Concrete is 30yrs old and dry as far as I can tell. It's not 100% level. Floor guy says we don't need an underlayment but I think it's a smart idea. What sort of underlayment is ideal? Are there brands to avoid? Thanks for the insight!
Videos
Can underlay fix an uneven subfloor?
No — underlay cannot correct bumps or dips. It only provides cushioning and noise reduction. Using thick or multiple layers of underlay will make the problem worse and reduce stability. Levelling compounds, grinding, or plywood are the correct solutions.
Can you double up on underlay for laminate flooring?
It is generally not recommended to install a double layer of underlay for laminate flooring. This is because the base of the flooring may become too soft, thus jeopardising the effectiveness and reliability of the locking system. Underlayment is only manufactured to be used as a single layer. If you need to use more underlay for acoustic purposes, aim for a higher AAAC rated underlay.
You can also book a free on-site inspection with us at FloorVenue so one of our professionals can help determine the best course of action for your project.
What happens if you lay laminate flooring on uneven floor?
Laminate flooring on an uneven floor will cause many problems. One of the major problems are loud pops and cracks that will eventually surface when you walk across due to pockets of air beneath the surface as a result of the uneven subfloor.
Other potential long term issues include buckling, loose boards, and a significant shortening of the laminate flooring’s lifespan. However, slightly uneven subfloors are simple to fix with fast and easy solutions such as sanding down the bumps or using self levelling compound prior to installation.
Man I'm ripping up a lot of floors these months! I'm dealing with an incredibly uneven subfloor right now. Used to be carpet. Previous owner filled the most egregious valleys with floor leveling compound that's old and turning into dust. So i need to decide the following:
How to fix it? And then what to put down - laminate or vinyl plank?
So I can either hire someone to just put big sheets of plywood down across the entire floor. Generally speaking, if i do this, I won't need to otherwise correct the flooring right?
Or, I could grab my planer, my belt sander, and some levelling compound and do my best to level it out a bit.
In terms for flooring, I'm either doing cheap laminate or cheap ish LVP (it's a rental). The laminate is a bit more forgiving because i have an underlayment but for the vinyl plank if i remember correctly the floor has to be perfectly flat because you don't use an underlayment. The kind i used has sticky edges and you just stuck the edge of one piece to the edge of another.
I loved how easy the LVP was. I didn't need a saw! I'm terrible at a jig saw so even though I've done laminate before it's frustrating and any detailed areas don't look so great.
If i hire someone to put sheets of plywood down, do i still need to use floor leveler? If I use laminate, could I get away with planing down the worst peaks but leaving a bit of unevenness and getting a thick underlayment?
The floor comfort underlayment is to be used with laminate or engineered wood NOT LVT or LVP.
Go with the Smartcore and approved underlayment. I have used that brand and had great results. Better to use products matched to each other.
I'd use a 1/4" notched trowel with some stiff thinset mix. Trowel it on your floor surface leave the notches standing. Once stiff enough I'd fill the voids and flat trowel against the notches. This will bring your floor up the 1/4". A bathroom floor is so small and area it isn't that much work to bring it up 1/4".
Don't use another layer of underlayment, you can get too much deflection in the click lock system and break the tongues.