less energy. How green a product is doesn't matter if you're using more of it than you need! Make a conscious choice to spend money on quality rather than quantity.
2. What does green mean to you?
Some people think indoor air quality; some, energy efficiency; some, recycled materials; some, local materials. There are other criteria, like natural content, water conservation, and embodied energy. You can't build a house
that fits everyone's definition of green; there is always some balancing involved. Take some time to make a list of your core priorities and share it with your architect, designer, contractor, and the salespeople who help you find the products that will go in
your home. Take green certifications with a grain of salt -- some, like FSC, are the real deal. Others are meaningless fronts for industry interests.
3. Distinguish between one-time costs and ongoing demands.
Based on the list of priorities you developed, you can answer questions of value like the following. Is the petrochemical content of vinyl worth it if it means lower energy use, or are there other ways to reach the same objective? If a natural floor covering will last 40 years, and synthetic only 10, how much more does it make sense to spend? Often the green choice will be less expensive if you look at it over time.
4. The exterior and structural materials that people should be looking at now include:
- Natural hydraulic lime plaster, for durable, natural-looking interior and exterior surfaces.
- Locally grown wood from the Healthy Forests, Healthy Communities partnership -- which integrates social and environmental goals with the wood products industry.
- Cotton insulation -- made from denim scraps.
- Natural paints and finishes like mineral paint for lime plaster or plant-based Wood Glaze that are more durable or better looking than synthetic alternatives.
Structures
David F. Wadley
design, planning, research and construction contracting
503-543-2154, Archexpand@earthlink.net
1. Misconceptions may include:
That style is more important than other substantial matters, that wood framing is the only way to build, that we do not have materials to drasticly improve building performance at this time, and that we can make only small changes to the way buildings are thought of and built.
2. Some materials that I am considering or working with:
Aerated Autoclaved Concrete units, perlite, pumice, Apex blocks, Rastra blocks, lime plasters, earthen plasters, cob, local stone, recycled wood, solar shingles, solar siding, glass, eco roofs and metal.
3. Resources available include:
Developing your own understanding is most important (thinking about various aspects). I would recommend talking to many different designers, builders, architects and books before you start to form too much opinion. Few written works really stand out for me, maybe because after reading 8,000 books in the subjects they all merge. I like to think about things and learn from what does and doesn't work in everday life observation. I have been influenced by Ianto Evans, his cob and rocket/lorena stove work. Christopher Alexander and Pattern Languages. Several theoretical writers from Europe have pondered new ides for years.
Roofing
John Nicol
503-236-5997, jnicolpdx@yahoo.com
1. The modern roof is two roofs: the primary roof and the secondary roof.
The primary roof is the one you see, the one which protects us from sun, wind, rain and snow. The secondary roof, also called an underlayment, is a temporary roof to protect the house until the primary roof is completely installed and is also a back-up roof when
the primary roof fails and begins to leak. The norm in the United States for the residential primary roof is the asphalt composition roof, with a life-span of 20 to 35 years. The norm for the secondary roof is #15 and #30 building felt. Few Americans see beyond these products if they think of the roof at all, and a huge industry has evolved to produce and install them. We have accepted a temporary roof as our norm.
2. Alternatives to the modern American roof are evolving or are being imported.
Europeans have never thought of their roofs as temporary. Years ago, I was informed by an English architect that the American asphalt composition roof was prohibited by law in England. Europeans developed alternatives to our building felt secondary roof decades ago, called synthetic or high-performance roof underlayments, and these are now available to us. They will not rot, tear or quickly disintegrate in the sun. I have identified seven of them. The modern primary roof is in evolution. Heat-reflective undercoats have been developed for metal roof finishes. Experiments with recycled plastic and rubber and with Portland cement, some of them disastrous, have given us some good new primary roofs.
3. The secret to choosing a sustainable roof is in your criteria.
What will you accept for the life of your roof? Without a roof, you don't have a house. The roof is the house. Europeans consider a 100-year roof acceptable. War, occupation, plagues, and economic slavery have taught them that. Under those conditions, few can replace a roof. How well does a roof product handle wind? Fire? The early recycling
experiments with plastic and rubber did not have a Class A fire rating. Can you walk on it without damaging it? What does it weigh? The lighter the roof, the less structural support is required. Is it appropriate to your climate? A heat-reflective undercoat may not allow snow to melt off the roof in some climates. Are its components compatible and do they have the same life span? This is an issue with photovoltaic shingles. Selecting the right roof is the most important thing that you can do for your house.
Windows & Doors
Mark Bell
Owner & President: Classic Sash & Door Company, www.classicsash.com
mbell@classicsash.com
1. Define what is important about the windows and doors for your project:
- Will there role be to provide energy efficiency, light and ventilation only?
- Will the exterior architectural design be impacted by the windows and doors?
- What about the interior design impact?
- How long will you live in the home?
2. What is available today in the window and door market place and how Green are they?
- Vinyl
- Fiberglass
- Wood
- Wood Clad
- Composite
3. What are the benefits and drawbacks to each type of materal.