I need to replace some trim boards, end grain soaked up water…….
I’ve been thinking about cellular PVC. Doesn’t rot, holds paint well – any drawbacks? Southern N.H.
Preferences between Koma or Azec?
Thanks in advance.
I need to replace some trim boards, end grain soaked up water…….
I’ve been thinking about cellular PVC. Doesn’t rot, holds paint well – any drawbacks? Southern N.H.
Preferences between Koma or Azec?
Thanks in advance.
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Replies
I've used lots of Azek. The only thing you'll have to get used to is that the boards are floppy and need plenty of support when you're cutting them. For the same reason it's a lot easier to have an extra pair (or more) of hands when installing. Premade cornerboards are available if you are replacing those.
Never used Koma but it looks almost identical to Azek. You'll have to decide what to use as fasteners ie. screws vs nails, what gauge, and what to do about filling the screw/nail holes. There have been many threads here discussing those topics.
I'd say go for it!
Thanks for the info. I'm leaning strongly in that direction. Wood is good but I'm tired of dealing with the upkeep issues. Anything that will hold paint better and still look good has my vote for exterior applications.
Regards,
Saint
Good stuff. Hanging it is a bit different, tho'. FWIW, most lean towards SS trim screws.Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
Don't know anything about Koma.
Used plenty of Azek - good stuff especially in situations like you describe - doesn't soak up water.
Read all of the directions before you install it - website or manufacturer's brochures. There are some subtleties and good advice.
My preferences:
SS trim screws to hang.
Plenty of support behind.
Azek's own glue seems better than PVC pipe cement, equally as strong when cured but the Azek glue is "position-able" for a much longer time - more forgiving although we are still talking about being able to move the joint for 1 minute with Azek glue vs 10 seconds with PVC. Dry fitting is highly recommended.
I pin glued miters with SS 16 ga nails - the nails just serve to hold the miter while the glue cures - once cured the nails do nothing.
I like the Azek filler for screw holes, but I wait until all fasteners are in place on the project before filling - never had any real good luck with the "keeping" properties of their filler once opened.
The dust from sawing / routing looks like snow, comes complete with it's own static charge, will go / stick everywhere and lasts forever. The more you can do for dust control during cutting the better.
Jim
Hi,
Any problems with the miters opening once glued? I ask in regards to the expansion issues I've heard regarding PVC.
Thanks,
Saint
Azek is subject to thermal expansion equally in all directions, so miter joints don't open the way wood does, but long pieces grow considerably in length. Wood moves due to moisture, swelling/shrinking across the grain, but not parallel to the grain, so miter joints open at the outside upon expansion and at the inside upon shrinkage.BruceT
Securely screw-off and glue ALL joints. Butt, scarf, all.
You should not have any problem if you do this.
Seacoast of NH here, I am just finishing up a bunch of window trim kits that I pre-built and hung on new installs. This was my first time using PVC(KOMA) cuts like butter very easy to work with, yes it is "limp". My goal is to leave it unpainted as my trim package is white with cedar shingles... Also bought a sheet of AZEK 4 x 8 x 1/2 for some wrapping on a deck, I could not tell the difference between the 2 products. I know on the 5/4 I got 20' for less than the cost of a 18' azek. I beleive net was $58 for a 5/4 x 5 x 20 if that helps. Selectwood in Portsmouth stocks most sizes and has a price list in there catalog....
I've been thinking about using the sheet stock for wrapping my deck also. Seems like a perfect application. You happy with the results?
Saint
The big thing to be aware of with Azek or Koma, or other PVC trims, is they move a lot with temperature changes. I've had scarf joints that were tight at 80 deg., open up to 1/4" or more at 30 deg.
I've learned to glue EVERY joint, and overnail near the joint to minimize movement at the joint. Also, springing the board a bit helps, as does keeping the length down, when possible. Nothing will stop it from moving, but these help keep it to a minimum.
Finish nails don't hold well enough for PVC trims. I use either SS trim screws, or some kind of ring shank nail.
And I use Azek because its what my yard carries LOL
Shep, are you screwing off on both sides of your scarf joints? That should prevent movement.
From my understanding, the Azek brand glue is actually made by Gorilla Glue now. It didn't used to be. The original Azek glue worked very well and seemed like a nice product.
Well, that was until we all realized that none of us had any fingerprints anymore. They made the change shortly after we reported that. (At the time, Azek was using our jobsite for photos for their ads. Also, we were working with their reps on learning how to bend it for a catslide roofline.)
Any need to predrill prior to driving screws?
Do you use glue in addition to screws to bond to the sheathing / framing?
Saint
No need to predrill.
Glue only needed on pvc joints.
It would probably do you some good to study upon Azek installation.
Try the search function here.
Or try Azek's webiste.
I do now.
Fortunately, I experimented on my own house when I first tried Azek. So all the open joints are here for me to see every day as a reminder <G>
One of these days, I'll get around to dealing with them.
Both are good products, I've been leaning towards Koma lately because that's what the yard here stocks.
Need to recognize that it moves in both directions as temperature fluctuates. In the summer, I like to keep it in the shade until time to nail it up. Don't nail/screw to near an edge or it can crack. SS trim head screws are good, but not square drives, they strip out very easily. I use GRK (or similar) with Torx drive heads. Or nail with ss ringshanks.
Hi,
Thanks for the tips - I'll keep them in mind
Regards