GKEYS55 said:
Be sure at the very least that is is an underlayment grade luan . What most dont realize is that there are several grades ,and out of all of them ,very few are underlayment quality. The difference being the glue used to make it.
Your best bet is to use a subfloor that is recommended by the manufacturor of the VCT going in.
That being said, just be sure that the floor your going over has been scraped of all the sheet rock mud and such and swept good.
I use 1 1/4" long 1/4" crown,underlayment staples. Every 4 inches or so in the field and every two inches at the seams. Be sure your compressor is set right so the staples countersink without blowing through. And please pound any in that did not sink!
Keep your seams tight and cut tightly around door casings and showers and the like.
Be sure to use plenty of staples,because to be quite honest ,luan isnt the best underlay for VCT. You dont want it to move or flex at all.