Probably want to follow the underlayment instructions for the underlayment. Can we get what products you are using to help us make better judgement?

"The flooring instructions call for the underlayment to extend 3-4" up
the wall and be trimmed before adding baseboards. The underlayment
instructions call for the perimeter to be kept 1/2" to 3/4" away from
the wall."

I am trying to understand those two sentences. If you meant the flooring instructions call for the perimeter to be kept 1/2" to 3/4" from the wall, that makes sense.

Evidently, the underlayment is designed to wrap the room and extend up the wall almost the height of the base molding.

The flooring needs that 1/2" to 3/4"{ gap around the perimeter to allow for expansion/contraction due to humidity/temp change.

So, install the underlayment so it extends up the walls on all sides, and the flooring over than with the gaps.

HandyMac, I think the OP is saying that the flooring instructions call for the underlayment to extend up and under the baseboards, but the kind of underlayment that is being used doesn't have the same instructions. Maybe they should be using a different kind of underlayment that is specified to extend up the wall? I would be pushing for the underlayment that is specified to go with this particular flooring.

Thank you all for your input.

Vith - The materials are Armstrong Performance Plus wood flooring and Quiet Walk underlayment.

HandyMac - If you are confused, you're reading it correctly! The installation instructions for the flooring call for the underlayment to extend up the wall (and trimmed down later) but the installation instructions for the underlayment call for it to have a perimeter gap similar to the expansion gap used for the flooring.

jellytoast - You've answered the question I probably should have been asking. Thank you. In the weeks that we have been fighting this, the installer's excuses, arguments, and claimed incomprehension have worn us down to asking for only very specific, warranty-related corrections that we can back up with documentation. We need to be "nitpicky" and "demanding" and insist that he use a more suitable underlayment. Thanks. Any tips on dealing with obstinate installers that seem to pride themselves on knowing better than the manufacturer's instructions, common practice, and laws of physics? :)

You're over thinking this.

The main idea behind having the underlayment ride up the wall and then to be trimmed later, is while installing a floating floor, which includes all the running around one can find themselves doing during the act of installation the underlayment can shift, and by having it ride up along the wall, and then trim it later, you ensure that every square foot of the floor has underlayment under it.

install the underlayment wall to wall. trim if necessary as you see the need.

I looked up both instructions and they do differ. I assume the Quiet Walk might not be suitable to bend and run up the wall so I would follow it's instructions in this case.

Perhaps the installer has used this underlayment successfully and it's produced many happy customers. I might do the same thing, albeit after presenting a case on why it's preferable.

What other issues are you having leading you to say that you're "trying to get a very bad installation corrected"? Asking a question about underlayment, which is installed early in the process, would indicate that the installation isn't done yet.

Hi, jfcwood. Thanks for the insight. That makes sense especially since the Quiet Walk seems fairly thick. It did occur to me that this might be one of those things that everybody does in spite of the manufacturer's instructions and it works out fine. I can't give these guys the benefit of the doubt though.

We are having this flooring installed on two floors of a house that is still under construction. At the time of my original post, the first floor was maybe 50 sq ft from completion and the crew had taken a break for another trade to come in. We saw issues with the expansion gap of the wood and a few other things and brought them up to the installer. He sent us a list of excuses and told his crew to complete the installation ASAP. They even had someone there on 4th of July installing baseboards on any wall with flooring even though that was supposed to be done by another trade. We now have the following list:

• The underlayment is cut into pieces ranging from about 6"x12" to 2'x4' and laid on the floor in a patchwork pattern that leaves gaps averaging about 1/2" all around.
• The underlayment touches the wall in some places and is 3" away from the wall in others
• The overlap edges of the underlayment have been cut off of some (but not all) of the pieces and none of them are taped - despite the underlayment itself being printed with instructions in three languages to tape the edges. Of all of the debris strewn about the house there is not a single roll of tape or empty core.
• The wood has an uneven expansion gap won't be covered by the baseboards in a couple of places and touches the wall in many places. The wood has been butted up against the exterior doors, wedged into each corner, and touches the lengths of the walls at random intervals.
• The wood is installed at a skewed angle that is not only unattractive but the narrow taper of the edge pieces is already shifting and allowing neighboring pieces to loosen up. The installer blames the builder for crooked walls but the walls are parallel to about 1/2" over a length of about 20' and the skew is the same at each wall.
• Each room has one or two prominently placed split or mismatched planks. I am not expecting perfection from mother nature but I am expecting the installer to discard these or use them in less conspicuous places.

Thanks for asking - ha ha! I really need advice now on how to handle this without going to court.

Hi, snookums2. Thanks for the good advice. We want to have documentation for everything so we reached out to the manufacturer via email and social media but have not gotten a response yet.

I really need advice now on how to handle this without going to court.

Probably not going to happen, but if this helps any, you can get a quote from someone else to fix the floor (listing detailed problems with the current floor) then take them to court. Shows them that another professional recognizes there are issues that need to be addressed. Another idea is you could get an independent flooring inspector to look at it, but there is a cost in doing that (depends on the floor cost if it is worth it).

The way they tried to throw baseboard on and run away shows they for sure will not work with you. Hopefully nothing else is wrong with the house.... :\ Might be worth having your house inspected, if they cant follow the directions with the flooring then what else did they mess up....?

I do think a small claims court judge would recognize that you questioned problems halfway through install and they tried to put it together fast and get out. Proving it is a different story.