Does Hardiplank Require caulk at the joints?

[Joe Funderburk, CMI]

I've always seen the joints caulked....until this past Saturday. A 3000 SF house had not one speck of caulk at the end joints (it was caulked at the trim).

The instruction state: "James Hardie does not recommend the use of caulk at field butt joints."

[Randy L. Mayo, PE]

Joe

I had the same situation a few weeks ago and the hardiplank site said DO NOT caulk butt joint. Here is the link:
http://www.jameshardie.com/builder/p...Tab=jsnavLink4

[Joe Funderburk, CMI]

Note the photo of a special flashing required behind the butt joints. Not sure how the code inspector, or I, could verify the flashing.

[Nick Gromicko]

Caulking is one of 4 ways James Hardie recommends handling vertical butt joints of non-colored 4' X 8' sheets.

[Joe Funderburk, CMI]

Originally Posted by gromicko

Caulking is one of 4 ways James Hardie recommends handling vertical butt joints of non-colored 4' X 8' sheets.

4x8 sheet? I'm speaking about traditional lap board.

[Stephen W. Stanczyk]

They have changed their installation requirements over the years. Used to be standard to caulk, now they say no. I always caulk field cuts but if there is a good installer, those cuts will be next to a trim board that will be caulked anyway. I use 30# felt in back of the joints. If you run a thicker sewing pin down between the two pieces, you can feel if the flashing is there.

[Nick Gromicko]

Joe, I think your image is specifically for ColorPlus where they don't recommend caulking.

For regular Hardiplank lap siding (the kind you paint AFTER installation), caulking at butt joints is optional. This from installation instructions:

A high quality, paintable caulk is recommended. For best results use caulks that comply with either ASTM C 834 or ASTM C 920. Caulking should be applied in accordance with caulking manufacturers written instructions. (Leave 1/8” gap at trim for caulk. Caulking at butt joints is optional.)

[Nick Gromicko]

As a side note, it's been my experience that it isn't worth paying for the ColorPlus stuff because it gets all scratched up during installation and you'll have to re-paint it anyway.

[John E. Mullarkey]

Having done many of these instalations, I could not agree more. Even the cuts make the job look poor. Good advice Nick.

[Joshua L. Frederick]

http://www.youtube.com/watch?v=9Vy1l79CO1E

[Michael Roberson]

As a side note, it's been my experience that it isn't worth paying for the ColorPlus stuff because it gets all scratched up during installation and you'll have to re-paint it anyway.

I will second that Nick, Having installed it. It does allow you to one coat finish though.

[Roy D. Cooke, Sr]

Thanks Joshua Good explanation... Roy

[ROBERT V. YOUNG]

Yes Josh.
Flashing is the weakest link in all the building trades. From electrical to hardboard installers, slate repair roofer to patio and deck installer at the sill plates.
The old-school hard nosed teachers are fewer and farther between.