We are in the process of replacing some wood trim on the exterior of our house. The house has lap side hardi plank and we are going to an Smart Panel type trim. So, some caulking will be in order. I've heard that Big Stretch, Tower Tech and Quad OSI are good caulks. On our site we get plenty of sun and heat and then rain in the winter. Based on your experience, what's your take on the best caulk?

Thanks

Don't buy HD Dap Alex Plus. It's crap.

If I paint again I'll go to Sherwin Williams, spend the extra $$$, and buy what they have. I have no experience with SW caulk but it's bound to be better than the crap HD sells.

Where exactly are you putting the caulk?
Windows? Doors?

Quad is an exceptionally good urethane caulk and comes in a very wide range of colors. It isn't as easy to use for a beginner as the less expensive latex caulk but it will do the task if it is applied correctly. Check the tubes for softness so you don't get stuck with old or frozen caulk.-Mike

IronBender:

I will be putting the caulk between the new wood trim and the existing hardi plank lap siding.

If not visible, the best is 3M 5200 marine sealant.

It's not paintable/stainable and is slow to cure, but sticks and seals like no other.

Are you applying the trim on top of the lapped siding with out scribing and coping (notching) to fit tight, and then just filling the gap that remains with caulk? How thick is the siding, and how much exposed to the weather of each siding board? If just applying the trim over the siding and filling with caulk it sounds like a "Bubba Job".

My builders used a paintable 3M caulk to seal between the trim and hardi board 9 years of Nebr heat and cold and haven't had to do any touch up repairs yet.

Kojak:

We are removing the existing painted spruce trim and then will install painted 1" thick smart panel trim. The trim will attach to the plywood subsiding on the house and the existing hardi plank lap siding will butt up against it. The caulk will be used to fill any gaps between the windows and the trim and between the trim and the lap siding. The 4" face of the trim will be exposed to the weather as will a small portion of the edge of the trim where it butts up against the lap side.

Big stretch is good stuff.

I've been out of the loop the last ten years but unless things have changed since I retired the paintable latex caulk recommended above is what I'd use.

FWIW,,,, James Hardie agrees.
http://www.jameshardie.com/homeowner/improveYourHome_resideYourHome_tipsArticles_caulking.shtml

One word of advice,,, when working with cement siding, don't wipe the excess caulk with your finger like you normally would or you'll leave a shiny spot after paint no matter how well you think you wiped it off. Let it dry and then cut the excess off with a utility knife. Time consuming but you'll end up with a better looking job.

Luck