Allure Ultra underlayment over concrete basement

[Carlos Nunez]

Hi All! I am finishing the basement in my rental property and am going to install Allure Ultra planks. Please can you share any experience installing a underlayment to help with imperfections and or help with insulation in cold temperatures? Also, have any installed in a concrete basement floor that wasn't 100% leveled?

I have a small gap and minor change in slope in the concrete basement slab (1 degree slope difference based on iPhone tool). It have considered a concrete leveled but because I am not finishing the entire basement and some rooms have a lot of items (washer, dryer, shelves), I hope I don't have to pour this.

Input will be greatly appreciated. Thanks in advance