Using 8/4 by10"-22" wide by 8'-10' long pine planks for flooring: Issues?-advice!

[Bill Graham]

Oak,

First of all, welcome to the forum!

Secondly, "DO NOT DO THIS!"

Unless you live in some place like Phoenix or New Orleans where the relative humidity is pretty much the same year round this is not a good idea. The expansion and contraction in pine will leave gaps around the sides or buckle the boards if you install it in dry conditions and cut it tight. I just ran it on the woodshop widget, a 22" piece of flatsawn loblolly pine will vary around 1/2" between RH/temp of 10% and 68F in the winter and 50%/76F in the summer, pretty typical weather conditions for most of the US. I don't imagine your 600 sft. house will have large rooms but there'll probably be at least one room that's 5 boards wide or long. So you're looking at dealing with 2-1/2" of movement or 1-1/4" on each side(assuming it moves equally). That's right at the limit of what you can cover with a 3/4" base and shoe mold, anything doesn't go exactly right and you have a gap at the wall. Maybe if you glue it together and screw it in the center you might have a chance at keeping the movement relatively centered.

And then there's the cupping to deal with: You'll have a finished surface exposed to conditioned air on one side and unfinished surface on the bottom sitting on a vapor barrier. Yes, you can backcut it, screw it down in elongated holes and plug the holes but you're going to a lot of effort to try to keep the wood from doing what it naturally does. Usually the wood wins that fight. And if you do win, you have a polka-dotted floor to live with.

If you can pull it off it'll be a fantastic looking floor but I don't think the odds are in your favor.

Just my thoughts.....

[Oak Ragette]

Interesting, How did you attach them to the sub-floor/joist? From the photo it looks like the boards are not connected to each other, so I assume a good vacuum to pull the dirt out of the cracks is needed, which it sounds like there is no way around that for me, for the width I'm looking to use. Thanks!

[Oak Ragette]

Bob C, I'd be really interested in seeing that picture of the edge if you have the time. Thanks!

[Brian Holcombe]

Assuming these are all flat sawn, why not rip the rift edges off of each board to use and toss the centers? You get the best part of the boards and can still keep them randomized in width.

[Oak Ragette]

Bill G!
Hmm, if I don't do this what do I do with 900 square feet of 10/4 pine?
We live in Hillsborough, NC. We are also building an energy efficient green house so we expect to be controlling the moisture content threw the walls/floor very very tightly. My numbers for expansion came out to almost exactly what yours did, so if I'm willing to solve a 1 1/2 inch gap at the walls with something nifty, then that should not be an issue. The other issue you mentioned is cupping, I plan to have the wood in the house at least 3-4 weeks before laying it down in hopes to reduce the cupping. My main concern is splitting and Mike C mentioned Elastilon which I need to research to see if maybe using that would assist. Thanks!

[Oak Ragette]

Thanks for Elastilon info, I'll definitely research that!

[Oak Ragette]

That is a solution, I was just really hoping to use the full width, some are really beautiful, but from all the feed back it is looking like one of the more viable options. Thanks!

[Andrew Joiner]

Interesting, How did you attach them to the sub-floor/joist? From the photo it looks like the boards are not connected to each other, so I assume a good vacuum to pull the dirt out of the cracks is needed, which it sounds like there is no way around that for me, for the width I'm looking to use. Thanks!

I'm the only one to post a photo so you must be asking me, Oak.

The existing floor was cracked vinyl tile on 4/4 subfloor over 3x14 joists. I was lucky, I wanted a fast cheap solution that was an experiment, but it worked. My floor in the photo was 1x10 #2 Ponderosa Pine with solid knots. I beveled the edges and ends with a trim router just a hair. It was spaced 1/16" apart and face nailed. I used minimal nails shot in at a step angle to keep the pine from moving up. Just enough to hold the boards down flat as I held them with body weight. I mopped on Watco natural danish oil(the formula was different back in the 70's). After a few years the gaps got bigger. It may not work for everyone, but most people would say "these old original floors look beautiful". One loft area was seen on both faces so I selected the best boards for that, but I used no glue and it was a little squeaky. That was my only regret.

In my new contemporary house I used the same thing exposed on both faces in the lofts. I got lucky again as my local lumber yard let me return all the 1x10's I didn't like, including free delivery and pickup! I had twice as much pine delivered than I needed. I selected and placed every board so it could dry in a heated room a few weeks. We have dry summers here so I face nailed with no gaps. I used construction adhesive to prevent squeaks. After 13 years no squeaks and only tiny gaps. I used homemade Watco, equal parts BLO, varnish and thinner on the pine and it's gotten shiny over the years with zero maintenance except constant polishing from socks
As a side note:
Most of the house has exposed concrete floors steel troweled smooth. I researched and tested finishes thoroughly. I didn't want a coating that could not wear off and need recoating. Again I lucked out. I used the same equal parts BLO, varnish and thinner "Danish Oil" on the concrete. The concrete looks like one slab of dark grey polished stone!