Easy to be confused by flooring options. In the vinyl category you have the sheet format and tile and plank formats. Some in each category are installed with adhesive and some are not. Perhaps the sheet you chose can only be installed using adhesive...in that case the estimator would be correct in stating that it cannot be installed over particle board. You have to check to see which can be installed directly over particle board. Information from manufacturers, either on the packaging or in technical specifications on their websites, can tell you what is an acceptable substrate for each product and how the substrates must be prepared.

Even if you decide to glue down the vinyl plank over the particle board (which isn't ever really recommended) you wont get your desired outcome. Particle board isn't a smooth and flat surface and vinyl has extremely little forgiveness for subfloor discrepancies. Either pull the particle board out and install a new 1/4" plywood for your subfloor, or for the smoothest and flattest installation, remove the particle board, install wire mesh and pour self leveling mix and allow to cure before installing the vinyl. Granted, that added prep will cost more, but depending on how long you would like your vinyl flooring to last, it is the best option for long term. And it gives you a truly flat subfloor for your vinyl. How to achieve a truly flat subfloor The Importance of a solid subfloor The Couture Floor Company

I have found 23/32 Advantech flooring panels at Lowes with list that the actual dimension is 0.688". The don't carry 5/8". The OSB and Ply they carry is 19/32", with actual measure dimension at 0.563". My old chip board is dead on at 5/8" when I measure which is 20/32" and translates to 0.625". With these figures, I was going to go with the 23/32 because it is actually only 1/16" thicker than my existing chip board at 0.624". If I go with a ply or OSB in 19/32" I'm really getting 0.563" which is 1/16" thinner than my existing chip board. I figure either way, the change is 1/16" between underlayment and I might as well go a bit thicker with the Advantech. Also Advantech advertises that they don't gas off formaldehyde because of the type of formaldehyde used, and the encapsulating resins used to make the product. I did get all the particle board up and installed decking screws to reenforce a few joist to the existing plywood subfloor where there was a squeak. Worked good. Any thoughts on my plan to get the 23/32" Advantech would be welcomed. I will be getting 6 sheets to cover 168sf. Also, my understanding of applying this Advantech underlayment, is that I only screw into the ply subfloor and not the joists. But the above comment by G&S floor Service on Sunday, is unclear to me. It sounds like G&S is saying to add screws to both the joists and the overall field of the underlayment (new install of Advantech over 1/2 ply). I would like clarification on this point. Thanks.

You have lots to get lined up before you get to install your bamboo. The subfloor moisture rating MUST be taken once it has been installed. The moisture rating for the wooden subfloor (the new layer) must be LESS than 12%. But more importantly it must be within 3% of the bamboo. That sounds logical until you realize that wood moisture meters have a hard time dealing with strand bamboo. They must have a special setting. Please make sure your install has access to this type of meter....or you could be voiding your CaliBamboo warranty before you have laid a single plank. The other thing CaliBamboo is SUPER SERIOUS with: Vapour Retardant over wooden substrates. Here's what the installation instructions say about that: https://www.calibamboo.com/content/installation/instructions/cali_bamboo_flooring_installation_guide.pdf "Wood Subfloors: For best results, use a vapor retarder with a perm rating between 0.7 and 50 when tested in accordance with ASTM E-96 Method A. Install as recommended by the manufacturer. Examples of acceptable vapor retarders for wood subfloors include: Asphalt laminated paper (UU-B-790a, Grade B, Type I, Style 1a.), Asphalt-saturated kraft paper, and Silicon Vapor Shield." This requirement is very different from many other floating flooring projects. Most floating floors just need to click the product together and move on. CaliBamboo (click together bamboo is a WHOLE DIFFERENT UNIVERSE) is not the same as installing laminate or vinyl. Remember: Bamboo can be as much as 30% ADHESIVE BINDER. The binders react to moisture DIFFERENTLY then the bamboo strands themselves. That's why you must have TIGHT humidity control. I know CaliBamboo says 30% - 60% RH to be the living condition requirements BUT (and this is a B I G BUT) your day-to-day conditions MUST NOT swing more than +/- 5% in either direction. A +/- 15% swing (as shown above) is FAR TOO MUCH. You cannot have 45% one day, then 60% the next (+15%) and then 30% the next (-15%). You will have massive problems inside of a year. In other words, if your floors were installed/acclimated to 35% humidity (which is low for bamboo) the swing cannot be more than 30% - 40% RH (relative humidity). Please ensure your new HVAC has the ability to add AND subtract humidity at the touch of a button. Whew! Bamboo is tricky!