Fiberock underlayment on slab making popping sound

Based on the installation instructions (attached) and your comment above I'd say they didn't follow the installation instructions if they used spacers in between the boards.

Per the installation instructions:

"...Butt panel edges and ends lightly together. =A maximum 1/32" gap is allowed."​

I've never seen any type of wedge spacer system that is 1/32" or smaller so they've allowed too much gap between the panels. It's very likely that what you've stated in your post is what is occurring regarding the remaining portion of the spacers but based upon what the panel manufacturer is saying in their installation instructions, they should have never used a spacer to begin with.

Sounds like somebody has got a lot of demo work ahead of them.

 

Thanks for catching that Jim. I missed that little blurb as I was reading the panel installation section.

What Jim's said is obviously the much bigger issue vs. what I posted.

 

Once the current situation you have is removed back down to the slab, the simplest thing to do is use a self-leveling cementitious underlayment to bring the floor up. There are several manufacturers that have products designed for this type of application. Uzin, Mapei, and Ardex are some of the most popular manufacturers of these types of products. Each of these companies have multiple products at multiple price points with slightly different characteristics.

Some products work quickly (16 hours minimum cure time for something like this is considered quick) but the speed comes with a higher price tag generally. Other products require a bit longer curing time (2-3 days vs. 16 hours) but these are generally less expensive. Within each one of these characteristics each manufacturer will also have products that can only be poured up to say 1" thick per pour while other products will be able to do the hole thickness in 1 shot.

Based on your original message it sounds like you've got a 1/2" thick engineered wood product so to get to level with the marble floor you would need to level 1 1/2" if I'm understanding correctly. To do a rough calculation on about how much self-leveler you will need you can calculate about 1 lb. of leveler per square foot at 1/8" thickness. That being said you're roughly talking about 12 lbs. of self-leveler per sq foot of area at 1 1/2" thickness.

Depending on the manufacturer and the product selected you may have the option to utilize clean pea gravel mixed into the product to prevent having to purchase so much leveler and save costs. The manufacturers will each have specific recommendations on how much (what ratio) this can be added if it's acceptable for the product that is selected.

Each manufacturer will also have recommendations as to whether or not a primer is needed prior to the self-leveler being poured. Coverages and specific installation instructions will vary across products.

A decent self-leveler from a supplier will range from about $20.00 per bag (generally 50# bags) to about $55.00 per bag for the faster products with more "bells and whistles".

Labor will depend upon your local market and can vary drastically based upon the skill level of the installer and their comfort level with self-leveling.

Hope that at least helps with a possible solution for your situation.

 

I hear guys say they've been doing this or that for years, blah, blah, blah. They have just been doing it wrong for years.

 

Moisture from thinset then hardwood on top. There was all sorts of discussion on how to save money, I get it.

Fiberrock I’ll have to look up. So he used medium bed mortar maybe Mapei Lowe’s or custom Home Depot. Possibly Ardex. There’s just so many things that can go wrong that’s why it’s not recommended. Even leveler is tricky if not followed by more than experienced but trained personnel.

Some would’ve put a sleeper system down and used naildown hardwood. If it were a good hardwood installer.

I assume fiberock is like Hardiboard which gets fastened to wood subfloor by screws/galv nails. So not exactly how much wood content is in those products probably why not for slab cause it’ll expand from moisture. The thinset under it is just to fill voids after fastening.

Fiberrock, Gypsum based cellulose product, of course, it’s in their name. In this case it’s used as “filler” material.

This weeks Bill is around 9k$ for two jobs(Failed) that never were approved by the TCNA, sheet vinyl paper backing glued down, then thinset and tile. But I’m not complaining.