[PhillyGuyOldHouse]

Hello

I bought 600 square feet of 5 inch wide pine flooring for my third floor - guest room and small office space. The rooms are currently old tongue & groove over joists subflooring with no finished floor ever installed since 1920.
I was going to install the new pine running perpendicular to the joists over felt paper with an air nailer, then finish with stain and water based clear finish. All of this work was going to be done in the next month or so - I live in Philadelphia, PA. Should I worry about what will happen with this flooring as it expands in higher humidity levels during the spring and summer, or will is stay flat all year? I want to get this project done before Spring and have let the wood acclimate to my house for over 3 weeks... I didn't think that I needed to take moisture readings for the subfloor - any opinions are appreciated.

THANKS!

[KBC]

This is a tricky question.

MOST flooring people will say allow for the expansion and contractions with real wood floors,in a wintertime application I would think this to be especially true.

Maybe have a humidifier running for a week up there to get simulated summertime moisture content?

Also, How thick are the new flooring boards?
Running perpendicular to the old will cause undue stresses to the new where nailed as the old is going to expand and contract opposite to the new.

It would be nice to put this down free floating so as not to have the differing expansions, but I am hard pressed to come up with an answer for that, maybe another will have a response for this.

Hope this helps,

Ken

[PhillyGuyOldHouse]

Thanks - I hadn't thought of the humidifier thing... most flooring products come with directions saying that you need to let the flooring acclimate to the install conditions for a while, which I am doing, but they are getting used to dry wintertime humidity levels. I had thought of leaving a shim between each board as I sink the nails, and then move the shim over for the next run of boards so that there is a little wiggle room for summer movement.

The boards are 3/4 inch thick and will run the SAME direction as the existing tongue and groove subfloor, which is opposite to the joists. One person had told me to glue the boards down with a flexible glue meant for flooring... so many options.