# Increase height of subflooring



## HarryJ (Jun 10, 2011)

3/8" ply is a good idea

-Glue and Screw? i prefer to staple anything less than 1/2"
-Run parallel or perpendicular to existing subfloor? it doesn't matter as long as you overlap joints at least 6"
-Butt snug or leave gaps on joints? butt is fine
-Screw Length? did i mention staples? 1-1/8" with 1/4" crown
-Should I be trying to hit the floor joists (I already screwed down the OSB with 2" subflooring screws)? not necessary


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## joecaption (Nov 30, 2011)

Underlamnet is never glued to the subflooring.
Do not fasten the underlament to the floor joist. Your trying to pull the to together so there's no gap between the floor joist.


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## oh'mike (Sep 18, 2009)

Harry and Joe have given you good advice---avoid hitting the floor joists--do not use glue---3/8 inch minimum thickness----screws are fine but slow and expensive---small crown staples (lots of them) are fast--easy and effective---


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## oh'mike (Sep 18, 2009)

DO NOT GLUE---follow directions given by the pros--

This is an open public forum and not all advice is sound and backed by proper education and years of experience---


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## framer52 (Jul 17, 2009)

Personally I would not worry about the 1/4" difference in height between the two floors. You will need a transition piece anyway as the two should have 1/2" between the surfaces.


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## creeper (Mar 11, 2011)

jasin said:


> "Glue it & screw it" (Mike Holmes)


Where's Bud?


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## thiggins18 (Feb 3, 2012)

joecaption said:


> Underlamnet is never glued to the subflooring.
> Do not fasten the underlament to the floor joist. Your trying to pull the to together so there's no gap between the floor joist.


Ok thanks. Just picked up the stuff to do it right now, 15/32 in. x 4 ft. x 8 ft. 3-Ply Rtd Sheathing is what I'm using... Thats ok right ?














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## joecaption (Nov 30, 2011)

Nope, should have been underlament rated.
Sheathing will have unfilled knot holes in the plys, and not enough plys.
I also use a narrow 1-1/2 crown staple when attaching thinner plys. I can set it in automatic and nail a whole sheet in 1 min. and it leaves no dumples or big holes that would need filling it you were laying sheet goods.


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## thiggins18 (Feb 3, 2012)

joecaption said:


> Nope, should have been underlament rated.
> Sheathing will have unfilled knot holes in the plys, and not enough plys.
> I also use a narrow 1-1/2 crown staple when attaching thinner plys. I can set it in automatic and nail a whole sheet in 1 min. and it leaves no dumples or big holes that would need filling it you were laying sheet goods.


So I need the 15/32 In. x 4 Ft. x 8 Ft. BC Sanded Pine Plywood ? When I looked at it it looked like the only diffrence is the sanded pine vs the sheating was the sheeting was sanded... so what your saying is its sanded and filled?


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## JazMan (Feb 17, 2007)

Sheathing is not for floors, as Joe said. it might be good enough since you're covering with wood, but............ The willingness to spend less can be costly in the end.



> -Run parallel or perpendicular to existing subfloor? it doesn't matter as long as you overlap joints at least 6"


Absolutely wrong answer. The new underlayment must run parallel, but offset to the subfloor. In other words, all subfloor & underlayments should run perpendicular to the joists....always. 

And of course no gluing to the subfloor and do not try to "hit" the joists. Of course if you use the right fasteners they will not be long enough to hit the joists. It's usually a good idea to leave an 1/8" gap between sheets and at least 1/4" at perimeter.

Jaz


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## thiggins18 (Feb 3, 2012)

Is the difference between the sanded ply and the sheeting ply the sanded is free of voids (and obviously sanded)?


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## HarryJ (Jun 10, 2011)

sanded only guaratees free of voids on the surface.

For your specific needs a cheaper standard ply will be great.
The extra benefits from a sanded product is just money flushed down the toilet.


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## thiggins18 (Feb 3, 2012)

Arggggg Do I have to go to somewhere other than HD or Lowes? The only stuff they have around a 1/2 inch is 15/32 sheathing, 15/32 rated sheathing, and the sanded.


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## thiggins18 (Feb 3, 2012)

HarryJ said:


> For your specific needs a cheaper standard ply will be great.


What do you mean by standard plywood?

I've called around to building suppliers and my options are.

CDX yellow pine (sheathing), BCX plywood, ACX plywood, CDX Fire retardent, baltic birch (expensive), and sandply (also expensive).

I guess BCX is certified for use as underlayment.


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## HarryJ (Jun 10, 2011)

the sheathing is fine. it sounds like your just needing the height, as long as you stick to plywood (not any kind of particle board) you can use anything thats available. Your scenario really calls for the cheapest thing you can buy.... AS LONG AS ITS PLYWOOD (that was my outside voice  the need for sanded or guaranteed filled knots doesn't matter for your application.


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## JazMan (Feb 17, 2007)

> Do I have to go to somewhere other than HD or Lowes?


Not at all, HD should have at least one choice and Lowes has at least two. You can also shop at a real lumber yard where you'll have a better chance of speaking with someone who knows lumber. 

You need underlayment grade, with exterior glued plies. The easiest to find is B/C grade. So, BCX & ACX should be the right ones rated for underlayment. Birch underlayment would be very good, but unnecessary in your case. 

Lowes shows;http://www.lowes.com/pd_12227-99899...d_nbr|0||p_product_quantity_sold|1&facetInfo=
*AND http://www.lowes.com/pd_7707-99899-...d_nbr|0||p_product_quantity_sold|1&facetInfo=

It would also be helpful if people would show their location for more accurate answers concerning products and also methods. We promise not to show up at your door. 

Jaz


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## HarryJ (Jun 10, 2011)

if i was doing it i would use the 3-ply sheathing you already picked up


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## JazMan (Feb 17, 2007)

> if i was doing it i would use the 3-ply sheathing you already picked up


Harry, maybe you're not getting the idea of these forums or why manufacturers and associations have specifications regarding proper products and methods. Sheathing for underlayments is not the correct product to use. Can it work though? Yes it will most of the time especially if installing nail-down hardwood. But it is still a poor grade for the job. We are here to give "correct" advice, not just answer with what has worked for us on several occasions, or even many times. 

Products and methods have been tested and that is why we have specifications. There are enough things that could go wrong even when all specs are followed, we as "pros" should not encourage people to cut more corners to save $50. In the end some people cut corners anyway, sometimes not even realizing it. As professionals we should not promote "hack" work. 

Jaz


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## jasin (Jan 22, 2012)

thiggins18 said:


> What do you mean by standard plywood?
> 
> I've called around to building suppliers and my options are.
> 
> ...


CDX is inexpensive because its a lower grade. Any plywood starting with a C will be lower quality. Meaning, It has a lot more voids, knots, etc. I personally would never use lower grade for sub-flooring.


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## jasin (Jan 22, 2012)

JazMan said:


> Harry, maybe you're not getting the idea of these forums or why manufacturers and associations have specifications regarding proper products and methods. Sheathing for underlayments is not the correct product to use. Can it work though? Yes it will most of the time especially if installing nail-down hardwood. But it is still a poor grade for the job. We are here to give "correct" advice, not just answer with what has worked for us on several occasions, or even many times.
> 
> Products and methods have been tested and that is why we have specifications. There are enough things that could go wrong even when all specs are followed, we as "pros" should not encourage people to cut more corners to save $50. In the end some people cut corners anyway, sometimes not even realizing it. As professionals we should not promote "hack" work.
> 
> Jaz


This is very good advice! :thumbsup:


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## thiggins18 (Feb 3, 2012)

JazMan said:


> It would also be helpful if people would show their location for more accurate answers concerning products and also methods. We promise not to show up at your door.


Haha considering I pratically I live right next to you (Orchard Lake). I wanted to keep my address secret :wink:

Thanks for your help I'll go pick up some BCX on my way home. So I can get this thing underway!


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## JazMan (Feb 17, 2007)

Higgins,

I'm not picking on you or anyone else who posts here. It's a fact that most people wouldn't think to mention (location) when asking their questions. But it really matters if you're located in northern Canada or Houston even for interior projects. This site should make the point of suggesting you enter your location when you sign up. 

Aha, Orchard Lake, a very nice place to live. Good luck with the project. 

BTW, that marble on the bath floor.....is that over a "mud" base or double ply with a concrete board? How long have you been walking on it. Has it worked out well? 

Jaz


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## framer52 (Jul 17, 2009)

I have a feeling neither jazman.


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## thiggins18 (Feb 3, 2012)

JazMan said:


> Higgins,





JazMan said:


> I'm not picking on you or anyone else who posts here. It's a fact that most people wouldn't think to mention (location) when asking their questions. But it really matters if you're located in northern Canada or Houston even for interior projects. This site should make the point of suggesting you enter your location when you sign up.
> 
> Aha, Orchard Lake, a very nice place to live. Good luck with the project.
> 
> ...




Jaz I didn't think you were picking on me or anything, I just wanted to do the job right. I appreciate your helpful insight. The flooring I'm installing will also have an inlayed border so I want to make sure everything is perfect so the final product turns out well. 

It’s hard to see the underlayment of the tile flooring because of the metal band (hallyway) and the cap (bathroom). There is a base of mud that’s pretty thick I’m guessing 5/8"+ I don't think they can lay mud that thick so I would assume there is hardibacker. From what I can see under the tile is goes like this...

3/4" OSB
Felt Paper
Hardibacker ?
Mesh
Tile (3/4")


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## jasin (Jan 22, 2012)

The National Tile Contractors Association recommends that OSB NOT be used as subfloor.


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## oh'mike (Sep 18, 2009)

thiggins18 said:


> Jaz I didn't think you were picking on me or anything, I just wanted to do the job right. I appreciate your helpful insight. The flooring I'm installing will also have an inlayed border so I want to make sure everything is perfect so the final product turns out well.
> 
> It’s hard to see the underlayment of the tile flooring because of the metal band (hallyway) and the cap (bathroom). There is a base of mud that’s pretty thick I’m guessing 5/8"+ I don't think they can lay mud that thick so I would assume there is hardibacker. From what I can see under the tile is goes like this...
> 
> ...


Sounds like a Jersey Mud set---not good---


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## JetSwet (Jan 21, 2012)

@ Thinggins18, can you upload a photo of what you are seeing? That might help us better.
Thanks

Sent from my iPhone 4 ios5


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## thiggins18 (Feb 3, 2012)

oh'mike said:


> Sounds like a Jersey Mud set---not good---


After the bedroom and the hallway is done I will be putting some woodfloor in a halfbath off the great room. For some reason the marble wasn't laid in the bathroom and its 12x12 builder grade tile. I should be able to figure out whats under the tile then... The marble has been installed for 7 years now. It still looks very good...

Actually one more question while I have the ear of the professionals. Is there anyway to polish onyx tiles? We have them in another room and they look somewhat hazy.


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## thiggins18 (Feb 3, 2012)

JetSwet said:


> @ Thinggins18, can you upload a photo of what you are seeing? That might help us better.
> Thanks
> 
> Sent from my iPhone 4 ios5


Yeah Ill snap a pic when I get back home.


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## framer52 (Jul 17, 2009)

oh'mike said:


> Sounds like a Jersey Mud set---not good---



Could you explain this term.

If it is 1 1/2 inches of mud on the floor, that is the way all tile used to be set......


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## JetSwet (Jan 21, 2012)

framer52 said:


> Could you explain this term.
> 
> If it is 1 1/2 inches of mud on the floor, that is the way all tile used to be set......


Jersey mud jobs are used quiet often on this forum that I have seen so far I don't know if it's the jersey shore tv show or there driving lol but I never seen there tile work so could it be any better then those two things? Lol

Sent from my iPhone 4 ios5


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## JazMan (Feb 17, 2007)

Higgins,

What you described a few posts ago does not sound correct. I don't think you've got what you think under the tiles. 



> 3/4" OSB
> Felt Paper
> Hardibacker ?
> Mesh
> Tile (3/4")


There is no felt or mesh (lath) when any concrete backer is used. Plus your tiles are not 3/4". Let us know.

Jaz


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## JetSwet (Jan 21, 2012)

JazMan said:


> Higgins,
> 
> What you described a few posts ago does not sound correct. I don't think you've got what you think under the tiles.
> 
> ...


It could be possible that he has mesh for a filler well just have to wait for the photo.
Or he could be seeing durock instead of backer board hence the mesh looking idea.

Sent from my iPhone 4 ios5


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## thiggins18 (Feb 3, 2012)

thiggins18 said:


> 3/4" OSB
> Felt Paper
> Hardibacker ?
> Mesh
> Tile (3/4")


 
Ok my bad. Looks like:
3/4 OSB
Felt Paper
Mesh
Grout
3/8" tile maybe 1/2" not sure

Started putting down the sub flooring and the scews I am using (Gold 1.25" Grip Rights), some of them spin out and will not drive deep enough to counter sink. I think I might go the stapler route. :furious:


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## JetSwet (Jan 21, 2012)

That looks like just a big bag of nonsense there....
Ply
Durock that's in bad shape, 
maybe backerboard?.. defiantly more cement filler of some sort 
And some thick tile

Sent from my iPhone 4 ios5


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## jasin (Jan 22, 2012)

Op could use an underlayment like Schluter-DITRA. That is an option too. You can mud directly on top of that and then lay the tiles. I believe he can still use the hardi board too if he needs.


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## jasin (Jan 22, 2012)

JetSwet said:


> That looks like just a big bag of nonsense there....


I was thinking the same :laughing:


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## oh'mike (Sep 18, 2009)

Jersey mud set---not an accepted tile installation method----expanded mesh stapled to the subfloor--some times with a tar paper underliner---then thinset troweled into the mesh--then the tile


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## thiggins18 (Feb 3, 2012)

joecaption said:


> Nope, should have been underlament rated.
> Sheathing will have unfilled knot holes in the plys, and not enough plys.
> I also use a narrow 1-1/2 crown staple when attaching thinner plys. I can set it in automatic and nail a whole sheet in 1 min. and it leaves no dumples or big holes that would need filling it you were laying sheet goods.


Who would have thought laying an aditional 1/2" would be so hard... My newst problem is I have two staple guns a Porter Cable that can shoot a maxiumum of 18g 1" staples or a Dewalt that shoots 16g 1-2". The only problem is nobody carries 16g 1.25" in a box thats smaller than 10k

Would using a 18g 1" be a bad thing?


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## oh'mike (Sep 18, 2009)

To short---That's a problem for you guys that don't do this kind of work all the time---

Man do you get whacked buying the little packages of fasteners--


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## JazMan (Feb 17, 2007)

Higgins,

We may be wasting time talking about the part that is already done and you claim is in good shape, but....... 

I'm not sure what I'm looking at the that pic. What is that material over the OSB? The concrete over that looks like too thin mud, but not sure. It could be 1/2" Durock or Wonderboard. 

I do not see a Jersey Mud job though. We don't do that much around here.

Jaz


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## thiggins18 (Feb 3, 2012)

oh'mike said:


> To short---That's a problem for you guys that don't do this kind of work all the time---
> 
> Man do you get whacked buying the little packages of fasteners--


I ended up going to a place that specializes in fastners. Fasteners Inc (Livonia). I eneded up buying some Paslode 1/2" crown 1 1/2" Legnth 16 guage staples for my medium stapler. The guy that worked there was very knowledgable and said Paslode recommends 1" peneration threw the material your attaching (in my case 1/2" ply).

I gotta plug this place because there are the cheapest I could find these staples... and they beat the lowest price I could find on the internet and around town by $20.00+, I think they beat Lowes and HD by $60.00+


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## thiggins18 (Feb 3, 2012)

JazMan said:


> What is that material over the OSB?


It feels like felt paper.


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## JazMan (Feb 17, 2007)

OK it's paper, just didn't look like it. So, it's a poorly done mud job. I say that cuz a proper mud should be at least 3/4" thick, and that looks barely 1/2". I might be wrong on the thickness though. However it's done and holding up fine.

I agree about Fasteners Inc. It's their specialty.

OK, back to this project. 

Jaz


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