Some questions on wood floor underlayment, etc.

[Ellis]

Hi,
I'm going to put down a pine floor in my entry room. I've pulled the carpet and all the old layers that were under that (partical board, linoleum, plywood, two more layers of linoleum, and a layer of newspaper from 1915(!)).
I'd like to put a layer of backerboard such as HardiBacker to bring the floor level back up close to where the carpet was. Should there be a layer of something else between the sub-floor and the backerboard? I've heard of people using tar paper, resin (rosin?) paper, or roofing felt. What do people recommend? Also, should there be a similar layer of some sort of paper material between the pine boards and the backerboard?
Lastly, the pine boards I'm using are salvaged high-school gymnasium bleacher boards. They're 3/4" thick, 7 1/2" wide, and between 14' and 18' long. They are not t&g. I suppose i could route a notch in the sides so that they overlap a 1/2" or so if it was really important. Otherwise I'll just leave the edges of boards straight. I'm thinking that I'll just use screws to fasten the boards to the sub-floor, going from one side of the rom to the other, laying each board and fastening them one at a time. Any general advise or warnings here?
Thanks for any help.

[mrcaptainbob]

Not sure about the underlayment portion, but as for the laying together of those pine boards.....I'd use a biscuit joiner and biscuit them every six inches. There are hammer operated nailers for setting flooring that drives the nails at an angle into the edge of the boards so they're hidden. After you set the first board down with that nailer, do the biscuits in between the nails. Apply your wood glue and set the next piece in place. It sounds like that floor will look great, and should stand up to wear for a long time!

[HayZee518]

I would think the floor boards would buckle with the use of biscuits. I know when I edge glue wide boards together, applying tension with clamps tend to push the boards upward. If you have the means to cut a tongue and groove in the edges, it would make nore sense in using this type of joint in that you can nail at an angle through the groove and keep the nail heads hidden. www.rockler.com has a tongue and groove cutter for a 1/4 inch and 1/2 inch shank router.

[PlumBob]

I'd agree w/ HayZee. Edge joining is a real pain.

I'd do lap joints, or tongue and groove, and nail as w/ any standard hardwood plank floor installation.

PlumBob

[mrcaptainbob]

Okay. I agree with that. But then it occurs to me....how were those, (or any basketball flooring) held in place?

[PlumBob]

Huge caveat, Cap'nBob, I've never done this.....

But my understanding is that, take tongue & groove for instance, each plank is nailed in individually, w/ a nail going into the edge and from there into the sub-flooring. When set, the nail is set into the edge of the plank, and not the top. The nail actually goes in at an angle: 1) to get a bigger bite of the flooring plank, 2) so that the process of setting it into the subflooring pulls it up tight against the plank preceeding it, 3) that the angled nail has more holding power into the subfloor, than a nail straight up and down would have, and finally, 4) there's no nail-head to see (or catch your sock on).

The tongue (or groove) holds one side of the plank, the nail holds the other. In retrospect, I suppose a biscuit would serve the same purpose as a t-n-g.

They make nailers that allow you to pop the nail into the edge of the plank, at an angle, and then the same hammer-blow snugs the plank up next to the one before it.

Again, that's my understanding of something I've never done!

PlumBob

[LazyPup]

When tongue and grooved flooring is laid with the flooring nailer the boards only get nails on one side of the board, they are loosely fit into the grove on the other side. By securing them in that fasion the boards are individually locked in place while the opposite side of the board is still free to float a bit in the groove to allow for expansion from humidity.

[PlumBob]

LP, have you ever actually done this? Use a flooring nailer, that is? I've considered it, but just never quite gotten there.

PlumBob

[HayZee518]

I've used a flooring nailer when I was putting in a maple floor in one of my houses. They're sort of cut nails in a strip that's loaded staple style in the nailer. The shoe fits the edge of the board then you whack the rubber cap on it with a stout mallet. One shot it's done! But they now have pneumatic nailers.

[mrcaptainbob]

Yeah, PlumBob, I go along with the way t & g is applied, but in your post you said it was not t & g. That's why the question. If it's not t and g, then what manner of attachement is used? Or, since it's reclaimed, does that mean the edges were (the t and g's) were cut off?