Im looking to buy some lvp (actually spc) from lumber liquidators. The product will be 7 to 8 mm.

They are telling me that even if the lvp has a backing attached, I must still put down an underlayment or they will not warranty the flooring. They say homedepot and lowes have the same requirement.

is this right?

I thought 2 underlayments would allow excessive movement along the joints and increase the chances of the planks disconnecting??

 

Nope. 1/4" underlayment is pretty standard with vinyl.

 

My fault, I meant underpad.

Should I use underpad if underpad is already installed on the bottom of the vinyl plank?

 

So if manufacturer indicates it's needed to keep warranty, why are you asking for advice to eliminate?

 

Because:

firstly the manufacturer did not tell me to use additional padding, the person selling the flooring did. I dont think the warranty is worth anything.........look at the hundreds if not thousands of reviews on the internet of people saying the manufacturer wont stand behind even obvious manufacturing issues

secondly its to lumber liquidators benefit to sell me additional underpadding.....not mine.

thirdly as a person of mechanical back ground with alot of experience in home repair and floor installation it seems to me that too much padding under a lvp floor might encourage movement and the planks to disconnect and gap. I would love to add additional padding as this is a basement installation and the floor may be cold, but it may not be good advice to do so.

I just wanted to know what experienced experts here thought.

 

If the flooring has a backing on it you shouldn't NEED an additional underpadding. Now to look at the issue of it being in a basement and the floor being cool.
This is a product we have used multiple times in basement finishing to warm the area.

https://www.homedepot.com/p/DMX-1-ST...Step/204494289

Installing this , taping seams, and then laying 3/4" tongue and grove sub flooring over followed by finished flooring will drastically improve the warmth of the basement, as well as prevent water damage to flooring from minimal water infiltration. Again used multiple times in the midwest, MN, IA , SD, ND, WI. All with great results.

 

There are a lot of questions that come up where the end user wants to do something clearly different than what the manufacture states, we all have a hard time with that when the first response is "what does the manufacturer state".

So now we know more, it was the salesman not the manufacture who made the comment. So back to default response, what does the manufacture state, they are the ones who set the requirements.

Also, the under pad/backing is not the same as the under layment which is for vapor management, again the manufacturer would be best resource if needed!

 

Thank you the replies. I appreciate it.

I will add the additional layer of underlay (pad).