Note there are constantly new caulking products that mix recipes or overlap usages. Their drying times, health hazard/risk, traits and usage significantly change by caulking type.
Silicone, Acrylic, Butyl, Polyurethane & 2-Part Epoxy are all kinds I'm familiar with.
This article is about Silicone & Acrylic caulking (see below).
To decide which you need to use, there is one critical piece of information you need to understand: usage.
Caulking purposes in residential:
- Waterproofing, (Most Common)
- Gap filling (Most Common)
- Vapor Sealing
- Soundproofing (not going to cover that in this article)
- Fire Rating (not going to cover that in this article)
ACRYLIC / LATEX CAULKINGS
- Are used primarily in "finishing" environments,
- Are "waterproof" but not recommended for the primary waterproofing,
- Are paintable (hence "finishing") but comes in a variety of colors,
- Great at Gap Filling,
- Easy to clean up with water,
- Comes in a variety of colors.
100% SILICONE CAULKING
- Is typically NOT paint-able BUT you can buy expensive ones that are,
- Typically Clear, Translucent or Transparent but you can get them is different colors as well,
- Is sometimes great as an adhesive for things like back splashes, counter top anchoring, mirror anchoring, and other smooth surface to smooth surface "blob" gluing,
- Highly flexible,
- Resistant to shrink/expansion,
- Doesn't want to dry out or crack.
- Smells powerful and is hard to clean up.
- Used as the primary waterproofing caulking.
- Resistant to mold.
- Reacts with neoprene washers (turns yellowish).
- Can get Fire Rated Silicone based caulking.
Here are some quick test questions to help you understand the differences.
USAGE TESTING QUESTIONS
1. Question: What kind of caulking would I use around a tub surround?
Answer: 100% Silicone
2. Question: What kind of caulking would I use with a window installation?
Answer: Behind flanges for example, use silicone. Behind any trim use either silicone or acrylic. Visible sections around trim or flashings, use acrylic.
3. Question: What kind of caulking should I use around a sink?
Answer: Use Silicone.
4. Question: What kind of caulking would I use on a metal roof?
Answer: Drying times, UV(Ultra-Violet) ratings & specific usages make a difference here. Typically Silicone is handy, especially with flashings however, a Butyl caulkings is sometimes better. For shingles, a Polyurethane caulking is more preferred. However, there are cases where either can be used however, pay attention to UV rated products, drying times and what you're adhering to. Epoxy caulkings are also an option however, they are way more toxic, cost more and are good for mortar/concrete solutions.
A lot of the time you just need to know about Silicone and Acrylic because it's the most common for homeowners.
You can read the backs of the tubes for the more specialized, usage specific types.
Don't use acoustical sealant (because it's black and water resistant) on a roof! That's for sound & vapor barrier penetrations!
Cheers!
