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Hey everybody. I thought I'd ask you trim pros your opinion on using pvc boards on an exterior project. I'm doing a full window install on an old brick home, and the homeowners have requested I use pvc trim (for the low-maintenance benfits). I'm casing the windows with 1 x 4 pvc boards, using butt joints, and dap (latex with silicone) caulk.

Any opinions on what size expansion/contraction gap is appropriate? I hate to sacrifice appearance for functionality, but am afraid the boards will buckle when it warms up in the summer. Has anybody had any success with this stuff? Thanks in advance. Ya'll have a lovely day
 

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KemoSabe
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I've done a little PVC.:whistling

You should definitely keep a minimum of 1/8" around the perimeter of the window, moreso if working with the material in warm weather, but a gap is advisable, always.

PVC will move substantially with temperature swing, especially in direct sunlight.

All joints should be glued, although long runs are prone to failure over time, especially if painted a darker color than white.:thumbsup:
 
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topsail's trimcat
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riz by a little pvc work do you mean 5 pallets worth of azec :whistling

we use it on every house for cladding the decks mostly especially on teh front. on odd situations with door and window build outs we use it there as well
 

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KemoSabe
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riz by a little pvc work do you mean 5 pallets worth of azec :whistling
10 pallets would probably be more accurate, but I haven't been counting.:laughing:
 

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Like others said....Glue joints tight and leave a gap agaist the window. Prefabing the trim is a great way to go and pocket screws work great for that process. Sometimes I use my Senco Senclamp for fast pre-fab. For PVC glue I LOVE Bond&Fill Structural slow cure or TrimBonder. Both make a structural bond and are white, sandable/scrapable, gapfilling, easy cleanup, etc. I also use the Azek glue with good results but I hate the dauber application.

I use Fastenmaster Cortex on any job that will not get painted. Painted jobs get SS nails and a few Cortex.

You mentioned Dap caulking... DON'T use the regular Alex's $2 a tube crap. It is not elastic enough. At least use the Dap Dynaflex or equivalent if you prefer water cleanup. I really like to use Duo-Sil sealant on all PVC work. There are alot of decent sealant options. Unfortunatly there are more choices that are NOT appropriate for PVC but people use them anyway.
 

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KemoSabe
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Anyone ever heat azek up for bending? I did a whole bunch of crown in some circular tray ceilings with it. Worked great.
Only time I heated it was to make a 12" radius on the flat with 5/4x6. Worked great, but heat blankets would have been the bomb.

Most cases, I'll use a router and trammel and cut out of sheet goods.:thumbsup:
 

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Finish Carpenter
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Anyone ever heat azek up for bending? I did a whole bunch of crown in some circular tray ceilings with it. Worked great.

How tight of a radius did you get from it? I need to crown a bathroom with some 3 5/8" col crown that has 12" radius corners...was thinking about using Azek.
 

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TRADE CRAFTSMAN.
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25 yr exp. & still learning.

I've only used PVC trim once. I installed a dental work under eves of a new home built in a 1850 farm house style I thought it was a little hard to work with but man did it look cool & a whole lot faster than fabricating my own.:thumbsup:
 

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Working
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On the note of failing glue joints on long runs. They are jagged edge, not a smooth break. SO on long runs I don't glue one joint.

Cole
 

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How tight of a radius did you get from it? I need to crown a bathroom with some 3 5/8" col crown that has 12" radius corners...was thinking about using Azek.
The tightest radius I did was about 5ft. 12" might be pushing it but I think it would work. I used 5 1/2" crown so 3 5/8 should be even better. What I did is used cone geometry witch takes in to account the angle of the crown from the wall and the radius of the wall and gives you a radius to bend the crown when laying flat on the ground witch is much less of a radius than the wall it self. So then you make a jig to bend the crown to, witch would just be a piece of 3/4 mdf with the radius cut/routered out like you would if laminating a casing blank. Your radius might end up as much as 3 or 4ft. Heat up your casing and bend it to your jig laying flat on its back and let cool for about 10 min. and your good. Give it a shot I think it would work great.:thumbup:
 

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topsail's trimcat
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our biggest azec project was on a 1.2 million dollar complete reno a couple years back, all new cedar pre finished cedar shingles and all exterior trim in azec, roughly $40,000 of azec alone i believe
 

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KemoSabe
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What did you use to heat it up.
I used a heat gun and wrapped it around a form. It was very slow and hard to get it heated uniformly. Without even heat it doesn't like to bend neatly and tries to "egg" out.
 

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topsail's trimcat
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good to know riz, on that big one we simply tried slowly bending it by driving ss screws every foot or so. we had a couple pieces snap.there was a few turret windows and a large round room for which we had to put fascia up on as the radius was also on the outside
 

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I was heating up 18' lengths so I used 12" metal ductwork pipes about 20' long. Made a wood grill plank to lay the crown on and slide in and out of the duct. Then I used a large torpedo heater to blow through the duct from about 2' away so as not to start a fire (learned that the hard way) To heat it evenly I swapped the heat from one end to the other half way through the heating time. Worked really well.
 

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Like others said....Glue joints tight and leave a gap agaist the window. Prefabing the trim is a great way to go and pocket screws work great for that process. Sometimes I use my Senco Senclamp for fast pre-fab. For PVC glue I LOVE Bond&Fill Structural slow cure or TrimBonder. Both make a structural bond and are white, sandable/scrapable, gapfilling, easy cleanup, etc. I also use the Azek glue with good results but I hate the dauber application.

I use Fastenmaster Cortex on any job that will not get painted. Painted jobs get SS nails and a few Cortex.

You mentioned Dap caulking... DON'T use the regular Alex's $2 a tube crap. It is not elastic enough. At least use the Dap Dynaflex or equivalent if you prefer water cleanup. I really like to use Duo-Sil sealant on all PVC work. There are alot of decent sealant options. Unfortunatly there are more choices that are NOT appropriate for PVC but people use them anyway.

How do you like the senclamp? have you used a corragated (sp) fastener tool also? Which one works better?
 
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