Hi,

I live in MN. I've built a nice 18x14 deck that's enclosed with roof and very large EZE Breeze windows on 3 sides. There should be no elements that get in but it will experience wide fluctuations in temperature and humidity with the change in season. It gets sun from 9am till 1pm daily. I have bought and placed reclaimed barn wood planks in the structure to acclimate since October 20th. The planks are 3/4 inch thick tongue and groove that range in width 8", 6" and 4". I will be installing over a 3/4 inch treated tongue and groove plywood floor.

I appreciate the worn and old imperfections of the wide plank barn wood and believe some of the gaps or spacing will only add to the character. The biggest concern would be cupping.

I have read many different opinions on how to install and finish reclaimed wood but none seem to apply to my situation. Can someone please advise me as to whether to use asphalt paper, to glue/nail/float/combination, whether to sand and how, and how to treat it.

I wish I could attach a picture. It looks great and I really want to install this the right way. Any advice is greatly appreciated.

Thanks, Minnesota Joe

It's recommended that planks wider than 5" be glued, since they will only be nailed on one edge, the nails will be far apart. You can use moisture cure poly-urethane for the glue, or latex sub-floor adhesive, either as a full trowel or beads across the planks every foot as they are laid, so any paper under the floor is out.
I would use galvanized floor staples every 6 " and also at the ends of planks that are accessible, even though there is no tongue.
I think that sanding with a 50 grit random orbit hand sander to take off very rough spots the with 80 grit should be fine for most finishes.
I recommend a pigmented oil finish in a brown color like what would be the color if it was left alone, not too dark, for exterior wood surfaces, which will give better UV resistance in the long term. This will also anchor the architecture so the floor seems solid.
The over-wood will show wear earliest and oil can be re-applied over clean flooring after wear takes place to keep a nice glow on the floor after it has been lived on over time.

Thanks very much for your time and advice!

We feel like we're in the right direction now. I might check back in after we start testing the oil finish on left over boards.

Good luck to you.