There is a cup at the ends of cement siding but joints factory cut or field cut, Hardi Plank and Certainteed siding that can be seen when the sun hits the buildings. Should you caulk but joints and why does the cup show? If you caulk the but joints the caulk seperates after 6 months or less.
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A guess is unprimed cuts which allow water to swell the siding.
Oh that's just swell isn't it ?
Carpe that ol' diem ! ~LisaL
Hey, it worked! And it is SWELL!
first, i don't know if the but of that piece of siding was cupping to begin with, that cement stuff comes as straight as a ruler, possibly it was a bad piece from the factory.
also, hopefully there was a 1/8" expansion gap left between the two pieces where the joint is upon initial install, if not, when the planks expand, they may be "smashing" into each other. another factor is if the nails used were fastened through the planks into studs, this adds extra hold when fastening the planks, and insures they won't curl away from the house, hopefully this was done.
solutions:
-if there isn't an expansion gap, get a circular saw with a cement cutting blade, and cut one, then caulk and paint.
-if it keeps coming back, a last resort may be to sink an exterior nail into the "flap" that is cupping, along with a little adhesive on the back of the plank.....
don't know if this will help, good luck.
Always prime the edges before caulking.
Not exactly sure what you mean by cupping but I assume that you mean the butted together ends are protruding a bit and when the sun hits it just right it shows up more. I've built a number of houses with cement board siding and here is what I've learned: Hardi is not arrow straight nor will it necessarily lay dead flat on a wall, so, yes during certain times of the day, it doesn't look great. You get some of that with real wood clap boards too. Even though the Hardi literature says you can run the butt joints snug, always leave 1/16 to 1/8" gap - depending on the temperature when it is installed. It does expand and contract a bit so you have to allow for that. If your caulk joints are failing and you left enough of a gap for the caulk to get between the 2 boards, but not too big, you are using cheap caulk. I can't remember if my painters shot the first coat before or after they caulked, but I'm thinking they caulk first. I've never heard of priming cuts on Hardi.
Guess i shouldn't push the competition, but the issue of JLC I just got today talks about this--they say no caulk, metal flashing under, prime the cuts and butt tightly.
i read that... what a bunch of crap... JLC should be ashamed for promoting that
no way do butt ends swell up like his sample photo... something else is wrong there
and the "no caulk" ..... more BS... the guy is not a painterMike Smith Rhode Island : Design / Build / Repair / Restore
That's right Mike!!! You tell 'em!!!! :-)
Just goes to show - don't believe everything you read - even in the most reliable places...
We just did our first job with Hardi prefinished, and it looks pretty good. A sales rep for Hardi came out and answered our questions on installation. With the prefinished, Hardi is recommending no caulk at joints, just paper behind.The only caulking is at corner boards and windows, etc.
This came from the Hardi rep from Rhode Island.
Greg in Conecticut
greg.. i have a lot of problems with hardie reps... some of their specs are asinine
and that's one of them
i've talked to them at JLC.. they don't know their azz from their elbow
what kind of a job is it where the joints are not caulked .. what's the difference where the siding butts up against trim with caulk ?
and paper splines ? rediculous.. what good is a 50 years siding with 10 year paper splines ?
and they want you to keep their F'g product 2" off the roof ?
if they want to start giving their product a bad rep , they can certainly keep on keepin on with that jazz
frankly , no painter worth their salt would swallow any of that bunk....
i sure wish Certainteed would compete with them in my area.. i much prefer the Certainteed FC to the Hardie
but hey, whadda i no ?
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 10/13/2006 9:17 pm ET by MikeSmith
I read that 2" up off the roof stuff too in the destructions. How much do you hold the FC up off the roof? I go for 1".
I have never been able to figger out the 2" off the roof line thing either. We've always put it at an inch or so up and never had a problem. Also use a tin shingle behind the joint , quikest and the best no caulking is necassary, the stuff does not swell with water so I cant understand what the issue would be.
I knew a guy that chucked a piece of the Hardi lap siding in a bucket of water and forgot about it for a couple months. I saw it after it had been in there for about three months and the ends hadnt swelled a bit.
I know that 2" was the standard recommendation for Masonite tempered siding, but based on my experience 1" would do fine. You do want close to an inch, though, so that any leaves or other trash will not lay against the bottom edge of the siding and wick water into it. The 2" number could be justified in exceptionally "trashy" situations, or where wet snow is apt to stand against the joint.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
What's a "tin shingle"? Although I imagine it's just a piece of flashing? BTW - I have always wondered if FC siding could be corrosive to AL flashing...
BTW - I just reread the Hardie install instructions again. http://www.jameshardie.com/pdf/hardiplankinstall.pdf I also had a copy I had downloaded a few years ago. They had modified their recomendations as to how to treat the butt joints. Before they said "moderate contact" or space per caulk manufacturers recomendations. Now they say "moderate contact" with flashing behind OR gap and caulk.
From my personal observations of bad looking siding jobs, (puckered butt joints) I want it gaped and caulked, or I could probably go with the flashing (never tried it), but I'd still want a small gap to allow the FC material to move around just a bit.
Here is an idea..... someone needs to get a full length piece of FC and leave outside on a very cold day for a day or so. Now measure it very carefully - length and width - to the 1/32th... Then bring it into a fully heated area, for at least 12 hours. Measure it again very carefully - same tape measure (maybe even tape measure at same temp as before) and see if the FC has changed sizes. I don't have a pc of FC handy, nor would my DW allow a piece of siding in the house... :-)
Side note: one thing good in the updated above linked instructions is they have a picture showing a kick-out flashing. This is one detail that I notice some builders and siding installers seem not to understand how important it is, based on it being omitted. This detail applies to any type of siding.
I can do that experiment, I have a pile outside on horses.
I will tape it and see what the actual is.
Spheramid Enterprises Architectural Woodworks
"have the cold, comfortably numb"
For Darcy.
Cool! Is your wife gonna let you bring a piece in the house? :-) Let us know what happens.
we lay a piece of furring on top of the shingles and use the top as out scribe line
hey , the picture of the "bad swelling " in the article... i've never seen FC sidding do that...
i have seen some of the Masonite ( wood fiber ) siding look like that.. they were the losers in a class action suit
i don't think that was a picture of FC siding, and caulking the butt joints would not have any bearingMike Smith Rhode Island : Design / Build / Repair / Restore
Mike,
We are back to doing our own siding and I talked to Mark Parlee on the phone. He posts over at JLC and does a lot of siding. We talked about that 2" off the roof and out here we've always done 1". He said that back where he is at in the midwest, the 2" is necessary because when they get a freeze, water can freeze back up into the Hardi. He gets around that by running trim up the rake and landing Hardi on top of that.
He also recommended a caulking called Dymonic FC, which we ordered in and will try in a few weeks. We are also going to use slip sheets and not caulk the butt joints. I'll take pictures and let you know how it came out.
I flash the joint and run a good bead of OSI caulk as I am installing the piece of siding. Hold it firmly in place and nail. Let the caulk ooze out and don't touch it until it is dry.
When you go to paint, slice the caulk off with a razor sharp chisel and paint. It seems to work for me, although you're going to get some movement in the joint with the seasons.
I think this makes the neatest, most inconspicuous joint possible.
OSI Quad? IMHO it's awesome caulk if you don't mind the price and the fact that it's a little hard to work with... And your method is the best, assuming your the siding guy and painter, or there is a little painter in the siding guy... :-)
We used Certainteed and had to tear down an entire house of siding because they shipped a defective batch. The but joints also on the new batch had the same caulking problem where the caulking shrinks and the but joints look like they swell a small amount. We used samples of OSI caulk, we used McCormac caulk, Sherwin Williams, Dap all with the recomended ASI 920 by Certainteed and Hardi Plank. The caulk or the sididng still shrinks. Some builders are using aluminum flashing behind the but joints or 30 W tar paper with no caulk. I have taken down siding that had tar paper behind it that was 30 years old and the tar paper was still in good shape.
Hardi Plank spec calls for 2" at the roof and at any area next to concrete like a porch. I does not look too good. No builder in this area is using that spec. We are in the Washington DC area and have had no call backs for this problem in 10 plus years of using Hardi Plank and Certainteed siding. However the Hardi Plank rep stated they will not Warranty their product unless their specifications are used. JLC wrote many of the specifications that Hardi Plank is using.
So the question is if there is anyone out there whom has used flashing behind the joints without caulking for any period of time without problems?
I held the Hardie 2" on my dormers. That is really the smallest you can get a paint brush under later to paint that edge in my opinion.
The last Hardi job, second job in 15 years, we followed the spec as best as possible.
We installed for a builder, and if anything goes wrong we would have to take the blame, if we didn't follow the specs.
We installed the Hardi 2"off the roof. We sprayed any exposed step flashing black, and covered it with tyvek and roofing shingle strips. After it was all done, the two inch was hardly noticable.
As a sub, we don't have the luxury of doing things the way we would like some time. The guy paying the tab has the final say with his checkbook.
Greg in Connecticut
My company manages condos in Dayton OH. We replaced the LP siding on 208 units over the past three years using the factory finished Hardiplank. For the first half of the job we were using the color matched caulking at the butt joints. I do not know what brand, but I think it was Hardiplank's own brand. I will ask my employee who manages this community. If not,it was one they recommended because we worked closely with the company reps due to the large size of the job. They were on site many times to advise us and check the work. We started to notice that the caulking was not aging the same as the siding and was really starting to show. It looked awful. You can imagine the calls and complaints we got from the condo owners. Hardiplank then told us not to caulk the butt joints. They said to use Tyvek as flashing under the butt joints, which we did on all remaining buildings.
We dry rolled paint on the siding with the caulking (at our expense) and it has improved the appearance. The color is now uniform and if you could not see the caulking in the joints, you would not be able to tell which buildings had the problem.
I don't know whether you should caulk butt joints you will be painting, but I would never caulk the factory painted.