Stanev Potts Architects This is Atlantic White Cedar, in a select (vertical grain) grade. We created a custom shiplap detail with an exposed reveal, and the finish was a semi transparent Cabot sealant, in 'natural'. The cedar came from Liberty Cedar in RI:

http://www.libertycedar.com/species-atlanticwhitecedar.htm

I have to say, though, that cedar does of course tend to silver out over time. To keep this looking 'new' the owner will have to apply a bleaching product and then re-apply the 'natural' tone cabot stain.