replacing wood trim - wood choice ? and priming ?

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Old 09-19-10, 07:05 PM
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replacing wood trim - wood choice ? and priming ?

I am going to be replacing the wood trim that is rotting on my bay window and had a couple of questions.

After talking to a neighbor, he suggested not replacing with the same cheap pine board, but a better quality wood (like poplar) or the Tuffboard. I have some concerns about replacing the trim with the Tuffboard because if I do have a water problem, I won't have rotting trim to let me know. The poplar would be more rot resistant and hopefully last longer than cheap pine board. So should I go with better wood, or is the pine board just fine?

Now about priming. Is there any benefit to priming the entire piece (front, back, and edges) prior to putting the piece up? I was planning on getting the Zinsser (sp?) cover stain primer, and have acrylic latex exterior paint already from painting other pieces of trim.

Hopefully I don't have a water problem and that is the cause of the rot. I have a feeling that the painter I hired a couple of years ago to re-paint the bay window took some short cuts and didn't caulk (or re-caulk) very well, so now some wood is rotting and I have paint peeling in some spots. So I am going to replace the trim (as much as I can get to), inspect underneath while I have the trim off, and prime and paint and caulk (clear silicone is my choice of caulk).

Since this is a bay window on the second floor, hope to also check out how good (or bad) the insulation and air sealing is in there before getting the outside looking all pretty again.

Thanks,
Neil
 
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Old 09-19-10, 07:18 PM
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By "wood trim" I assume you are referring to exterior trim, not interior trim. Hopefully your interior trim would not be getting wet.

You don't want to use poplar, it's not a good choice for exterior wood since it is soft, related to the cottonwood. Poplar is a nice choice for interior trim, but not exterior trim.

Clear SYP (southern yellow pine) or cedar is probably your best choice for any exterior trim. Yes, you definately would want to prime and paint all six sides of each piece of wood if you wanted it to last the longest. There are also wood epoxy resins that you can paint onto bare absorbent wood to help extend it's longevity. Don't know anything about "tuffboard" but I have used Miratec and LP SmartTrim and like them. But I don't trust those products if I have to rip them down and have exposed edges that aren't factory finished.

Azek PVC trim (or similar) would be your best choice if you wanted something that would never rot.

You definitely do NOT want to use 100% silicone as an exterior caulk on siding and trim unless you are using a "siliconized" latex that is paintable. A fine bead of clear silicone would only be used to reglaze the wood to glass joints as needed, and would never be painted.
 
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Old 09-19-10, 07:44 PM
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X,
Yes, it would be the exterior wood trim.

I saw the southern yellow pine at HD. Is the poplar really that bad a choice? I already got a couple of pieces of the measurements that I knew off-hand.

I was thinking that the silicone caulk was the way to go since it would not get hard and dry out? I knew it wasn't paintable,but wasn't too concerned since the caulking would be on the second floor and I would paint first, then caulk. I don't recall seeing a painting silicone caulk at HD.

Thanks for any tips/advice.

-Neil
 
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Old 09-19-10, 07:53 PM
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Poplar is like a sponge for water. When used for exterior purposes, it gets moldy quickly for some reason, even under a coat of paint. Not sure what it would do if you saturated it with some of the rosins that are out there.

SPF (spruce / pine / fir) has a high percentage of sap that naturally resists a certain amount of decay, whereas poplar's sap is about the consistency of water- nothing like pine tar.

When the house and/or trim needs to be repainted in 3-7 years you might wish you hadn't used 100% silicone. GE Silicone II is a paintable silicone. Otherwise look for siliconized acrylic.
 
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Old 09-19-10, 08:10 PM
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Thanks for the quick reply. I'll see if I can return the poplar (even though it was cut...).

I just checked and I actually bought the GE Silicone II. It says it is 100% silicone, but I don't see anywhere on the tube about being paintable or unpaintable.

-Neil
 

Last edited by stickshift; 09-12-13 at 11:52 AM. Reason: removed quoting of entire post
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Old 09-19-10, 08:19 PM
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I guess there is some GE Silicone II is not paintable... the stuff I was referring to is paintable Silicone II that will specifically say so.
 
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Old 09-20-10, 05:33 AM
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I'm sure XSleeper knows more about the different woods and there applications than I do but I have painted numerous houses that had poplar siding. Whatever species of wood you use, be sure to use a good oil base primer. If you use cover stain - make sure it's the oil base one. I'd prefer a good exterior wood oil primer like SWP's A-100 oil base primer. Latex is usually best for the top coats.

Back priming the wood can also help. Personally I wouldn't use a non paintable caulking. Most of your better latex caulking are fortified with silicone. Look for a siliconized acrylic latex caulk. While a pure silicone caulk might adhere better/longer, it will still present a problem when it comes time to repaint, it will also attract dirt because of it's softer tacky finish
 
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Old 09-20-10, 07:08 AM
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I have never ever seen poplar siding- so I did a little "Googling". It sounds like the "poplar" used for siding is mostly "tulip (yellow) poplar", not aspen (white) poplar, which is what I am most familiar with as interior trim wood. You would probably not want to use aspen poplar as exterior wood. Yellow poplar and white poplar are not related, species, despite the name.

Even so, I found one source that recommended white pine over tulip poplar for exterior uses.
 
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Old 09-20-10, 09:35 AM
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X,
I did some googling too and did not find anything positive about poplar for exterior trim. Hopefully I can take the few cut pieces I have back to HD, or I'm out $30 (or maybe I just created another woodworking project for myself ).

I am going to try and check a local 84 Lumber to see what they have, but their hours around here are very short (compared to HD and Lowes), only until 6 pm (can't get there because I work until 5:30 or 6 everyday) weekdays and 8-12 Saturdays.

I did find Western Red Cedar on Lowes' website, so it may be available locally. I always though I have heard that cedar is good for exterior (decking,siding, etc.), so I would think cedar trim would be acceptable and durable.

Thanks,
Neil
 
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Old 09-20-10, 10:12 AM
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We use cedar outside around here (that and PT, of course)
 
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Old 09-20-10, 11:02 AM
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The only issue with cedar is the tannin bleed and as long as you apply a good heavy coat of oil base primer - that shouldn't be a problem.

When I lived in fla, there were a lot of problems with pine trim because it got some type of fungus that destroyed it Doesn't seem to be an issue here in east tenn. All the better homes in fla with painted wood, used cedar or occasionally redwood.
 
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Old 09-20-10, 11:08 AM
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ok, at the risk of soundng dumb, just want to make sure I have a few things straight before tackling this project.

Assuming I have my choice of good wood for the replacement trim (cedar), and I get a paintable caulk (silicone or siliconized acrylic latex), and back-prime everything (probably Zinsser Cover-Stain oil based primer), do I:

1. caulk then paint, or
2. paint, then caulk?

If 1, do I need to prime the caulk?

The paint color is kind of a dull buttery yellow. I doubt I can find caulk to match off the shelf.

And should I caulk all sides to completely seal everything up? Or leave the bottom uncaulked so if any moisture finds its way in, it can run down and out the bottom?

Thanks,
Neil
 
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Old 09-20-10, 11:32 AM
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It's best to prime first, then caulk. The primer seals the wood so the caulk has a better chance of staying somewhat flexible and the latex top coat will cover the caulking.
 
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Old 09-20-10, 11:58 AM
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for caulking I would highly recommend you avoid anything latex. The best caulk that HD sells for your application is OSI Quad. it comes in several colors and is paintable. you will have to wear latex gloves when applying, but it is far superior to latex caulk or any DAP product.

a polyurethane caulk like NP1 is even better, but try to find it at a local store...

note: OSI Quad may in fact be polyurethane, I don't know, it doesn't say so on the tube.
 
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Old 09-20-10, 03:23 PM
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ok, last question for now.

Caulking the inside corner joints is easy, but what about outside corner and butt joints? I have some outside corner (45 degree) joints between trim pieces, as well as horizontal and vertical butt joints. Do I just lay some caulk in the joint before installing the second piece, so it squishes into place inside the joint?

Thanks,
Neil
 
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Old 09-20-10, 03:27 PM
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Caulking before/during installation would likely give the best seal. I normally don't caulk until after the carpenter has nailed it up

If using latex caulk, a damp rag/sponge will make smoothing the caulk out easier. It also helps to keep your fingers cleaner A solvent based caulk would need a rag damp with the appropriate thinner.
 
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Old 09-21-10, 01:46 PM
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Originally Posted by XSleeper View Post
I have never ever seen poplar siding- so I did a little "Googling". It sounds like the "poplar" used for siding is mostly "tulip (yellow) poplar", not aspen (white) poplar, which is what I am most familiar with as interior trim wood. You would probably not want to use aspen poplar as exterior wood. Yellow poplar and white poplar are not related, species, despite the name.

Even so, I found one source that recommended white pine over tulip poplar for exterior uses.
XSleeper - I think this is another example of geographic differences. I have 3 huge tulip poplars in my yard. Years ago tulip (yellow) poplar was a very popular building material. That was in the days before western doug fir and the SYP plantations.

I agree with you that unprotected tulip poplar has a low rot resistance. If I were replacing exterior trim I would opt for a tight grained SYP over poplar simply becasue it's available and more resistant to decay.
 
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Old 09-21-10, 03:49 PM
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Yeah Wayne that was a new one on me. I think I've seen tulip trees occasionally, but had no idea they used them for lumber/siding! Seems like it is kind of a small ornamental tree when found out here in the midwest. Maybe our winters are too hard on them.

Yes, I agree that the tight grained heartwood is best. Much more dense and sappy.

What I don't get is why they call the tulip a poplar if it isn't related to other poplar trees that are "really" poplars?
 
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Old 09-21-10, 03:58 PM
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Originally Posted by XSleeper View Post
Yeah Wayne that was a new one on me. I've seen tulip trees, but had no idea they used them for lumber/siding! Seems like it is kind of a small tree when found out here in the midwest.

Yes, I agree that the tight grained heartwood is best. Much more dense and sappy.

What I don't get is why they call the tulip a poplar if it isn't related to other poplar trees that are "really" poplars?
The tree actually has what looks like a tulip blossom in hte spring. It's not a true blossom and there is a name for it but it escapes me right now.
I like southern yellow pine. Whenever ZZI get a sill that cracks I make the new one out of a piece of SLP stair tread. Most wood is just fine for exterior applications - as long as they are protected from the elements.
 
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Old 09-22-10, 10:00 AM
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Rockford, you want to leave a gap between the bay window and the trim board for a proper bead of caulking there. The two materials are dissimilar and react differently in their expansion and contraction with the seasons. If you butt them tightly, thinking that would be better, the bead will fail and allow water entry. The caulking requires a poly backer rod to control the shape of the bead on the back-side, in this application. Wipe the front side with a wet finger or rubber glove covered finger to get the optimum hour-glass shape for a quality, professional job.
http://docs.google.com/viewer?a=v&q=...X1IjstvXQPNoxA

Gary
 
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Old 09-23-10, 05:18 PM
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Alright guys, you have been a great help. Couple more questions since I now have most of the wood and primer. I ended up going with western red cedar since my other choices were red oak, poplar, or whitewood pine. Home Depot did have SYP, but only in tongue and groove boards.

Anyway, two more questions:
1. I have enough wood to do the trim below the window and along the bottom of the bay window. I may need to replace part of the vertical trim boards at the corners of the bay, however I don't have the equipment to get high enough to do the entire board (nor do I know anyone with a tall enough ladder, at least a 24 foot needed). It looks like there may be some rot lower down, so I was thinking of replacing the bottom part (I can get to the bottom half with my 18 foot ladder). What is the best way to cut out the part to be replaced and cover the new joint?
2. I was thinking of screwing the trim board in, but then decided to nail it in case I ever have to do it again. I have to check my nail guns, but what would be the shortest nail that would work? I know my nail guns can do 1-1/2" finish nails (came with them), not sure how big they can accept (I have a finish nailer and a brad nailer). Not sure if 1-1/2" is enough to get into the framing enough to hold the trim on good (assuming 3/4" trim board and 1/2" sheathing, only 1/4" into the framing).

Thanks,
Neil
 
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Old 09-24-10, 03:41 AM
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You don't want to use finish nails or a finish nail gun. You'll want to use galvanized nails with a head - it will hold better.

Have you considered renting a longer ladder?
 
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Old 09-11-13, 02:18 PM
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Poplar is like a sponge

I know this is a necro-post, but for those new to it, I use quite a bit of "Big Store" Poplar for indoor usage.

I often make frames with loose tenon mortise joints. When I use polyurethane (expanding) glue, the glue travels some 1/4 inch through the end grain in a matter of minutes, bubbling right out of the (end grain) side of the joint. Therefore I don't use this glue when that might spoil the finish (however, it does, I think, give me a pretty solid piece of impregnated wood for strength!

If glue gets through like that, poplar must really mop up water - I would not dream of using it in wet situations. I don't know about the other variety of poplar mentioned above, that might be OK but I have no personal knowledge.

For outside trim, if I want real wood, I'd use cedar, otherwise PVC.
 
 

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