Hollow sound on newly installed SPC planks

Flooring Forum - DIY & Professional

Help Support Flooring Forum - DIY & Professional:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


New Member
Jul 18, 2021
Hello folks

I am new to flooring and TBH I don’t know what to really expect from LVP/SPC planks. So I am asking you who has more experience in this area. Maybe you have your opinion on my situation.

A couple of weeks ago I hired a contractor to install SPC planks to my house. I’ve decided to go with GAIA TERRA flooring brand that has a nice color and texture. Here is the product itself Terra - Products - GAIAFLOOR

I read about LVP/SPC and many guides say subfloor leveling is important. So before the project started I asked my contractor if he is going to do subfloor leveling. He said that he’ll take care of it.

My first floor had glued down floor (engineered hardwood if I am not mistaken) and the contractor said that removing it will take *a lot* of work. So to save their time they just install the floor on top of the existing one. The SPC floor was quickly installed. Though I have not seen that leveling has been performed over this subfloor.

I started using the new SPC floor and found that several places have hollow sounds when stepping on them. It quickly became annoying. I checked the new floor with a level and there are several noticeable bumps. You can see it here

Is it something to expect from an SPC floor or is it just a result of poor job and needs to be fixed? How to fix the issue? Is it something I can do myself or it has to be fixed by the contractor?

I am going to contact the contractor and ask him about it but I wonder what to expect in this situation?
Your contractor is what is professionally known as a hack.
There are so many things that are wrong about this that I don't know where to start.... basically you got hosed.
Those elevation changes are a nightmare with the floor you have and I am of the sound opinion that spc floors should not be installed over hardwood floors as well.
Contact them and explain these things and do not be happy about it.
Yep, what Mark said. Your specific floor calls for flatness of 1/8” within 6’. That would refer to a gradual dip or a gradual hump of 1/8” spread out over 6’. The way the level rocks says that your floor is not within flatness specs as per the manufacturers instructions. The real kicker here is that it specifically says in the instructions that wood floors glued to concrete must be removed. Concrete gives off residual moisture. Installing a floating floor on top of glued down hardwood floor will trap moisture between the concrete substrate and the floating floor there by causing the wood floor to expand and possibly buckle which would cause a situation exactly like you have now.
Much appreciate your answers folks.

This situation does not sound good. What would be the best way to fix it? Should the floor be disassembled and hardwood floor leveled? What are my other options?

Installing a floating floor on top of glued down hardwood floor will trap moisture between the concrete substrate and the floating floor there by causing the wood floor to expand and possibly buckle which would cause a situation exactly like you have now.

Huh. I really do not know why the contractor recommended installing over the existing floor then.

The way the level rocks says that your floor is not within flatness specs as per the manufacturers instructions.

Where I can find the manufacturer specification and installation instructions? Sorry if these are rookie questions. Now I feel that I should have read more about floors installation before hiring this installer so mistakes like this one could be avoided. What books/articles on this topic (general flooring/lvp installation/floor long term maintenance) would you recommend? I would like to learn more about it and be better prepared for my next project.
The link you provided for your specific product has the installation instructions within it. Your installer could have googled it, made a phone call or actually read the instructions. If for some reason the instructions were not provided with the product then options 1 and 2 would be the best bet.

We literally are the book :)
More helpfully, there are not a lot of general literature releases for the installation of floating floors. Manufacturers provide specific specifications and installation instructions and for the most part they are all the same.
The internet is a generous resource however there is as much good information as bad.... This forum, populated with seasoned professionals is the best place to find advice and solicited responses to any and all query

Your specific situation will require at the least the floor to be disassembled and flattened and then reinstalled. This should be accompanied with the removal of the hardwood floor as problematic as that may seem at this point.

Your vinyl floor has caused a situation that your hardwood floor cannot survive through and by its failing, so too will your spc/wpc floor due the conditions this creates.

None of this is what anyone wants to hear however, the truth is typically more useful than pleasantries and lies :)
Reading, and following, the instructions has become a thing of the past. The perception is that all floating floors are the same and if you’ve gotten away with something with one specific product that you can then get away with it with all products and usually in all situations.

I had a commercial job I did maybe 10 years ago where the GC saw me reading the instructions and asked me if I always read the instructions in a snarky kinda way. I replied ‘Yes I do. That way when something goes wrong I can say I told you so’. And I will!
I skipped the video, actually many other posts videos.

absolutely what Chris said, the hardwood will expand and go upward. Not sure how many times I’ve bid a demo job, they didn’t use my services and paid # # ? (How many times to do it right)
Sounds like another moron installed his brother in laws floor, he was shocked at how much money he saved his brother in law that he went into the flooring business.
In my area there are a dozen “phonies” on Craigslist and NONE of them instsll carpet because all they ever played with (notice I didn’t use the term “install” ) was click planks.
I even know a ceramic dude (not installer ) that won’t touch LVT “because his guys can’t get the floor that flat”

I’m sorry you got hosed but you got lied to about what is required to install your floor .

I have some really bad news for you. The guy that did this isn’t qualified to fix it.

More bad news , if you don’t use the right people to fix it you may end up literally losing the material that’s been installed and probably have . It doesn’t just come apart these joints aren’t designed to be taken apart over and over again

There is no good answer sorry

In comparison I charge 2 bucks a foot just to instsll planks of any design much more for wood. LEVELING , REMOVAL, FURNITURE is extra. Sometimes the removal and leveling is twice as much as install.

The craigslist installers “start at a dollar”
I wonder how many installers have an edger on the truck. OSB type floors I alway sand the joints as they expand with the glue they use on the floor joist. Lately been seeing 20 year old floors squeaking from the cheap construction glue they used.

Latest posts