How important is it to follow the installation guidelines to the T to make sure you're still covered under the warranty? It sounded like the surface prep and installation process and material used could determine the outcome of the claim if it happens.

Has anybody gone through the process of claiming and if so, what has been the experience?

Inspectors activly look for resons to deny the claim, if you dont follow the guidlines your warranty work will be denied without question even if it doesnt pertain to the problem at hand.

It's very important. In fact many seasoned installers get tagged for not following guidelines. All I gotta say is do it right and document it. Especially when it comes to moisture testing and substrate flatness.

We will be installing Mannington engineered hardwood. I've checked their website for warranty info and installation instructions/handbook. They suggested using their UltraSpread Mastic and MVP 2023 patching compound. While they list their own products, I wonder if using comparable polyurethane adhesive and quality leveling compound will void the warranty.

They also mentioned that concrete subfloor must be visibly dry with no history or evidence of excessive moisture vapor transmission. Does it mean we can get signed statement with backup pictures from the installer or do we actually need to perform Calcium Chloride test to prove that it is < 5 lbs moisture vapor transmission (as mentioned in the instruction as frame of reference)? It almost sounded like you are require to do visual inspection AND moisture test. The other portion of the house already has wood floor installed when the house was originally built 6 years ago and is performing well with no signs of moisture issues.

Any other specific issues that you can see that the seasoned installer may have been 'tagged' by the warranty inspectors?

It's always good to use a manufacturers products to avoid the blame game if you can. But yes, should not be a problem.

Mannington said that about "visibly dry" ? LOL Thats just dumb. However is there system (adhesive and patching compound) also a combo vapor retarder? If so use it.

Mannington is very strict about honoring waranty issues, ( I was a "Mannington Certified Claims Adjuster"). You must always use their specified products, or forget warranties.
Example: An adhesive manufacturer will change the color of an adhesive exclusively for Mannington. This exact same adhesive will be available by the manufacturer under their own label, but not the same color, (at usually less cost). Using the manuf. labeled adhesive will void Mannington's warranty.

Well theres an authoritative answer.

Hey Howard, aren't they the ones who did the "strike a match on the concrete" for mositure testing?

Can you explain that one?