Polyurethane. Polyurethane caulk is considered the superior caulk to both silicone and latex because it's super durable, tear resistant, waterproof, flexible, and able to be painted or stained. Because of its superior ability to adhere to almost any type of surface, polyurethane caulk can be expensive.
Acrylic Latex Caulk *Plus Silicone - In my opinion this is the minimum standard of sealant that should be used for interior painting project applications such as the joints where baseboards, door & window casings, and crown moldings meet the walls.
Latex and silicone caulk are the most common types. The two materials are sometimes combined and sold as siliconized latex or latex plus silicone. These products offer the easy use of latex with the added durability of silicone.
Polyurethane. Poly caulks are generally tougher than other sealants, making them a good choice for driveways and other areas that take a beating.
In general, sealant is the prefered sealing solution for bathtubs and showers, as it is more water resistant than traditional caulk. Silicone sealant forms a watertight seal that is resistant to heavy temperature changes.
DAP Dynaflex 230 Premium Elastomeric Sealant
Its formula is specially designed to resist cracking and improve flexibility over other latex-based caulks. After application, it should be ready for painting in about 2 hours. During the test, we found Dynaflex 230 very easy to apply.
The Best Silicone Sealant Overall—Gorilla Clear Silicone Sealant Caulk. This Gorilla sealant is made of pure silicone and is excellent for any heavy-duty or touch-up project. The sealant is waterproof and can be used in both indoor and outdoor applications.
Sanded caulk adheres better to wet surfaces and large gaps than unsanded caulk, but unsanded caulk has a smoother appearance and texture that creates a cleaner finish than the sanded alternative.
Cement-based caulk - This type of caulk is made from cement and dries hard and inflexible. It is typically used for sealing gaps and cracks in concrete surfaces.
Caulk makes your surface airtight and watertight. Silicone sealants, on the other hand, remain flexible for years which make them ideal for areas that are prone to expansion and contraction. Silicone has strong binding properties that can be applied to almost any surface both indoors and outdoors.
Removing the old caulk and replacing it with a new bead of caulk instead usually creates a better seal. However, you can effectively caulk over caulk as long as the bottom layer of caulk isn't damaged or moldy. The old caulk should also be clean, dry, and free of oil for the best adhesion.
While caulk is long-lasting on solid, unmoving surfaces, silicone sealant's flexibility means it lasts longer in areas with higher moisture. Using silicone sealant in a bathroom for sealing cracks in the tub and shower will create a more durable seal without needing to frequently re-apply.
If you need to paint over that which you are sealing, then it is best to use acrylic caulks because paint cannot be applied over silicone. Silicone is best when sealing a window from the outside because it can resist higher moisture levels making it mildew resistant.
The key distinction between caulk and sealant? Elasticity. Caulk is typically made from a mixture of latex and acrylic materials, which make it more rigid and prone to shrinking when cured. A sealant offers superior elasticity and water resistance because it primarily contains silicone.
You can use concrete caulk on both vertical or horizontal cracks. Our top pick is Sikaflex Pro Select Self-Leveling Sealant. Self-leveling caulks flatten out as they dry, so you don't have to smooth them out yourself.
This type of caulk should be used where concrete slabs meet or where they meet with a building. A polyurethane caulk works best here, but silicone will also do.
Gorilla Clear 100% Silicone Sealant Caulk, 10 Ounce
This 100 percent silicone caulk adheres to most surfaces easily to create a mold- and mildew-resistant barrier. It remains flexible throughout its life, and it won't shrink or crack like some siliconized caulks might.
A line of caulk (called a "bead") should be no thinner than ¼." Thinner beads shrink while drying, creating too thin a seal to tool or seal properly.
In general, silicone caulk is usually ideal for waterproofing because it is 100% waterproof, however some types of specialty caulk may use waterproofing technology that is superior to that of silicone.