Fastening 3/4″ wd. flr. over radiant
azreich
| Posted in Construction Techniques on
I will be fastening a 3/4″ wood floor over 3/4″ OSB with a staple up radiant system below the OSB. What is the best and safest option to eliminate the possibility of piercing the radiant tubing? Intuitively, if I nailed only at the joint line I would be okay, but that might not be effective. Is there a staple type fastener that would solve my problem? Someone (I think Jason) mentioned angling the stapler (with a jig) to reduce the chances of tube penetration. All responses are appreciated, Allen
Replies
Shorter nails? Mark the tubing location with chalk lines?
If you are going perpendicular to the joists, you can just mark the joist lines.
If you can pressurize the tubing with air, at least you will know when it gets hit.
I agree with csnow. And if you have any trouble transferring measurements from the tubing below to the floor above, you could drill little holes (3/16"?) to transfer the locations. Obviously not THROUGH the tubing, but maybe consistently 1 inch north of the tubing. One at each end of every straight run. And then one at the apex of every turn. Then chaulk out the floor above. Easiest with two people and a walkie-talkie (or shouting), "This hole is east end of a straight run, now the west end. Apex of turn. West end of next run, etc." The person on top can be chalking as you move the ladder below.
Photo (with an extended tape measure in every shot) the heck out of it or make a diagram on graph for future reference. Say you want to screw some cabinets to the floor or drill a hole to run a phone or cable line. You'll know which areas are clear.David Thomas Overlooking Cook Inlet in Kenai, Alaska
We just put down a bunch of hardwood over a slab with radiant heat within. The slab was sheeted with 3/4" plywood (glued on) and then we did the flooring with staples. I did a scale CAD model to see what the fastener penetration would be. Here it is.
I think your likelihood of piercing a line is extremely small if you use 1-1/2" fasteners.
Allen,
I used 1 1/2" nails with no problem. to make sure take a piece of scrap 3/4" and a couple small boards and do a test, this will tell you just how far the nails go in.
Jason
P/S when I stapled up I stapled to the bottom side of the top I joist, gave me a extra degree of comfort.
You need a tighter nailing schedule than just hitting every joist. Recommended hardwood nailing schedules are usually every 8-10".
That may sound tough to do, but it's quite easy. If your joists are 16" oc, and you have two tubing runs per bay, you should be all set. With the tubing is spaced 8" apart in the bay, the tubing is 4" from the joist and 4" from the centerline of the joist bay. Simply nail off over the joist and halfway between the joists.
That gives you a nailing schedule of 8", which is quite good.
I've surveyed the tubing from below to ensure proper placement within the bay. Wherever the tubing deviates...due to a mechanical obstruction or even at the ends of the runs where they loop...I either drill up through the subfloor and mark a 'no nail' zone as David described, or if the tubing was easily accessible, I've popped the staples at the end loop, stuffed something (usually a small piece of scrap insualtion) between the tubing and the subfloor for clearance, then nailed off, then reset the tubing.
The easier you can make it, ie; the fewer 'no nail zones' you have...especially if you are not doing the nailing yourself...the better. I've seen, and I've done it myself, floorers who get in a zone and nail right through where they're not supposed to nail.
Never had a nasty, but I've swallowed hard a few times.
Safest option? Glue. Second? Short nails that won't exit the OSB. Realize, though, that OSB doesn't hold nails as well as other subfloor materials, so you don't want to sacrifice holding power.
As to nailing at an angle, are you not using a flooring nailer or stapler? Coated flooring staples give great pullout resistance. I absolutely hate having to yank a poorly set staple. Plus, the nailer/stapler sets the angle for somewhat worry-free fastening. As a bonus, the nailing action of a large flooring gun does a great job of snugging the strip flooring together.
Dear Mongo,
It seems that the near fail safe method would be to use a staple that did not penetrate the OSB. I also understand your point about the penetration issue for OSB and the best solution probably being nailing within 4" of the joists.
Can you recommend a stapler and staple size? I've never used a floor nailer or stapler before. Can the angle of the fastener be changed on the gun?
Many Thanks, Allen
Remember, with two tubing runs evenly spaced in each joist bay, the tubing should be about 4" to either side of each joist. If so, I'd look to nail over the joist...maybe slightly off-center so you don't hit any nails/screws in the osb...and in between each pair of joists. Nail 8" on-center.
I wrote nail, think staple as well.
Here's what I use:
http://www.coastaltool.com/cgi-bin/SoftCart.exe/a/bost/bsm111fs.htm?L+coastest+rlmf4761ffcbf2cb+1070447412
It's a fixed angle pneumatic flooring stapler. The only adjustment is for the thickness of the flooring that you're installing. If you choose to nail, rent the nailer instead. Looks the same, just fires nails instead of staples. Tell the rent-all place what thickness flooring you're using and have them make sure that the correct plate is on the bottom of the nailer. Have them show you how to break it down to clear any jammed staples.
Use a 1.5", 1/2" crown staple. Bostich is what I use, they hold well.
It's likely the rent-all place will sell you staples by the sleeve. Buy from them for convenience, or price it out to see if you can save by purchasing in larger quantities from a yard or online. Depends on how big the job is.
Get everything set up and fire several sample staples into a scrap piece of flooring over a scrap piece of OSB. Check penetration on the underside and at the tongue to see how well the crown is set. Try sliding a groove over the tongue to see that they slip together. Adjust the air pressure as required.
Practice a bit and you'll eventually find a comfortable body posture. You'll learn to rock the stapler slightly as you move it along to ensure that it's properly seated before firing. Use the mallet and shoe to set the flooring snug without gaps before firing. The nice thing about these staplers is that they will indeed snug the flooring as they fire, but you don't want to depend on that motion to close a gap between boards. One jammed staple or mis-stapled board will waste several minutes of your time.
Two people working together is great. One to select and set/rack the boards, the other to nail them down.
Avoid the "ppssssssffffff".<g>