first question – Koma website says leave a 3/16″ gap over 18′ to allow for expansion/ contraction and they also say glue all joints with pvc cement. one or the other. I plan to use 1″ x 4″ around all doors and windows (28″x36″ up to 36″x54″). how much contraction will actually I see after summer installation?
second question – I hope leave white/ no paint. local hardware store has white headed nails, or use dab of caulk filler? what seems to look best after a few years? site is coastal NC.
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We have been using white silicone to fill the nail holes.
what about the gap, do you leave one at the corners when framing a window?
cat, the couple window/door casings and built up columns I've made out of Koma and Azek, I glued the joints together. Used azeks pvc cement and reg. plumbers pvc cement. For long joints like columns, I'd use the Azek-a bit longer positioning and set time. More expensive by a long shot, but more clear and forgiving.A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
Quittin' Time
i believe I've seen filler sticks for PVC trim, though I don't remember who makes it
i don't think the expansion gaps they are referring to really apply when casing doors and windows...more for running long lengths of trim boards..and i don't think the HOs would be pleased to see gaps in the corners of their window trim..
as for filling the holes...my first thought would be to try and glue everything and avoid fasteners..if thats not possible, could u make some plugs out of the pvc stock?i work with a lot of solid plastic lumber for decks/railings/etc...we use a drill press and make plugs, and when finished u can hardly find where the fasteners are...i dunno how well pvc lends itself to plugs, but just a thought...
i never feel good about using caulking/silicone to fill holes...
Edited 8/13/2006 12:53 pm ET by matasky
and I've heard that the 'shades' of white caulk are hard to match, I'll try some plugs, sounds reasonable if I have to use large screws. the white-headed nails don't actually look too bad
I used Koma board at 1-1/16 inch, 6inches wide as corner boards on a job 'bout 5 years ago. Corners about 24 ft. tall. glued all joints tight. hasen't moved yet. Don't know about filler, plugs sound like a pain. Vinyl spackle? We tried several dii. fillers, they all shrank to some extent. Jim Devier
but even the cornerboards need to be attached to the house at some point with screws or nails, and I'm trying to cover up those holes. I'll certainly be forming our own corner boards (local supplier asks almost $100 for a 4"x4"x20' premade corner!) with the PVC cement, probably ought to use the expensive cement because it is much clearer?
Cat, as I mentioned b/4, I would spend the $'s for the azek cement where a slightly expanded assembly time was necessary. Most any slop can be sanded off, so for quick glueups the reg. cement seems to hold. (do not slop if possible)A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
Quittin' Time
Like you I didn't want to paint some of the mat so we carefully applied a little bit of vaseline either side of each joint before glueing. any ooze came off when we washed off the vaseline. Jim Devier
I've ordered and installed a number of exterior doors with pre-applied cellular PVC trim (5/4x4 Azek). It was all butted tight. No problems after a few years. It was all painted.
On one project I used vinyl spackle on the nail holes but that ended up needing to be sanded and the result, although flush, was prominent spots in the plastic boards that had a different texture. These disappeared once painted though. On that project some of 1x4s and 1x6s were used at their full length, butts were glued with Azek glue, and, to reduce the number of nails needed, it was all glued in place with poly construction adhesive.
Re the nail holes that won't be painted, I'm starting some vinyl houses that will have a few cellular PVC trim boards "up high" on them. My vinyl guy tells me he is going to use white silicone caulk on the nail holes and then rub off the excess once it is dry. The idea is to keep the houses as low maintenance as possible.
I wouldn't use regular PVC cement on anything that won't be painted because it yellows over time. Use what the manufacturer sells. The extra $5 or $10 will be very small in comparison to the cost of the PVC "boards".
I think the bottom line though is that if you want to use cellular PVC exterior trim un-painted you will be in a "don't look too close" kind of situation.
Edited 8/14/2006 7:25 am ET by Matt
i have yet to use the pvc materials, like azek, but is it alright to paint them?
doesn't seem like pvc would hold paint very good, but if they say u can....
I thought the same way you did, however it does hold paint fine. I think they recommedn 100% acrylic latex but you might want to check with the manf's web site