Yes, I believe the flooring they used was fir--but not sure of the wood size--maybe 3x5. We've just finished the first part of this project using old fir beams; however, they are 4x8. Finally got everything cut and glued down.
Now for the hard part. As per the instructions on the Bob V. video, we mixed sawdust, 2 parts to 1 part oil-based sealer, and troweled it in between the "bricks." Well, guess what--the sealer does absolutely nothing but soak right through the sawdust--there is no "stickiness" at all. This is not the right recipe. So, a warning to everyone who is thinking of trying this. I talked with some floor professionals in my area. Two of them laughed, and one of them said the idea that sawdust and sealer would adhere to ANYTHING was "stupid." By golly, I believe he's right!
Now, with just a light sweeping, I'm getting dustpans full of sawdust! YIKES! What are we gonna do! One guy suggested that we vacuum all the sawdust out and start over--this time using a product called "Wood Putty" which is MADE to be mixed with sawdust. Hmmmm--wonder why Bob did not provide that info. All I know is, we've got a whole lot of work ahead of us, unless we can come up with some innovative idea!
So far, the only help I've received from the Chicago website of the guy who supposedly invented this technique brings nothing but an offer of the mastic stuff at about $50 a gallon. I'm sure we'd need 10 gallons. Can't do it. I just wish they'd share what the secret ingredient is that was left out of the video!