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A clinic building under construction in Northeast Portland features a material that stacks like concrete blocks but can be used like wood. In fact, it’s both: a block form made mostly of chipped wood with some cement mixed in.

The blocks, made by Philomath-based ShelterWorks, are called Faswall, and can be stacked without mortar. Interlocking ends hold them in place until concrete is poured into the blocks.

“It’s easier installing,” said Greg Capen, project manager with B&G Builders. “It doesn’t require a skilled mason. And you can use standard woodworking tools.”

A circular saw attachment can cut through the blocks, and nails and screws sink into them without anchors or furring strips.

Using Faswall blocks for the new Larsen Dental Clinic office will cost a little more than traditional wood framing, Capen said, but the owner liked both the environmental benefits of using recycled materials and the sound-deadening properties of the blocks.

Thomas Van Denend, president of ShelterWorks, said the company chips wood pallets, sprays on a mineral slurry and tumbles everything together to form a mineral shell around the wood. The wood pieces are then mixed with cement to form blocks.

The company was founded in November 2006. The Faswall blocks have been used mostly in residential buildings, but are also being used in some commercial projects.

It’s a challenge to use a new product in a commercial setting, Capen said. It ended up costing more because inspectors required more rebar and stronger concrete than the project team believed was necessary.

Architect Francis Dardis with Stack Architecture said the system is plenty strong once concrete is poured into it. “A concrete form wall is only there to fill up with grout,” he said. “You could take all (the blocks) off and still be left with the structure.”

Terry Whitehill, who interprets codes for Portland’s Bureau of Development Services, said inspectors have a responsibility to make sure a new product will work as promised, or as it works elsewhere. “Part of it is you don’t know the durability and the duration,” he said.

Portland’s Alternative Technology Advisory Committee reviews new green products on a case-by-case basis, Whitehill said. Products looking for blanket approval can get International Code Council certification, which allows the product to be used anywhere and specifies its proper use and installation.

Faswall is undergoing a structural analysis at Portland State University, Van Denend said. “It’s a very involved process to do technical testings. We’re at the beginning of that.

“It isn’t like you do a few tests and you’re done and everything’s great,” he said. “Our goal is to bring more data to bear on this and give people more to work with.”

Using recycled wood in concrete blocks isn’t new, Van Denend said. It’s been used in Europe since the 1940s. But its spread has been slow.

As people use the blocks more, and they’re studied more, the process will become smoother, he said.

“Absolutely, I see that getting easier in the future,” he said.