Replies

1. 
   calvin | Mar 14, 2012 02:07pm | #1

   bski

   What does Duraceramic say? 

   ............besides, no luan.

2. 
   bski | Mar 15, 2012 08:16am | #2

   Yes, I saw this before I asked.  I guess the real question is what is the difference between underlayment grade and construction grade? I thought that you were always supposed to gap your plywood.  Congoleum says that any gap more than a 1/32 should be filled.  If you're filling the gaps, you might as well lay it tight.  Is the difference in underlayment the amount of plies it has?

1. 
   calvin | Mar 15, 2012 08:35pm | #3

   bski

   Ordinary sheeting will have a poor surface-some laminate overlays (that seemingly fell from somewhere b/4 it was pressed) and probably voids .

   Sanded BC ply will have one side gooder than the other, probably football patches but should be void "free".

   Multiply has more plys and no voids and a good surface ready for easily telegraphing through thin vinyl.

   The product your using is pretty thick, should bridge minor gaps but voids will be bad if you roll that reefer over it. 

   The reason for gapping is expansion, the reason for filling joints is telegraphing.   The gaps are so it doesn't buckle.  Never cram the sheets tight at the walls either.

   Clear as mud?

3. 
   GUNN308 | Mar 15, 2012 09:07pm | #4

   Why 1/2"? How thick is your

   Why 1/2"? How thick is your subfloor? 1/4" will do the job baltic birch is the best butt your seams and gap the perimeter. This is the technique I use and it has never failed me but I have only used Dura-ceramic in kitchens with an 1/8" space and then grout. I have never seen telegraphing of seams with this product. 

4. 
   bski | Mar 20, 2012 09:08am | #5

   Thanks for the answers. The reason I am going with half inch is because I want the transition to the other flooring to be close.  As far as gapping and filling, I do understand the purpose.  What I don't get is when you gap for expansion and the fill for telegraphing, haven't you just defeated the purpose of gapping? Are you saying that as long as you gap the outside perimeter like you do with hardwood that it won''t buckle at the seams?

1. 
   calvin | Mar 20, 2012 09:20am | #6

   Yes

   That's the idea.  Too much restricted pressure "might" buckle the flooring.

   Be especially wary of going over subfloor that's exposed to the moisture of a crawl below.  Definitely need to use a vapor barrier over exposed dirt or stone in the crawl to keep that moisture from migrating up to the bottom of the subfloor.

   In the olden days, it was not uncommon to see felt paper laid between the sub and underlayment.  Especially usefull when they used to use masonite as the surface under lino.  While it was smooth it also could blow up like a poisonous toad.