One, Two, Three, Floor! Underlayment?

January 18, 2010 8:00 AM

We're putting in a laminate "wood" flooring in our kitchen. I've read this thread for great tips. However (underlayment question)...

...will we really need to add underlayment?

Here's why I think we won't have to: We'll be installing the floor on top of an existing linoleum floor that's in fine shape (just ugly) and we have no concerns about it, either for its durability or its "bounciness." Does this existing level of flooring address any reason we would have for installing the underlayment?

What would be any downsides to skipping that huge step/cost?

My understanding is that the underlayment is to allow the flooring to "give" a bit during a new installation over bare plywood, and to provide a moisture barrier. So I'm thinking my existing flooring accounts for that - is that too optimistic?

FWIW I am a competent DIYer, but have never done any flooring. Located in the Northeast.

posted by carlh to home & garden (10 answers total)

I helped my ex-FiL install one in their kitchen, over existing vinyl flooring, and we still used the thin-foam-sheet underlayment. One of the biggest things it does is help to compensate for irregularities in the smoothness of the floor, and yes, a little padding. The floor that's there is not really all that soft. Honestly, I don't remember it being all that expensive or time consuming.
posted by pupdog at 8:37 AM on January 18, 2010

While underlayment is important for the moisture and padding reasons, it's also important for it's sound-deadening qualities, especially if there is a room below your kitchen. I don't think linoleum would help with that. I would, however, check with the manufacturer of your laminate to see if installing it without underlayment would void your warranty. For example, it's optional with Pergo (what we used), as long as you're installing in a strictly dry area, which your kitchen would NOT be.
posted by deadmessenger at 8:53 AM on January 18, 2010

Are you talking about sheets of 1/4" plywood/waferboard or something more like rosin paper or the rolls of foam?
posted by electroboy at 9:03 AM on January 18, 2010

What does the laminate flooring product call for as far as underlayment? Their recommendation may have warranty consequences if the installation fails down the road. The linoleum as underlayment will be structurally fine but it might be noisy. What will the new flooring do to the height of the floor if you don't remove the linoleum? One reason to remove old flooring is to keep the floors level between rooms. Removing the linoleum and adding a 1/4" of the proper underlayment may be more costly now but satisfy two potential problems.
posted by birdwatcher at 9:24 AM on January 18, 2010

Thanks for the replies!

The kitchen is over our seldom-used garage, so I'm not concerned about a noise damper.

I hadn't even thought of the warranty on the laminate being affected by the absence of an underlayment. I will have to look in to that. Our current top picks are a flooring by "Surface Source" and one by "Swift Lock." They were both sold near underlayment rolls but nowhere did it say "don't forget, you totally need underlayment!" We haven't actually purchased material yet so I don't know what it says inside for installation recommendations.

From reading the above replies would it be safe to assume along the lines of "Yeah, it's probably better if you did replace linoleum with underlayment, but it's not going to be the end of the world if you don't." ?

I now realize I ought to check out the packages more closely and investigate that warranty issue.
posted by carlh at 9:57 AM on January 18, 2010

I don't know that you HAVE to take up the old flooring, as long as it's not going to make too big of a height difference changing to the next room. We were told at the time that the foam also helped the new floor keep from squeaking/rubbing against whatever was under it so loudly.
posted by pupdog at 10:18 AM on January 18, 2010

Pupdog has it - the underlay foam isn't to dampen noise from another room, but to prevent noises caused by the floor squeaking against whatever it's been laid on, when you walk over it. And to cope with small irregularities between the two.
posted by dowcrag at 10:27 AM on January 18, 2010

Some laminate has the foam backing already attached and all you do is roll out some black vinyl for the vapor barrier.
posted by tamitang at 8:18 PM on January 18, 2010

Check on whether you need the vapor barrier or not. Laminate is pretty dimensionally stable, and unless you're installing it on a slab on grade, you may not need the vapor barrier. Also, a lot of manufacturers have customer service lines that you can call to get information on your particular installation. It's definitely worth a try.
posted by electroboy at 7:34 AM on January 19, 2010

For anyone who's made a favorite of this thread or reads it in the future, after I bought the laminate flooring it said inside the box (nowhere else) that most existing floorings including hardwood and linoleum counted as an underlayment.

Presumably this might not be the same for all brands and types, but apparently it was for this. Which was nice, because we had more or less decided to skip the underlayment.
posted by carlh at 4:31 PM on January 25, 2010