Replies

1. 
   Dave_Ingle | Oct 13, 1999 05:38am | #2

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   Steve,
   Here's something to consider since you have used the OSB subflooring.......did it gey wet much and has it had time to dryout good? Once I put down 5/8 plywood underlayment with screws on top of what appeared to be dry OSB subfloor to matchup with hardwood( The house had been 'in the dry' for a couple of months I reckon at this stage).....anyway 6-9 months later 75% of the screw heads showed through the interflex vinyl I had installed. I had to replace the whole floor. It was weird, but all I could figure was that the OSB had swelled from moisture during framing(winter time),but eventually dried out.... I ALWAYS now install 1/4 laun with staples on 3-4" centers as the last layer before vinyl.

2. 
   Guest_ | Oct 13, 1999 06:23am | #3

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   Dave:

   You say "Interflex vinyl"... What is that?

   and

   I wonder why everyone uses 1/4" laun plywod???

3. 
   Mad_Dog | Oct 13, 1999 06:30am | #4

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   All I can say is forget the "self adhesive tiles". They are
   also "self unadhering tiles".

   M

4. 
   Guest_ | Oct 13, 1999 06:42am | #5

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   Really? Gosh, I wish ours were.

5. 
   Frank_LaPiana | Oct 13, 1999 10:53am | #6

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   (3) Poly behind the backerboard - if you're using a cement board, yes. The stuff isn't waterproof, it just isn't damaged by water.

   (4) I also had a problem with wonderboard "settling" - if you can, wait a few days after you screw it in, then go back and check the screws again before tiling.

   (4) Seams - thinset, fiberglass tape, a little more thinset.

6. 
   Guest_ | Oct 13, 1999 02:49pm | #7

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   I have used poly on the wallls but not on the floor. Doesnt this break the bond between the thinset and the backerboard.

   I used to use 1/4 luan under vinyl until l had some swell and telegraph through. Had to replace the floor. Vinyl manufacturer doesnt recomend plywood. There are several osb type products on the market. Check your manufacturers recomendation.

   Is BC a rated underlayment? If it is not you will void your warrenty. Try a 5/8 underlayment with vinyl on top it will work great with 3/4 floors.

   Rick Tuk

7. 
   david_ingle | Oct 13, 1999 04:18pm | #8

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   Matt,
   Interflex vinyl is the glue down around the edges type as opposed to the glue down all over type. At least that's what we call it around here.......at one point a couple of years ago,luan was the only underlayment some flooring companies around here would guarrantee there work over. I assume it was because of past experiences with the other underlayments available.

8. 
   Guest_ | Oct 16, 1999 08:47am | #9

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   1/4 luan plywood is not an approved substrate for any sheet vinyl. The reason everyone uses it is because it is cheap and widely available,(mostly from the Philipines).

1. 
   Guest_ | Oct 16, 1999 09:28am | #10

   *Reinhard:OK, so what is the approved substrait, who approves it, and why is 1/4" luan inferior?TIA

9. 
   Frank_LaPiana | Oct 16, 1999 10:22am | #11

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   Rick Tuk > I have used poly on the wallls but not on the floor. Doesnt this break the bond between the thinset and the backerboard.

   I was reading (I think it was at JLC) that the thinset doesn't do anything for adhesion, it's the nails or screws that hold the backerboard to the floor - so don't skip. The thinset is used to provide additional levelling.

   Anyway, I meant "use poly on the walls." But because of my kids, I did use poly on the floor as well, and made sure I screwed the wonderboard down tight. It seems quite stable over the past year or so, no problem with movement or cracking.

10. 
    Guest_ | Oct 16, 1999 10:27am | #12

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    Matt, I really don't know why it is not approved I'm sure it has something to do with money. I do know all the vinyl I have ever installed had disclaimers voiding the warranty if luan is used as the substrate. We always used 1/4 or 1/2 bc plywood.

1. 
   Guest_ | Oct 16, 1999 04:22pm | #13

   *Reinhard,You can get movement fron luan. Not much but it is enough to cause some joint fillers to crack and pop up.Form what I understand rated underlayment has all voids filled. BC plywood has the face filed and sanded, but may still have some voids on the inner layers.Rick Tuk

11. 
    Bill_Hobbs | Oct 18, 1999 06:28am | #14

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    I want to install vinyl flooring in a basement utility roon and recently added bathroom. I think an underlyament is necessary to ensure consistent flooring surface, but what is appropriate underlayment and what is the best way to fasten it?

12. 
    Guest_ | Oct 18, 1999 06:59am | #15

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    Point loads and High(spiked) Heels???

    Luann doesn't have the compressive strength?

13. 
    Dave_Ingle | Oct 18, 1999 07:30am | #16

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    Bill, is your basement floor concrete?......big difference as to response.

1. 
   Bill_Hobbs | Oct 22, 1999 03:55am | #17

   *Dave, our basement floor is concrete.

1. 
   Bruce_Binnig | Oct 27, 1999 04:14am | #18

   *I am having a house built using Durock behind ceramic tile in the bathrooms. The subs put the stuff up:1) without any vapor barrier over the wood studs behind2) using paper tape over the joints3) using drywall nailsThe Durock website says nothing about #1, but is explicit about #2 and #3. So, does one need a vapor barrier?Should I request Dens Shield?

14. 
    Guest_ | Oct 27, 1999 04:21am | #19

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    Uh, request/require a tearout and get a new sub is more like it.

15. 
    Guest_ | Oct 27, 1999 04:22am | #20

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    I have a couple Qs regarding underlayment for vinyl and ceramic. I have 3/4 tg OSB subfloor. Most of the house I plan on 3/4 hardwood flooring, but kithcen, mudroom and pantry will get vinyl.

    1) For the rooms which will get vinyl flooring, I have 1/2" sanded BC plywood for underlayment (to bring the level of the floor closer to the eventual hardwood finish level). What are some recommendations for fastening and for seam spacing/filling? Is priming the plywood necessary before laying the finish floor? All rooms but kitchen will be perimeter glued sheet flooring. I'm planning self adhesive vinyl tiles in kitchen for now, then upgrading later.

    2) For the master bath, ceramic tile will be used 4' up the wall, on the floor, and for the entire shower surround. I have 1/2" wonderboard. Some time back someone had recommended using a good subfloor adhesive with the fasteners to bond the backerboard to the subfloor. In a recent discussion, other folks recommended a full morter bed under the board. Anyone care to comment on the good or evil of using subfloor adhesive, which currently is my intended method.

    3) For the shower surround, should I install poly plastic on the studs before fastening the backer board? (note that I'm not intending a tiled pan)

    4) Any general tips for installing the backer board? (screw spacing, seam treatment, etc)

    Many thanks in advance. I'm in the home stretch now and can see the light.
    SWright

1. 
   Guest_ | Oct 13, 1999 04:34am | #1

   *A couple of quick comments re your numbered questions.1) Underlayment... one method is to use 1 3/8" narrow crown staples. Every 2" on the seams and every 3" in the field (center of plywood). Then use a quality leveling compound on seams and where ever needed.2) Backer board on floor - around here we set it on a layer of thinset - spread with a 1/4" notched trowel. Fasten the backer board down with roofing nails or backer board screws. I think that exposure 1 rated plywood is normally recommended for subfloor - not sure how this will effect things. Perhaps the subfloor adhesive would be better on the OSB the mastic is not cementous. Then we tape seams with a fiberglass mesh tape, more thinset then tile.