The Dark Side of Polymer Crown Molding?
Monday June 29, 2009
At About Home Renovations, we get a lot of super comments on blog posts. But one comment really made me sit up and take notice. This was in relation to a short piece we did called 3 Reasons to Use Polymer Crown Molding Instead of Wood. In it, I trot out the usual things about how plastic crown doesn't split, doesn't shrink, etc. The comment from L. Riddell made some sense:
Installed the polymer crown moulding in my wifes office, and with the winter and summer temperatures changes the joins which were almost invisible in the summer opened up at least 1/4 inch or more in the winter. Had to remove it all in a year or so because my wife couldn’t take the smell that continually comes off it. Very noticeable if you leave the door to the room closed overnite. Never again. — Wood Only.I've been trying to find more information about the smell and possibility of shrinkage of these plastic crown moldings. And even though I haven't found anything conclusive yet, I certainly don't doubt the reader's comments. Fresh polyurethanes can really reek. One possibility: the moldings were not painted? A layer of primer and another of paint probably would seal in the smell. But that doesn't explain the shrinkage that the reader mentions.
Any readers who has experiences with poly crown moldings, please leave a comment!
Image of Polyurethane Crown Molding Copyright/Courtesy The Home Depot
Comments
I work for Fypon, manufacturers of urethane millwork and PVC products. The story posting and inquiry has us a bit concerned for several reasons.
First, in the initial story, I believe you said there will never be a shrinkage problem with polymer trim. That’s not the case. You need to make certain you’re using the proper adhesive between all moulding joints and FASTEN the pieces properly according to manufacturer instructions to minimize any potential for expansion and contraction. For that reason, many manufacturers suggest overcutting by a minimal amount before installation. Certainly though, urethane and PVC should not expand or contract to the same extent as wood when following installation instructions.
As for the odor, I have never heard a complaint about this at all in the 13 years I’ve been working with the company. I know of friends who can go on vacation and close up their house for weeks. They have an abundance of urethane millwork pieces on the inside of the home and there’s never an odor or smell when they return.
Is the person making the inquiry certain it’s polyurethane they used? Could it be polystyrene? That product is often used for interior mouldings and may react differently.
I hope this information helps. Seems like the product in question may not be a urethane product at all. I would also recommend if anyone has questions on this or anything else with urethane millwork, that they feel free to call the Fypon customer service representatives at 800-446-3040.
Thanks for letting me share some thoughts.