So your client goes to the home show and sees this new decking material that is either cheaper, or more durable, or more ecological, or fancier or simply exotic and they want you to install it. So you check out the literature on it and they all say that you can work with their material just like regular wood. Of course you don't believe it. They all want to be the easiest material to work with since sliced bread so none of them want to admit to their learning curves. Have you ever found any new material that didn't require some kind of learning curve?
When I talked to the manufacturers, there were no problems. When I talked to a few installers, there were some tricks and tips, though no serious problems. When I talked to the saw blade manufacturers, they didn't have a lot of experience with much of this stuff.
Here are some of the basic tips that we managed to get out of site reality.
Most of these new materials are some kind of plastic or partially plastic moldings or extrusions, which means that they have no grain and are tough on blades. Carbide is essential, but I don't know anyone who is not using carbide. What may surprise you is that finishing blades don't do too well in the massive types like PermaDeck and Trex as they tend to over heat. 22 or 24 teeth is recommended here. Cut at a moderate speed. Too fast will cause chatter, too slow will begin to melt things.
On the other hand, when cutting vinyl or fiberglass extrusions that have thin cross sections that can get into vibrating and catching, 40 teeth does the job better. In fact, a blade like the Freud Diablo that has a very thin kerf and anti-kickback rakers is going to give the 7-1/4" circular saw the type of cut that a triple chip blade will give from a table saw. The triple chip works by having three different teeth strike in sequence to make one full kerf cut, eliminating shock and chipping by spreading out the attack. The Diablo has a very thin kerf and the rakers won't allow the blade to move in for more than a scraping bite - accomplishing the same fine cut with a portable tool.
I couldn't get any feedback as to whether a Teflon coating on the saw blade, which works wonders in sappy pine and spruce, helps any with these plasticized decking materials. If you've tried it, please write in and let me know.
One thing for sure is that all of these materials, including Nu-Forrest's real wood Brazilian Hardwood "Paulope", are tough on blades. Count on re-sharpening at least two blades on every deck.
None of these materials accept nails well. Use screws with pilot holes and counter sinks, or proprietary fastening systems that come with specialized materials, or if you are investing in an expensive top, try Deckster brackets to screw them down from underneath.
Remember that with no grain, most of these boards are relatively flexible and installing them straight requires many more spacer shims than real wood, as long lengths will wave left, then right and back again.
**Originally published as an article by Jon Eakes in Home Builder Magazine, the magazine of the Canadian Home Builder's Association.