Green Roofing Resource
Roofing is a very important consideration in home building. It helps control the flow of air and moisture into the home and also insulates the home from extremes in temperatures. It is very climate specific and will provide years of service when installed correctly
See Chapter 6 on Roofing in the Green from the Ground Up book for more details or contact us about training.
What is a Green Roof?
Some roofs are literally green. Live vegetation can take the place of shingles, tile, or sheet metal. But one of the most important considerations for a sustainably built house is durability. The longer the roof lasts, the greener it is.
Green Roofers’ Transition Guide
Use long life (40-50 year) shingles
Shingles are a petroleum based product, require a lot of energy to manufacture, and should be installed to last as long as possible.
Long life shingles will save the homeowner money on replacement and repair costs
These shingles are available from most manufactures
Specify recycled content materials
- Recycled content asphalt shingles contain recycled waste paper and/or use reclaimed slag material in their aggregate surfaces.
- Discarded asphalt shingles are a major source of construction waste. Roofers should help keep them out of landfills by recycling them
Install concrete or clay tiles
Concrete or clay tiles are very hardy. They last a lifetime and require minimal maintenance in mild climates.
Check with a structural engineer to verify that the home can support this additional weight.
These roofing materials take more skill to install and cost more than asphalt shingles. Be aware that they can shatter in hail-prone areas
Install metal roofing
Metal roofing has a long life, its fire resistance and is highly reflectivity in light colors.
If available, install metal roofing with recycled content. Make sure it has no lead content.
More expensive than asphalt shingles, but a great green product as it can recycled at the end of its life.
Frame with Trusses
A raised-heel truss has added room at the eaves for insulation, good insurance against ice dams.
Substituting I-joists for wide dimensional lumber is a smart use of wood resources. I-joists provide equal or superior performance using less wood fiber and relieve pressure on remaining forest of big trees.
Use light color roofing to reflect summer sun
- Light colored roofing reflects, rather than absorbs, heat from the sun. The result is a cooler home and reduced cooling bills.
- It lasts longer because it doesn’t expand and contract as much as dark colors.
- Check the Solar Reflectivity Index ratios (SRI) to see how well a product will reflect the sun.
Avoid flat roofs
Most flat roofing products are petroleum based, require a lot of energy to manufacture and install, and they have a relatively short life span.
A steep pitch discourages standing water, leakage, ice dams, and heavy snow buildup.
If you cannot avoid installing a flat roof, make sure to use materials that that don’t release odors and fumes. It should also be coated with light-colored or reflective pain
Green Building Training & Certification
Find out when the next Green Building Training is and learn more about Green Building Practices.
Read more on the Federal Tax Credits for Roofing
- Metal Roofs, Asphalt Roofs ENERGY STAR qualified
- 30% of cost, up to $1,500
- All ENERGY STAR labeled metal and asphalt roofs qualify for the tax credit.
- Must be expected to last 5 years OR have a 2 year warranty.
Green from the Ground Up Best Practices
- Use raised-heal trusses. If framing the room with dimensional lumber, install a rafter plate to allow sufficient insulation at the eaves.
- In a cooling climate, use radiant-barrier roof sheathing.
- If ductwork runs through the attic, treat the attic as conditioned space by insulating both the rafters and the ceiling.
- Choose the most durable roofing material available that’s appropriate to the climate. Avoid copper and galvanized metal roofing as well as inexpensive asphalt shingles.
- In cold-weater regions, protect the lower 3ft. of the roof and valleys with a self-adhering bituminous membrane.
- Install an effective air barrier between any ceiling and unconditioned attic. Seal any penetrations.