I often tell my clients to use elastomeric caulking when they do their projects around the home.
Elastomeric caulking is very often found in the tubes that say 25, 30 and 40 year warranties.
A couple of definitions:
Elastomer - this is an elastic polymer. As a caulking formula it retains a lot of viscoelasticity.
Viscosity is when a material resists strain when stress is applied - like honey.
Elastic materials strain when they are stressed, but return to their original state - like a rubber band.
This combination would made an ideal caulking! You are looking at chemistry at work.
When it dries it is very strong, but retains its sponginess. It is exceptionally long lasting.
Elastomeric caulking can expand as much as 200%, but once smoothed it will not lose its edge. The expansion happens inwardly and fills spaces extremely well.
It dries quickly and provides excellent waterproofing qualities.
Elastomeric caulks have these characteristics:
--> The ability to bond with many things - metals, concrete, glass, plastic and wood.
--> It retains its characteristics in hot and cold climates.
--> Once dried it resists expansion or shrinkage, no matter the dryness, humidity, weather or temperature outside.
--> Indoors it will work with wood baseboards and trim, plastic and porcelain bathroom materials, ceramic tile, fireplaces, and drywall.
--> Outdoors it works with all kinds of trim, flashing, gutters or downspouts, and concrete.
As with all caulking, the surface must be clean and dry. That gives maximum adhesion. Once applied and painted it will last a long time.
When looking to buy elastomeric caulking, be sure to buy only the premium labels. Some formulas might say "elastomeric" in the list of materials, but those are hybrid caulks, or blends.
GET THE GOOD STUFF! ALWAYS GET THE GOOD STUFF!
My recommendation: when you do projects, do them right! Use the right stuff. Get the best information. And do things that will last a long time. Home maintenance is just that. It should not be a career where the same thing is done over and over again soon after it was done the first time. THAT is a Best Practice!
Jay Markanich Real Estate Inspections, LLC 
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560
Oh yes, that is good stuff. Very important to have something that withstand temperature fluctuations.
Well again I learned something today in the Rain. thanks for posting
Is very good stuff is Debbie. I recommend it to my clients all the time.
James - I post things like this from time to time because what may seem old hat to me is often new information to many people.
Jay, I always seem to purchase the wrong caulk. Thanks for setting me on the right path.
Good morning Jay,
I will have to check what I am using as it is time for preventative maintenance!
Make yourself a great day.
Jay, That is good stuff! It is important to use good caulking, it saves in the long run! Have a great day!
Jay- inasmuch as I've never in my life purchased caulking, I'm passing this post on to my husband.
Tom - a little information can go a long way, and be a little dangerous!
Raymond - it may always be time for preventative maintenance!
T&D - use what's good and what lasts.
Kathy - you little chauvanist! Your husband? Man's work? Sheesh.