Replies

1. 
   CAGIV | Apr 24, 2003 08:32am | #1

   You just opened a can of worms....

   Screwing is better, nailing will work.

   I'd go 6 oc on the edges 8 oc in the field with 8's ringshanks if you nail.

   Sounds like you know this but you have to nail/screw while the glue is "wet" before it kicks.

   Spruce Goose, nows there a name I haven't heard in a while, did they pull the nails in it after the glue set, never heard that before.

   View ImageGo Jayhawks..............Next Year and daaa. Blues View Image
1. 
   BruceM16 | Apr 24, 2003 06:25pm | #7

   CAG and others

   Thanks for the advice. Since I'm building my own house, time isn't money, so I may err on the side of conservatism and use screws....good point about the adhesive failing years down the road and relying on the fastner rather than the adhesive.

   And yes, they removed all the nails that held the wood in the Spruce Goose...and actually the wood isn't spruce. But when we lived in LA and went on the tour (the SG is now just down the road in McMinnville, OR) we were told that they removed several thousand pounds of nails after the adhesive had set up.

   BruceM

2. 
   AlanMikkelsen | Apr 24, 2003 11:20am | #2

   We glue and staple, with 7/16" x 2" crown staples.

   Alan & Lynette Mikkelsen, Mountain View Farm, est. 1934,  Gardens & Fine Woodworking, St. Ignatius, MT

1. 
   xMikeSmith | Apr 24, 2003 02:22pm | #3

   screwing is for decks, nailing is for sub-floors.. look up the nailing schedule in your code... we glue and nail.. and we've glued and nailed since '75..

   Mike Smith   Rhode Island : Design / Build / Repair / Restore

3. 
   BossHog | Apr 24, 2003 02:58pm | #4

   CAG is right - You really opened up a can of worms. Lots of varying opinions on this subject.

   My opinion is that screws are far better. They pull the plywod down tight, and that forces the glue to spread out. That gives you a better bond. And I think screws squeak less than nails.

   I don't agree that you can take the nails out after the glue has dried. Glue doesn't last forever. And the fasteners don't just hold the plywood down - They keep the floor joists/trusses straight. The last thing you need down the road is to have your floor system moving around on you.

   I was once walking through the forest alone. A tree fell right in front of me -- and I didn't hear it.

4. 
   JDRHI | Apr 24, 2003 03:26pm | #5

   Nail and glue...in combination. There are spots that I may turn to screws in order to assist in sucking the subfloor tight to the joist...but I prefer to nail `em off.

   J. D. Reynolds

   Home Improvements

   "DO IT RIGHT, DO IT ONCE"

5. 
   bill_1010 | Apr 24, 2003 05:10pm | #6

   ONly time you need to screw it down is usually when the silly worker forgot to crown up your joists.

   Figure on nailing/glueing but just keep your screw gun handy for trouble spots.

6. 
   GHR | Apr 24, 2003 06:29pm | #8

   Since your engineer says nails and no glue, you use nails and no glue.

   I design for glue and nails.

   Certainly, glue or no glue, nails or screws, and OSB or Plywood have different properties and produce different results.

   Like others have said - a can of worms.

1. 
   Accelar | Apr 24, 2003 06:46pm | #9

   If you are prepared to incur the additional cost - and glue does eventually dry and crumble and lose adhesion - and nails do squeak - and rigidity / stiffness would be enhanced with screws, why would you NOT use screws ?Gavin Pitchford

    

1. 
   Qtrmeg | Apr 24, 2003 07:32pm | #10

   So when did people start using glue? When did they start using screws?

   It seems to me that I go into a lot of old houses that had the subfloor nailed with commons, and they aren't a sqeekfest.

   I'll continue to glue and nail with ringnails, on the proper pattern my buddy Cag told you about. The glue is insurance, the nails do the work.

   Screw a deck? Nopes, I have better things to do. Oh, by the way, it is a matter of time before these houses have to be taken apart, don't make it a horror.

2. 
   xMikeSmith | Apr 24, 2003 11:48pm | #13

   gavin.. there is no gain.. only loss... our floors don't squeak... they don't move.. and the glue doesn't fail.. so.. extra cost for the screws, extra cost for the labor of screwing.. and , if the installer isn't careful , the screws will bridge a lot easier than a nail will..

   use the time and money to upgrade a different component in your homeMike Smith   Rhode Island : Design / Build / Repair / Restore

1. 
   Accelar | Apr 25, 2003 12:47am | #14

   My home is 112 years old.  Some of the glue they used at different times and renovations has failed.  Some has literally turned to dust.  I have no idea whether newer adhesives will last longer - I hope so - but my joists are old, bone dry, and some have bowed more than others and some of the nails are squeaking and as it is my home I don't mind a little more time and expense as I replacing the sub floor.  Driving a nail into a 112 year old joist simply does not have the same holding or clamping power that nails do.  

   I was genuinely interested in what the down side to screwing might be and there doesn't seem to be one  (beyond cost and time)

   I'm not sure what you mean by "bridging".  Gavin Pitchford

    

1. 
   xMikeSmith | Apr 25, 2003 01:09am | #16

   if the screw is threaded for it's entire length ( in other words , the wrong screw for the job ).... and there is incomplete contact between the subfloor and the joist.. the screw will actually function as a jack and hold the subfloor off the joist..

   a 2d occurence is if the mechanic is unfamiliar with the screw gun .. and there is insufficient contact between the  joist and subfloor.. the screws will NOT pull them together...

   i have never seen sheets being glued and nailed off with the correct nail , at the correct spacing, in the correct sequence.. where the results were unsatisfactory...

   modern construction adhesive will hold  beyond the strength of the two materials it is bonding...

   basically... the question of screwing subfloors seems to be one of opinion.. it is my opinion that a quality floor system doesn't rely on screws to performMike Smith   Rhode Island : Design / Build / Repair / Restore

2. 
   VinceCarbone | Apr 25, 2003 01:04am | #15

   I agree completely with Mike Smith,glue and nail,we use framing guns with 8p nails.3/4" advantex.

   Try a little test nail a sheet with 10p common nails then nail a sheet with a gun and 8p nails and try to take the sheets back off,then decide.Vince Carbone

   Riverside Builders Franklin NY ICQ #47917652

7. 
   GoldenWreckedAngle | Apr 24, 2003 07:34pm | #11

   The screws or nails do a lot more than just hold the decking down. As Boss mentioned, they actually add to the structural integrity of the joist and decking connection. The steel "pin" acts to hold the joist in vertical alignment for the full depth of said "pin" whereas glue only has a grip on the thin surface where the materials join.

   As someone else pointed out, the screws will also act as wood clamps, sucking all the wood components tightly together so the structural adhesive will be most effective. Nails will do the same but not quite as effectively.

   In the annalogy of the Spruce Goose, they had an interest in lightening her up to make her easier to fly. You have no such interest in the home. The only way to get a solid, lasting bond with the adhesive is to tightly clamp both pieces together while the glue is still "active". The only way to effectively clamp decking to joists is with screws or nails. Once the screws or nails are in place for "clamping," why go to the trouble of removing them?

   I would personally go with the screws for the simple reason that they make a better "clamp" but if you are choosing between the nails/screws and the glue- loose the glue.

   Nails will work well, screws will work better. Same with the specified nail spacing. What you have will work but why not over do it a little bit? If it were my house I would go ahead and tighten up the spacing a little.

    

   "One machine can do the work of fifty ordinary men. No machine can do the work of one extraordinary man." -Elbert Hubbard-

8. 
   MikeCallahan | Apr 24, 2003 07:52pm | #12

   Don't make more work for yourself. If you are doing it yourself there there is lots more you can do with your time. With a nailer you can nail off a sheet in less than a minute. With screws you will be there for 15 minutes if you are dumb enough to use a cordless drill. By that time the glue may have skinned and you will have squeaks. Time is of the essence when laying subfloor. Adhesive does not get brittle as some others said. There are many amatuers with little experiance that are freely dispensing advice on this forum. I have layed many square miles of subfloor in the last 40 years and I have NEVER used screws. If your joists are dry and you nail the floor right away when the adhesive is wet then the bond should last the life of the house. I am surprised the engineer specced 12d nails. They are 3.25" long. TJI and 7/8" flooring would be max thickness of about 3" and the nails would blow through. Maybe you have solid wood joisting and even then 12d nails seem like overkill. 8d ringshank would be fine. 10" would be enough for field nailing but nail at least 6" on the edges. Check for shiners underneath right away before the glue dries. Don't lay OSB tight either. 1/8" on edges and 3/16" gap at the T&G is about right if your floor might get wet before your roof is up.

   We may be slow, But we're expensive.
1. 
   BruceM16 | Apr 25, 2003 03:56am | #18

   Myci (and others)

   Thanks for the detailed info. What is a 'shiner'?

   One other question....do you lay the 4X8 sheets perpendicular to the direction of the TJI's or longwise? Logic suggests the former....but if done longwise there will be half as many unsupported T&G joints.

   BruceM

1. 
   JohnSprung | Apr 25, 2003 04:23am | #19

   > What is a 'shiner'?

   It's a nail that misses the joist.  You see the shiny new metal sticking down when you look from below.  One downside to pneumatic nailers is that they make it easy to put in a whole row of shiners and not know it.  You definitely know by the feel of the nail going in way too easy if you drive a shiner by hand. 

   As to screws vs. nails:  It depends on a lot of things.  Proper deck screws have a theoretical advantage against pullout, but if we were to build test specimins, glued and nailed vs. glued and screwed vs. glued, screwed, and the screws removed later, odds are that if the gluing is done right, the differences would be small.  I bet Howard Hughes tested that one thoroughly before they built the Goose.  Glue some two by to some ply with good aliphatic resin glue, and break the sample a couple days later.  You'll find that the wood breaks, not the glue.  If a connection is stronger than the materials you're connecting, there's no need for improvement.

   -- J.S.

2. 
   bd342 | Apr 25, 2003 04:26am | #20

   listen well to what mike is saying.

   it matches exactly to my own experience.

2. 
   Nails | Apr 25, 2003 04:37pm | #21

   My."Don't lay OSB tight either 1/8" on edges......"  Here I go again , the house is 64 ft long . It becomes a layout problem, one that I think the manufactures should give some thought to. Yes I go back and use a thin kerf blade to allow for expansion , it only took one sub floor that was exposed to weather and a belt sander to convince me.

9. 
   stossel1 | Apr 25, 2003 02:57am | #17

   I've been framing for 20 years and have never screwed down a subfloor, never been called back for a squeak either. Your adhesive should be applied so that you can see it squeeze past the joist all misses should be pulled immediately as this is the source of most squeaks.