Hardie Panel Question

[bmsemple1]

We recently installed hardie panel (smooth) on the exterior of our home. They are 4x8 panels that were installed side by side with small gap for expansion. We are trying to achieve a flat wall appearance with no gap. We have caulked it but it shrinks and you still see the gap. We have tried bondo which cracks with movement or peels off. We have tried spackling compound from Sherwin Williams. I was wondering if anyone knows of any products that would help us achieve the desired look. We just dont want to paint it and have it cracking and peeling. Thanks for all your advice or help.

 

[sselander]

I have HardiPlank on my home.
Have you looked at the website James Hardie has for installation help/info yet?
http://www.hardieinstallation.com/

 

[upndown]

If all else fails, you could always put on Bat strips. Give it more of a rustic look that would hide those gaps.

 

[altersaddle]

My workshop got hardie plank installed. I used flexible acrylic sealant on the joints. It's very stretchy and can be painted.

Hasn't cracked or fallen out yet, and it has been on for about a year.

The bondo and spackle likely don't have enough stretch to handle the expansion / contraction of the planks.

I think this is what I used:

http://www.homedepot.ca/product/300ml-white-alex-plus-acrylic-latex-caulk-with-silicone-35-yr/941847

 

[Jackfre]

I am installing the same panels in the gable ends on my new garage. We are doing vertical 1x3 Hardi batts 16" oc. Without the bats the panels get wavy. All you can do is wave back.

 

[Hpozzuoli]

If all else fails, you could always put on Bat strips. Give it more of a rustic look that would hide those gaps.

Easiest solution and adds some character

 

[ThePress]

We use Dymonic caulking, which is a flexible caulking often used in expansion joints on brick walls, etc...

 

[bdamico]

elastomeric caulk. i like lexel

 

[BillK]

b,
No matter what anyone says, I don't believe you will be able to get the effect you want, meaning a perfectly smooth wall with no visible joints. Only way that will happen will be if you can get a sheet of Hardi to cover the entire area with no joints.
Any material like that is going to expand and contract with temperature changes. There is simply no avoiding it.

 

[dfiler2]

Here's what the manufacturer says to use.

CAULKING
For best results use an Elastomeric Joint Sealant complying with ASTM C920 Grade NS, Class 25 or higher or a Latex Joint Sealant complying with ASTM C834.
Caulking/Sealant must be applied in accordance with the caulking/sealant manufacturer’s written instructions. Note: OSI Quad as well as some other caulking
manufacturers do not allow tooling.

 

[BillK]

Here's what the manufacturer says to use.

CAULKING
For best results ..................

But that is still not going to give him the perfectly smooth, joint free finish he is looking for.

 

[RivennHewn]

Last job I did with hard panel I used galvanized sheet metal behind the joints, and left the 1/8" joint open.

Once painted nobody ever had a problem with it.

I used 5" wide metal, and used Sikaflex behind the panel edge in about an inch so it wouldn't squeeze out into the joint.

 

[slip knot]

I used a H track to seal the joints in my wifes greenhouse and it looks ok painted. On the Hardie plank I've used the tin flashing and Sikaflex both with good results. The OP wants a smooth finish but I dont think either type of joint prep will be very noticable. As long as the joint doesn't crack it wont be very noticable.

 

[txvwnut]

Maybe try the mesh tape (used for drywall tape and bed) then use mortar like you would for stucco and finish it like its a Sheetrock type wall. Feather out the joints the best you can then paint.

 

[RivennHewn]

I have Hardi on my house, and one thing I will say is that it does move.

I was surprised at just how much some of the gaps change seasonally.

Anything that doesn't move with it will fail.

 

[Justanoldguy]

b,
No matter what anyone says, I don't believe you will be able to get the effect you want, meaning a perfectly smooth wall with no visible joints. Only way that will happen will be if you can get a sheet of Hardi to cover the entire area with no joints.
Any material like that is going to expand and contract with temperature changes. There is simply no avoiding it.

Ditto

 

[egdede]

Here's what the manufacturer says to use.

CAULKING
For best results use an Elastomeric Joint Sealant complying with ASTM C920 Grade NS, Class 25 or higher or a Latex Joint Sealant complying with ASTM C834.
Caulking/Sealant must be applied in accordance with the caulking/sealant manufacturer’s written instructions. Note: OSI Quad as well as some other caulking manufacturers do not allow tooling.

That is a smart answer. Cosmetically speaking, a latex based mortar, concrete or stucco caulk could be tooled to match the hardie panel (depending on the exact texture). I would try the latex mortar repair product first. So, do products like this meet the above specs?:

http://www.zoro.com/i/G4625652/?utm...gclid=CP2lxfy4kMUCFRcvgQodo7MAqg&gclsrc=aw.ds

 

[Norcal]

If no seams is desired then stucco would be the only choice, there is no way to conceal the seams in sheet goods, as others have suggested batts are a good way to cover the seams, board & batt siding is what is on my shop it has done pretty good since 1994 & it's plain rough sawn fir siding w/ cedar batts, the Hardi product should be even better.