# Cemplank or Hardiplank installation question



## AtlanticWBConst. (May 12, 2006)

The million dollar question is: What kind of caulking did they use?

We install flashing squares behind all seams, and only use *polyurethane caulking,* specifically made for fiber-cement board siding, on all the seams and edges..


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## prstlk (May 12, 2008)

*not sure what kind but*

still wondering if the joints should be solid or apart? 

If the joints are to be solid I will make sure they use the correct type of caulk...because they will have to redo the caulking! If not then I will ask...


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## AtlanticWBConst. (May 12, 2006)

Here's the link page for Hardieplank installation instructions. All fiber-cement-board should be installed similarly:

http://www.jameshardie.com/homeowner/products_siding_hardieplankLapSiding.py?openTab=jsnavLink4


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## prstlk (May 12, 2008)

*went there*

and still had no answer to my question thus why I posted here...

it shows leaving a gap then caulking and talks about using caulk according to mfgs guidelines, and so on but...

it still does not answer the root question I have - are the joints supposed to be solid or seperated, cracked apart, not attached to the plank beside it - by the caulk?


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## AtlanticWBConst. (May 12, 2006)

prstlk said:


> it shows leaving a gap then caulking and talks about using caulk according to mfgs guidelines, and so on but...


I believe you are mistaken. It does not show leaving a gap. It shows nail placement at 3/8" from the edge/end of the board's seams. 

In fact, look at page one, diagram on the left. 
The wording says clearly: *"Install planks in moderate contact".* See what this means below.
Cemplank installation Link (Same as Hardieplank): http://www.cemplank.com/install_plank.pdf



prstlk said:


> it still does not answer the root question I have - are the joints supposed to be solid or seperated, cracked apart, not attached to the plank beside it - by the caulk?


The problem with your question, is that it did not make grammatical sense, and was thus confusing. There is no such concept as a "solid joint". A joint is a seam.
If you are trying to ask: _"Do I butt my siding plank ends tight at the seams, or do I leave a gap?"_ Then, the answer is; you butt the ends "in contact with each-other" at the seams (seam ends). The general practice is to install the siding, so as to not allow any water infiltration, so the seams are butted together without a gap. They are also caulked according to manufacturer's specs. The ends/corners, should also be caulked.
As far as caulking goes, I saw on Cemplank's installation instructions, they advise the use of a siliconized latex (paintable) caulk.

The term "Moderate Contact" is used by the manufacturer, to imply that you want the seams meeting, but you DO NOT want them so tight, that there is no room for minimal expansion. So the procedure is to install so that the ends are "touching eachother".

Reasons why caulking might crack shortly after the initial siding installation:
1.) Boards were damp, and contained moisture prior to installation, were caulked, and slightly contracted pulling caulking apart.
2.) Wrong kind of caulking used.
3.) Caulking applied at improper temperature, or weather conditions.
4.) Board ends were not securely fastened, boards had conditional movement, and caulking seperated.
5.) etc (other reasons not listed)....


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## prstlk (May 12, 2008)

*Sorry for confusion but*

:huh:I'm not a builder here...I'm just a homeowner trying to find out if we need to have the siding company come out and do something to the joints between the planks of the siding. We have a final walk through scheduled for Tuesday and this is one issue I want to know something about so they don't just tell me that is the way it is supposed to be.

They were originally caulked and now the caulk beads have all cracked apart. I have no idea why this has happened. It is my gut feeling that they should not be this way but I wanted to check before our walk-through.

After the mistake was made by the builder and the wrong siding was put on in the first place I question whether it is installed correctly.:confused1:


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## Bud Cline (Mar 12, 2006)

Those cement siding products come to the job naturally dusty. Caulking over dust wouldn't be a good thing. I'm wondering if siding applicators even address this issue when installing siding.

I would also check to see what caulk is recommended by the manufacturer and what caulk was used on the job. It isn't unusual for a manufacturer to specify a quality caulk to be used with their product and have the builder/installer buy the cheapest product available as a substitute. If this is the case, where you quoted for the higher priced caulk?

I would also be curious to know the variance in cost of the two siding products. Hardie is a quality product with a good reputation, I wonder if this is the case with the product that was substituted. Do you have a credit coming because the product used cost less than the product specified?

just some questions that come to mind.


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## buletbob (May 9, 2008)

Explain to the contractor that the caulking all cracked. if he gives you a story hold back the final payment until the problem is corrected. 
If they are a reputable company they will agree and fix the problem. 
You stated they all ready supplied the wrong manufacture, this should of been discussed with you pryer to the install.


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## molarsmile (Jun 9, 2008)

*cemplank/hardiplank*

Does anyone know the exact difference between the 2 kinds of sidings?
Our builder initially promised for hardiplank for our newly constructed house with a 50 yr warranty but what we are getting is Cemplank with 25 yr of warranty! Looks like we are in the same boat as Prstlk! 
Our closing is soon....this week itself...Any advice will be appreciated!
Thanks




prstlk said:


> On a new house we are having built the builder has installed Cemplank siding (it was supposed to be Hardiplank but that is another thread issue).
> 
> Everything looks good except the joints of the product. They have caulked but many - actually most - of the joints have "broken" or cracked apart - meaning the caulk has not held - it has come apart.
> 
> ...


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## AtlanticWBConst. (May 12, 2006)

molarsmile said:


> Does anyone know the exact difference between the 2 kinds of sidings?
> Our builder initially promised for hardiplank for our newly constructed house with a 50 yr warranty but what we are getting is Cemplank with 25 yr of warranty! Looks like we are in the same boat as Prstlk!
> Our closing is soon....this week itself...Any advice will be appreciated!
> Thanks


From what I understand, they are one in the same.

JamesHardie has owned Cemplank since 2001: http://www.cemplank.com/new-011212.shtml

Cemplank is run as a separate division of James Hardie (a James Hardie subsidiary).


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## prstlk (May 12, 2008)

*Hardi vs Cem*

When we were first told about the "accidental" placement of the wrong stuff on the house they offered a $400 credit towards our closing costs for the mistake. Thinking this was not enough I called around to 3 different builders supply companies in our area and found that this was the approximate difference in the cost between the 2 products. We agreed to the credit. Like stated by AtlanticWBConstr it seems that Hardi Products bought Cem Products about 5 years ago and they are all made by Hardi Products now. 

I would love to know where molarsmile is located as well!

I still am not clear on the caulking and joint issue so I will try to find a telephone number to call today about it.


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## Termite (Apr 13, 2008)

prstlk said:


> I still am not clear on the caulking and joint issue so I will try to find a telephone number to call today about it.


I read every post on this thread and I still don't think I understand the description of the problem. 

You say the joints have broken or cracked apart. Do you mean that they have separated and the caulk didn't bridge the gap? The caulk has somehow released or cracked?

Or, did the siding material itself somehow fail, crumble, or crack at the joint location? This would certainly cause the caulk to have problems. 

Fiber cement siding is very dimensionally stable, and in most cases it shouldn't shrink after installation. Being cement-based, it can expand and contract, but I doubt that it would do that to the extent that the joints would separate. Structural issues with the home such as settlement would certainly cause joints to separate.


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## prstlk (May 12, 2008)

*Yes yes yes finally someone understands!*

*You say the joints have broken or cracked apart. Do you mean that they have separated and the caulk didn't bridge the gap? The caulk has somehow released or cracked?
*
Yes - this is exactly what I mean...


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## AtlanticWBConst. (May 12, 2006)

I would still advise using a paintable polyurethane caulk on fiber-cement siding.


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## Termite (Apr 13, 2008)

Ok, easy enough. Follow AtlanticWBConst's advice on caulk for sure. 

Before recaulking, you'll/they'll need to remove the existing caulk from the joints with a knife or putty knife. That way you're not caulking over caulk.


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## virtualfriday (Jun 16, 2008)

Concrete shrinks period........... I have used numerous brands of cement siding and about every type of caulk and they all crack at the joints eventualy. Even if you can find a caulk that will bridge the gap between the largest spaces your house paint is bound to fail at the joints as it can not handle the movement like a good flexible caulk can. I suppose you could find a caulk that matches your house color so when the paint fails over the caulk it shows the same color but I would not bother.


My solution is to use splices but make sure and put them in tight as I have seen a house where the cement siding shrunk so much all the splices fell out of the South facing side.


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## AtlanticWBConst. (May 12, 2006)

virtualfriday said:


> Concrete shrinks period........... I have used numerous brands of cement siding and about every type of caulk and they all crack at the joints eventualy. Even if you can find a caulk that will bridge the gap between the largest spaces your house paint is bound to fail at the joints as it can not handle the movement like a good flexible caulk can...


Do some more research on Polyurethane, or Urethane caulk.


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## virtualfriday (Jun 16, 2008)

AtlanticWBConst. said:


> Do some more research on Polyurethane, or Urethane caulk.


No reasearch needed, plenty of caulk out there to handle the larger movement without failure. I have used Sonneborn NP1 with great results on various projects. Now just show me a regular house paint that can be applied to NP1 and handle the the movement without failure?


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## rarnold441 (Jul 13, 2008)

*Butt Joints will crack*

I have HardiPlank siding on my home. It is 6 years old. The joints between planks on my house also cracked within a few months or a year. I dutifully picked all the caulk out and resealed them. However, they soon cracked again. After discussing with the manufacturer I found the recommendation to be "To follow the caulk manufacturer's installation guidelines". Meaning that the caulk typically will not adhere well in a butt joint, and the caulk certainly needs a minimum gap to be effective. A very narrow joint of 1/8" or less is too small to get an adequate bead of caulk in. The better method is to use some type of flashing behind the joints to help shed the water. My house had several problems with flashing, house wrap, design, drip guards, etc., so that now I am faced with tearing the back side of my house off to fix all the rot.


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## AtlanticWBConst. (May 12, 2006)

rarnold441 said:


> ... The better method is to use some type of flashing behind the joints to help shed the water. My house had several problems with flashing, house wrap, design, drip guards, etc., so that now I am faced with tearing the back side of my house off to fix all the rot.


:thumbsup: I've been saying this all along....


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## skn (Aug 3, 2008)

*Cemplank vs Hardiplank*

I am currently getting bid for a siding job. The contractor at my house right now just offered cemplank as an alternative to hardiplank. He states the product is exactly the same...the only difference is that it is cheaper because you agree to a 25 year warrenty instead of the 50 year warranty that comes with "hardiplank"

He roughly put in the numbers for my house and the savings would be approximately $2,000.00. With this info I'm concerned the that the $400.00 offered in reagard to the mistake (contractor putting Cemplank on instead or hjardiplank) is not a fair compensation. I guess it would depend on the size of the house and number of planks...

I would ask for a larger discount..or call another contractor with the number of cemplank boards used on your house and ask what the price differnce would be.

As far as the caulking...it does not sound right...if it was nice and seamless at the completion and now is gapping or separating they need to re-do it. It could be weather dependent and not a true reflection of the quality of job they did, but they should fix it before you pay the final payment. And if it happens again in 2 weeks they should fix it again. 

My 2 cents :0)


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