Replies

1. 
   david_thodal | Dec 22, 2001 07:52pm | #1

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   Greg, Never tried it with 3/8" plywood. The thinest I have used is 1/2". Should be okay if your sub-surface is flat. I like to lay the first course completely before I start the second course. I off-set all my joints, both length and width. I like Ener-bond Urethane foam adhesive for between the sheets of cdx. Screwing may be a problem, achieving a flush screw set with only 3/8 cdx. That was a problem I had using 1/2". But I was over concrete and not foam so maybe it won't be an issue. I find I can achieve better purchase with screws if they do not protrude through the bottom course.

   Though plywood is very stable, I still leave 1/4" spacing at the edges, much like one dpoes for flooring.

   Other potential problems are your screw heads, make sure they are all flush with you ply. With 3/4" bottom and 1/2" top course, I can use 1" gold grabbers which suck up nicely without pre-drilling.

   have fun with it

   walk good

   david

1. 
   Ken_fisher | Dec 23, 2001 12:01am | #2

   *Greg:Personally, I've never been there with 3/8" material, rather 1/2" as David mentions. I've seen two layers of 3/8" glued and nailed over 1/4" cork, but that was for sound reduction in a highrise.Never used the Volara in this situation, but it sounds like an idea. If you're concerned with the squeeking you could always trowel on some Bostiks with a 1/8" notched trowel before screwing the sheets together.I have to wonder as you're a member of nwfa.org. What do they have to say about this? They have a members only forum which requires an ID# to get in. I'm kinda curious as to the subject material in this forum or is it more like posting questions in email and getting a reply?I've spoken to some members of the benefits or lack of in becoming a member at $450 per year. It appears to be a toss-up.

1. 
   Greg_Warren | Dec 23, 2001 02:51am | #3

   *David, I haven't seen a post from you in a long while. Thought you dropped off the site. Anyways, I now see that the spec in the NWFA Guidelines book calls out two 1/2" sheets of ply, glued, screwed or stapled. My client wants the floor to have a bounce, so the Volara foam has been added to the mix. I will probably install a layer of unmarked vinyl for a moisture barrier. I do have some 5/8" long 1/2" crown staples that could work for the 3/8 double sheet concept, but that would not meet the spec. Do you fully glue the first layer prior to the second sheet going down, and what size trowel do you spread it with? What size and length of screw do you use with the double 1/2" sheets?Ken, The NWFA membership is a good selling point with clients. One can quoate point and verse to sell your knowledge from the guidelines. GW

1. 
   david_thodal | Dec 23, 2001 08:07pm | #4

   *Greg, I lay the first course of sheets down dry, no adhesive. Then, I use the urethane foam, gun applied running a bead along the edge and criss-crossing the sheet I am laying down. With two 1/2" sheets of CDX, I would use 1" gold grabbers . Even with these you may have problems with flushing the screw ; that is why I like the 3/4"cdx for the first course. I have not found a good 3/4" self-grabber screw. I run screws about 8-12" on the edge and 16" in the field adding extra screws as the need may arise. I like the urethane glue over construction adhesive or mastic; easier application and flatter fit. Also I find the urethane holds extremely well.The vinyl sheet good as a moisture barrier is probably redundant as the double sheet of cdx is an excellent barrier. I have never had any problems with squeaks over concrete. I usually run rosin or felt paper on the concrete before the first course of cdx. The two sheets of cdx basically become one laminate. And your flooring application follows standard procedure: use a flooring paper and nailing pattern as you would on other floors. Always use power-cleats myself with an armstrong nailer, so have no experience with staples.I found myself very busy and not too interested in posting for awhile. Maybe the site has lost some of it's "charm". The last I heard you were thinking of relocating to Boise. You still in Cali? I liked you posting on the cherry medallion. Nice work.walk gooddavid

1. 
   Greg_Warren | Dec 23, 2001 08:53pm | #5

   *Staying in California. Idaho would have not been a good move in their economic condition. I have found that staples fasten plywood to plywood much better and one can apply them as fast as one can pull the trigger. But one must have your foot or knee weight close to the point of the staple being applied. I have staples as small as 5/8". What is the brand of the urethane foam caulking canister?

2. 
   Ken_fisher | Dec 23, 2001 11:51pm | #6

   *Urethane Foam?That's interesting. Always interested in different products. Greg, Bostiks makes a tough urethane caulk adhesive used in the application David speaks of, but darned if I recall the name. One project I worked on required the use of the stuff, while building up a subfloor area over ply and concrete so the hardwood would sit flush with the stone.The trim guys used the stuff extensively for attaching the final base to base "skirt boards"? This place(new construction) had no drywall so I'm kinda unfamiliar with the term, but did notice somebody placed the wrong height base in one area. The base was glued, screwed, plugged etc. It took two guys a full day to carefully remove some 40 lineal feet so as not to destroy the wood(1"X 10")skirt board...lotta wood chiseling going on. That's some tough adhesive!Yea, I kinda agree with the NWFA membership, and have some of their material and "bibles" which is foolish not to check from time to time. But, what about that members only forum?? I find it odd that you would be asking these questions here and not resorting to the organization?I suppose I need to know...hehe. I guess I'm looking for another forum to check out..LOL..but I'm not ready to shell out $450 yearly for a trademark logo on my business card, or stationary. Some of my apprehension comes from local members that don't deserve to be. Let 'em have at it, but it doesn't get them anywhere.Tell us about the members forum. Please;) Happy Holidays Guys.

3. 
   david_thodal | Dec 24, 2001 07:50am | #7

   *Greg and Ken, The product I use is manufactured by Flexible Products Company of Canada (flexibleproducts.com) under the name ENERBOND foam adhesive. I use a applicating gun, designed to be used with the standard style can screw fitting. I have had excellent results with it in a wide range of applications: subfloors, wood thresholds, drywall, exterior fascia an soffit. The gun allows good control on application and coverage is pretty reasonable. But it is not a trowel on mastic, nor is one required for cdx build-up.As far as using staples, I do like the way screwscan pull tight the two sheets of plywood. Sometimes that is an advantage. But no doubt staples will be many times quicker.walk gooddavid

4. 
   Greg_Warren | Dec 25, 2001 05:17am | #8

   *Ken, I could not find a members forum at the NWFA site. Where is it? I am aware of the Bostitck's caulk but it is not a foam that can squeeze together easily. I will be looking for that foam. David, I haven't decided whether to staple or screw the sheets together. I always choose the best method. One installer I know says he uses a standup screw gun. Have you used one of these type of fasteners, and will they install the 1" screw? The owner/builder didn't have an issue with switching from 3/8 to 1/2" plywood sheets. It is spec'd 1/2" in the NWFA Guidelines. I went to my new home under construction this late afternoon and saw a 5 gln bucket of water sitting on the upstairs subfloor. I figured that I should get rid of it before someone knocks it over. Only a floorman would consider this. I took it out to the exterior upstairs deck and threw the four gallons over the side. To my dismay, under about three inches of water was drywall mud. It slapped the top of the scaffolds(the house was just scratch coated a couple of days ago and is ready for the brown coat on Wednesday), and the drywall mud bounced off the scaffolds and on to the scratch coat. I ended up spending a half hour scrubbing the mud off with a hand broom and water. I didn't get it all off, just flattened it out. Then I scraped the scaffold planks clean. The learning curve to construction is painful. Tomorrow I am going back to rake the dry mud off the ground to finish the cleanup. Any flooring questions? GW

5. 
   Ted_Temple | Dec 25, 2001 09:40am | #9

   *Greg,We just did a large custom home with this application: 3/4" sturdifloor, 1 1/2" gypcrete with adequate drying time over radiant heating coils, floating double layer of 1/2" cdx with stagered joints each direction stitched with 7/8" crown staples (no adhesives), felt, and 3/4" Brazilan cherry. 8 months out and all seems well.

6. 
   Greg_Warren | Dec 25, 2001 06:43pm | #10

   *Ted, Thanks for the input. The 7/8 crown I'll look for. I will probably use the DT glue method though. I'm getting 5.00/ft to install a layer of sheet vinyl, the foam, two 1/2" sheets CDX, stapled. GW

7. 
   piffin_ | Dec 25, 2001 08:22pm | #11

   *The enerfoam was developed for application of sheetrock to walls and cielings. Is the enerbond you refer to the same product? I wonder if it is tested for flooring as well since the stesses would be more sever. The enerfoam is basicly the same kind of stuff you get in disposable cans for insulating around windows and penetrations but with less expansion chemical. You know if you've ever got that stuff on your pants or shoes that it doesn't come off easily. A twelve dollar can of Enerfoam goes farther than ten or twelve 10.5oz. tubes of glue for similar applications but you've got cleaning agent to buy and time cleaning the gun too.

8. 
   david_thodal | Dec 25, 2001 09:50pm | #12

   *piffin, Flexible products have two products that I am aware of; one is the ENERFOAM that you mention for drywall and accoustical tiles. The other is ENERBOND which is a stronger,more use rated product. I have been using it for several years on subfloors, wood floors and exterior trim details with excellent results. I know several other floor installers and carpenters around here that rate it quite highly as an adhesive.Though in general I do not have a high regard for adhesives in general, I find the ENERBOND an excellent product . I have even used it to glue concrete pieces that have blown out of slab edges with good results.A note on cleaning the gun. Of the several models of gun applicators I have used, I find minimal cleaning is better. I have been told that the cleaners actually decrease the lifetime of the gasket seals in the gun which allows the residual adhesive to set up. Make sure you keep the nozzel, shut tight at all times except when using the gun. Change cans quickly and always keep a can on the gun, even if empty. Otherwise you will be buying a replacement gun .walk gooddavid

9. 
   Greg_Warren | Dec 25, 2001 10:25pm | #13

   *I could not find the urethane glue you are discussing. The web site you notate is Dow Chemical with no reference to the product or Flex Products.

10. 
    Ken_fisher | Dec 25, 2001 10:48pm | #14

    *Greg:NWFA Networking You are able to access membership forums on line. Your member I.D. number will allow you to enter the General Forum to discuss industry issues and your unique business forum, i.e. dealer/contractor, to discuss issues specific to your business. It's electronic sharing of questions, answers and discussion with your peers!Enjoy the journey as you explore NWFA.org. Let us know how we can further enhance the site for greater benefit. We welcome your comments. This is mentioned at the bottom of the home page with a link. It's also accessable(members forum) on the left hand side of the home page. Good luck and let us know what it's all about:)http://nwfa.org/

11. 
    Greg_Warren | Dec 25, 2001 11:19pm | #15

    *Ken, There was only one post on the site w/no responses. Real floorman have no questions, only answers.

12. 
    Ken_fisher | Dec 25, 2001 11:32pm | #16

    *Greg:Hmmn, that's interesting. Only one? If I recall you can contact the gurus during regular business hours.US: 1-800-422-4556...8AM- 5PM CST?

2. 
   Greg_Warren | Dec 25, 2001 11:47pm | #17

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   This is an installation that I have not done yet. I have one comming up next month, approx. 4500 sf. I know the basic drill; 2-sheets of 3/8" plywood overlaped and screwed together over Volara foam and 6 mil plastic loose layed over the concrete. But what are the nuances?; Are there things to look out for, and what are the negetives; squeeking and popping noises? Fill me in. GW