# What is the best caulk to use for exterior wood or Hardie Board?



## RickMerlander (Dec 26, 2011)

Anybody got an opinion on the best caulk to use for exterior wood or Hardie Board? Ive tried using both latex caulk and polyurethane. The polyurethane lasted longer but seems to attract all sorts of dirt, even when it is top coated, and sometimes shows through the top coat when the topcoat starts to wear. Most of the joints are pretty narrow, but sometimes Im caulking gaps up to 3/8 wide. What tools well and also holds up well? Thanks.


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## joecaption (Dec 29, 2011)

I use Alex 230 on Hardee plank and never had a problum with it.
Apply it, wipe with a finger then wipe it down with a damp sponge.


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## Jdmrenovations (Jan 3, 2012)

Now that OSI Quad can be used with mineral spirits, it's my favorite.  Not easy to work with, though...takes some practice and a paint thinner soaked rag.


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