Replies

1. 
   Jeff_Clarke | Sep 17, 2009 03:25pm | #1

   Your first line of 'attack' should be fasteners, in which case adhesive (like PL400) is helpful, but not primary, and creep shouldn't be a factor at all.

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   Jeff

1. 
   IMERC | Sep 17, 2009 05:41pm | #3

   up grade to PL Premium...

   View Image 

   Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->

   WOW!!! What a Ride!

   Forget the primal scream, just ROAR!!!

    

   "Some days it's just not worth chewing through the restraints"

1. 
   hmj | Sep 17, 2009 06:54pm | #4

   That is what I generally use. Sure would be a hail of lot less messy than ssy rolling on TB3.

   What about poly subfloor foam

   http://building.dow.com/na/en/products/images/gspwallfloor.jpg

1. 
   IMERC | Sep 17, 2009 07:05pm | #5

   now that stuff can get out of control in a hurry... 

   Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->

   WOW!!! What a Ride!

   Forget the primal scream, just ROAR!!!

    

   "Some days it's just not worth chewing through the restraints"

1. 
   hmj | Sep 17, 2009 07:14pm | #6

   I've used it on walls and ceilings w/ no problem. (sometimes it falls off of the ceiling into your hair if it is real dusty)

2. 
   JTC1 | Sep 17, 2009 05:30pm | #2

   Did same for my own powder room some years ago.

   I sistered ripped 3/4" Sturd-i-Floor rated plywood to 2x8 joists, 11' span.

   The original floor had a significant amount of bounce before sistering and some delamination in the 1/2" plywood subfloor due to old leaks.  

   Removed old subfloor.

   Made a temporary header to span the room and jacked the joists up about 1/8" with screw post jacks set on the concrete basement floor.

   Applied TiteBond II glue with a 3" roller to the ply and joists.  Clamped ply to the joists with C clamps (messy - good thing I put down that poly!) and screwed the ply to the joists with 2" deck screws, 3" oc - a lot of screws - would be easier now with impact drivers. Removed C-clamps immediately after fastening as I needed them for the next joist.

   Left jacks in place for one week waiting for glue to cure.

   About day 4, I installed new 3/4" Sturd-i-Floor plywood subfloor with subfloor adhesive and #8, AR nails.

   Day 7, removed jacks and header with no creaks, snaps or pops heard.

   Installed 1/4" Hardibacker with screws and thinset to floor and tiled away.

   9 years later there are no cracked / loose tiles or grout. 6" square ceramic tile with 3/16" sanded grout. Powder room gets frequent use.

   So is it the screws or the glue doing the work? Don't know for sure, just know it is still working - tiles might start cracking tomorrow.

   Jim

   Never underestimate the value of a sharp pencil or good light.
1. 
   hmj | Sep 18, 2009 04:18am | #9

   I might use plywood instead of 2x8s. Some wires to deal with. 2x8 joists, 12 ft span. 3/4 plywood subfloor, with 1/2 plywood on top of that (at least on the part that is pulled up. I might have to take up the 1/2 plywood and put down 1/4, as I would really like an uncoupling membrane and floor height is an issue. Also plan on using metal strapping wrapped under each joist. Owner wishes for 2'x2' tiles.Today opened up a wall that they want gone and found 2 HVAC ducts that I somehow missed when looking in the basement. Fortunately, there is an old, unused Bvent from a long gone oil furnace, still in place so I can reroute the ducts through that space (minus the vent) and get to the second floor bedroom.

1. 
   JTC1 | Sep 18, 2009 04:34am | #10

   >> Owner wishes for 2'x2' tiles.<<

   That is a little touchier than my 6x6's.  But from the feel of my floor, they would be OK.

   Good luck!

   JimNever underestimate the value of a sharp pencil or good light.

2. 
   BillBrennen | Sep 18, 2009 10:17am | #11

   hmj,2x8 joists at 12' span will be too bouncy for 24" square tiles, in my opinion. Over at John Bridge's tile forum they have a bounce calculator to see if your floor will be good for tile. Check it out. Smaller tiles would be a lot safer, everything else being equal.

1. 
   hmj | Sep 18, 2009 02:56pm | #12

   Bill,I did make use of the deflectometer. have used it several times before. 2x8 at a 12 ft span has too much deflection for tile. However, sistering the joists to make a 4"x8" (NOMINAL) does pass muster. Agree that 2x2' tiles are big honking tiles but have seen them work on non slab floors before. Plan is to use metal strapping to add stiffness as well. Throw in some blocking if I am still not satisfied.I ddi try to talk em down in size, but some people get it in their heads....

1. 
   BillBrennen | Sep 18, 2009 05:48pm | #13

   hmj,I know what you mean about customers getting fixated on a concept. Ah well, so long as they pay you to do it correctly, then they can have their extra large floor tiles.One effect that I have noticed in tiling over wood-joisted floor decks is that the addition of tile reduces the perception of bounce significantly. My own dining room/kitchen/laundry room is tile over 1/4" Hardi over 1/2" ply over 3/4" diagonal boards over 2x6 joists @16" o.c. spanning up to 10 feet. The assembly seemed solid enough before the Hardi and tile went on, but I was amazed at how much more solid it became when the floor was complete. The tiles are alternating squares at 6" and 18". Even though the Hardi and tile are not considered structural, the high stiffness of the porcelain, coupled with the deadness of the Hardi, somehow act to stiffen and damp out vibration from the floor. After a decade it is still solid and quiet like a tomb, while the adjacent carpeted section over the same wood sandwich is squeaky and a little bouncy. This is my perception here, not any sort of measurement with instruments.

3. 
   Sbds | Sep 18, 2009 03:09am | #7

   When I sistered up my joists for my bathroom I used subfloor adhesive. I used a small sledge hammer and hit the bottom of the new joist in till it touched the bottom of the old joist at a 45 angle. Squeezed on the adhesive and used C clamps to pull them together. Then I used bolts every 10 inches and shot nails in between the bolts. Placed 3/4 inch subfloor and poured 1/2 of SLC over a heating mat and tiled. Have not had a squeak yet.

4. 
   Piffin | Sep 18, 2009 03:54am | #8

   I think of the glue for sisters as something to prevent squeak, more than as structural, so I don't consider creepiness.

   I use the PL Premium.

    

    

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5. 
   Hudson Valley Carpenter | Sep 18, 2009 06:27pm | #14

   Back in the time before manufactured floor systems, laminated beams, I-joists and etcetera we used to laminate our own sistered joists for long spans. 

   For one owner-designed house, I recall making up a number of 20' doubled 2X12's, with 3/4" plywood sandwiched in between, using the equivalent of Titebond applied with a paint roller.  Hand nailed with 16d commons. 

   That floor was/is very solid and quiet.  

   BTW: That glue is stronger than the fasteners, once it's bonded.  You could remove the fasteners and still have all the strength so don't get carried away with the fasteners. 

   
   

   
   

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   Edited 9/18/2009 11:43 am by Hudson Valley Carpenter