[michaelcpaul]

Hi, looking for some advice regarding a snag I'm running into replacing particle board in a kitchen to prepare for tile. The existing floor is (bottom to top) 1/2 osb, roofing felt, 5/8 particle board. The problem I have is there isn't any 5/8 plywood available so I need to go with 23/32. This results in an extra 3/32 of height above the floor in the rest of the house. This wouldn't be an issue except for the fact that I need to maintain about of foot of particle board in the kitchen along a wall in order to terminate the replacement plywood on a joist. So here the hardibacker will span the plywood and a strip of particle board (see the picture using view album on left). I'm going to use waterproof glue to 'paint' this strip of particle board to mitigate the issue with wet mortar and particle board. Not ideal, I know, but let's not get hung up on this

I'm looking for some ideas on how to handle the 3/16 gap between the hardibacker and the particle board along this strip. Any ideas?

 

[taylorfain2009]

Re: Replacing particle boar in preparation for tile

Picture won’t load for me


The more beer I drink the straighter my cuts become

 

[michaelcpaul]

Yeah, not sure why it doesn't show up. Are you able to see it under view album on the left?

 

[taylorfain2009]

Yeah, not sure why it doesn't show up. Are you able to see it under view album on the left?

No sir. Maybe it’s my error... I’m not sure


The more beer I drink the straighter my cuts become

 

[michaelcpaul]

 

[P C D]

5/8" plywood is a standard size; if your local lumber yard does not stock it, you can special-order it. You can also use 1/2" plywood over 1/8" hardboard, or 3/8" plywood under 1/4" cement tile backer.
Are you sure that your structural deck is only a 1/2" OSB? That sounds too small for typical 16" o.c. floor joists.

 

[michaelcpaul]

https://www.diychatroom.com/members/michaelcpaul-570591/albums/subfloor/39527-subfloor.png

this is the correct picture:

 

[michaelcpaul]

5/8" plywood is a standard size; if your local lumber yard does not stock it, you can special-order it. You can also use 1/2" plywood over 1/8" hardboard, or 3/8" plywood under 1/4" cement tile backer.
Are you sure that your structural deck is only a 1/2" OSB? That sounds too small for typical 16" o.c. floor joists.

Yes, it's 1/2". From what I've read in other posts it seems that sort of backwards, in that the thicker layer is usually the bottom layer?

 

[chandler48]

or 3/8" plywood under 1/4" cement tile backer.

cbu offers nothing structural, so it can't be used as such.

Consider using a kick saw and cutting the 5/8 particle board flush with the wall, then install 23/32 plywood or Advantech in the strip.

 

[P C D]

Yes, it's 1/2". From what I've read in other posts it seems that sort of backwards, in that the thicker layer is usually the bottom layer?

The 5/8" particle board in the rest of the house is not structural, so all you have to support the floor between the joists is that 1/2" OSB. If you get 5/8" OSB or plywood to replace the 5/8" particle board, it will help with the added load from the cement boards and tiles.

It sounds strange to me that you cannot find 5/8" ply or OSB in your area, that being a very standard size. If you use 3/4" ply instead, you should be able to make up the gap with strips of 3/32" material.

 

[michaelcpaul]

cbu offers nothing structural, so it can't be used as such.

Consider using a kick saw and cutting the 5/8 particle board flush with the wall, then install 23/32 plywood or Advantech in the strip.

This would be my preference, but my concern with cutting flush to the wall is that the new plywood would fall between joists there and would only be supported by the 1/2" osb.

 

[michaelcpaul]

The 5/8" particle board in the rest of the house is not structural, so all you have to support the floor between the joists is that 1/2" OSB. If you get 5/8" OSB or plywood to replace the 5/8" particle board, it will help with the added load from the cement boards and tiles.

It sounds strange to me that you cannot find 5/8" ply or OSB in your area, that being a very standard size. If you use 3/4" ply instead, you should be able to make up the gap with strips of 3/32" material.

Well, as it turns out both Home Depot and Lowes do carry 19/32 plywood which seems to be what serves as 5/8 now days. I wasn't looking specifically for 19/32 and I was seeing a jump from 15/32 to 23/32 and just missed it. Even if there is really a 1/32" difference, I can more easily work with building up the 19/32 than dealing with the extra height with the 23/32. Thanks for the reply.

 

[michaelcpaul]

Thanks for all of the responses! I have a path forward and I think we can close this out.

 

[P C D]

Well, as it turns out both Home Depot and Lowes do carry 19/32 plywood which seems to be what serves as 5/8 now days. I wasn't looking specifically for 19/32 and I was seeing a jump from 15/32 to 23/32 and just missed it. Even if there is really a 1/32" difference, I can more easily work with building up the 19/32 than dealing with the extra height with the 23/32. Thanks for the reply.

In the real world, your -1/32" will become +/-1/16" if you are lucky, which should not bother you.