I need a recommendation for exterior caulk for hardi siding. I am about to repaint my entire house and I am spending the next few weekends preparing. My father recommended ALEX +, though searching around online people are saying Shermax from Sherwin Williams, Big Stretch from Sashco, and one from Benjamin Moore.

What is currently some of the best caulk out there?

I've been using Big Stretch since 2004. Great product and I won't use anything else if I am do paintwork

Big Stretch comes in an elastomeric and a latex based form. elastomeric is much better...

We recently repainted house and I used the sherwin Williams stuff. Bought a case of it to make sure I had enough. Still have 3-4 tubes that have come in handy around the house since.

I would 2nd & 3rd Big Stretch- I've used a bunch of it. However, it's expensive. If you use it, buy it online rather than local retail. You can save quite a bit. Pay attention to paint & cure times- they're longer than other caulks. Big Stretch and Lexcel seem to be benchmark products but they come with a price attached.

There is a good alternative that I have used in covered patios and screen porches and have had equally good results. DAP Alex Flex which seems to be targeted to the same applications as Big Stretch and is half the Big Stretch price. I've used it quite a bit and it performs well. Lowes has put it on sale a couple of times 2 for 1.

Look at BASF np1. It is a non sag elastomeric joint sealant. It's great sealant, but don't get it anywhere you don't want it.

As far as expensive, prep is 90% of a successful paint job and caulking cost is a small fraction of material cost. The most I have used on 1 job is 20 tubes and it was new construction. So using $2 cheap caulk only would have saved $87 on the total job and it's simply not worth the headache of having to recaulk and touch up for that little of money. If you buy 12 or more tubes at Lowes you can get a volume discount on it.

AgEngineer72 said:

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I would 2nd & 3rd Big Stretch- I've used a bunch of it. However, it's expensive. If you use it, buy it online rather than local retail. You can save quite a bit. Pay attention to paint & cure times- they're longer than other caulks. Big Stretch and Lexcel seem to be benchmark products but they come with a price attached.

There is a good alternative that I have used in covered patios and screen porches and have had equally good results. DAP Alex Flex which seems to be targeted to the same applications as Big Stretch and is half the Big Stretch price. I've used it quite a bit and it performs well. Lowes has put it on sale a couple of times 2 for 1.

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How does the Alex flex hold up long term on exterior applications ?

The 30 minute before painting is appealing for same day prep and paint applications