(Flickr photo, "Wood Inlay Study" by jlseagull)
Host Intro: You can huff and puff and not blow the house made of straw down…if you use straw based boards. Sueann Ramella reports on building materials that are sustainable in our series, Our Northwest. Listen here.
Sueann Ramella: With the Green Movement there are many products homeowners can choose from that have less impact on the environment and meet their needs. At Washington State University’s Wood Materials and Engineering Laboratory, they have been inventing and experimenting with recycled and wood materials since the 1970s. One product you may be familiar with is composite decking, which is a combination of recycled plastics and wood. But that’s not all this lab has been involved in.
How about building a home using wood strands?
Vick Yadama is an Assistant Professor and Extension Specialist at the lab, and he explains wood strand composites.
Vick Yadama: It’s like shaving a pencil, you know, so you are stranding, taking these flakes or wafers from smaller diameter trees, faster growing trees, and then you can put them together into thick mats such as OSB. What we have done here is we have also said, ‘let’s make thinner plies.’ This is one eight inch strand based plies. They can be used like really thin veneers that are consistent in properties, uniform, very high strength high stiffness and they are pretty.
Ramella: You can use strand based composites for walls, flooring and for decorative purposes.
Another composite material in development is straw based. After harvest, you take the left over straw, split it flat, combine it with an adhesive and make a type of particle board. This material is of particular interest around the Inland Northwest since it could provide farmers with additional income and reduce the amount of stubble to burn. However, availability of the raw material could be an issue.
Yadama: One thing that you need to realize is that the availability of straw is seasonal. You have to think about how to store enough straw so you have a sustained supply of material to make the board. These are some of the challenges that you have to face.
Ramella: Challenges that Karl Englund at the Wood Materials and Engineering Lab says can be worked through if there was demand from customers and if the economics are right.
Karl Englund: Economics has to be there and a lot of time the economics are gonna be there because of the less energy you put into then. If you can balance those two things out, less energy and less money tied into making these products then that’s the holy grail of making these things.
Ramella: The Wood Materials and Engineering Lab is part of the Institute for Sustainable Design at W.S.U. Next week we will talk about a product the institute is working on to replace co2 heavy concrete that you can also compost.
ALTERNATIVES TO PLYWOOD AND OSB (from Pathnet)
Straw Board A structural strength board made from wheat and soybean straw can be used as wall sheathing. Straw boards can be more water-resistant than wood-based panels.
Recyled Paperboard Made from recycled newspapers, paperboard can be used as a sub-floor, sheathing or roof decking. Aside from being very environmentally friendly, paperboard also has a higher insulative value than wood panels and can reduce sounds. Traditionally, it is less expensive than other wood-based sheathings.
Foam Sheathing Foam insulating wall sheathings come in a variety of foam formulations including extruded polystyrene, expanded polystyrene, and polyisocyanurate. Regardless of foam type, however, foam sheathing is the most insulative of all the sheathing options. Foam sheathing does require corner bracing, as it is not structural in nature.
Gypsum Gypsum panels are used under brick veneer, and stucco finishes. An advantage of gypsum is the ability to obtain a fire-rated wall assembly. Gypsum panels, however, must be handled carefully and the paper-faced products need to be sheltered from precipitation.
Cementitious Board Cementitious board is a panel consisting of Portland cement reinforced with fiberglass mesh material. Typically used as backerboard for ceramic tile installations, cement board products have been used as exterior sheathing under a stucco cladding. Not structural in nature, buildings sheathed with cement board must have corner bracing