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.
Silicone is very flexible and acts as a water and moisture repellant, making it among the best caulks for both windows and bathrooms. Pure silicone is more expensive than latex caulk, but it is highly durable. Silicone caulk stands up to extremes in temperature changes and can last up to 20 years when properly applied.
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.
We recommend Loctite Painters Caulk for in-home applications. This versatile paintable caulk withstands minimal joint movement, making it friendly with countertops and other trim. From paintable silicone caulk to paintable exterior caulk, different types of painter's caulk have different functions.
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.
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.
Unlike typical decorators' caulks, the Dunlop Flexible Acrylic Filler can be overpainted with any oil or water-based paints without the need to spot prime and the painted surface will not craze or crack and remain smooth even after painting.
For a tough, watertight, mildew-resistant seal, we recommend using Loctite 100% Silicone.
Caulk Bead Cracking
The movement and/or change in joint size is a result of moisture reduction and shrinking of the wood fibers and, most commonly, it results in hairline cracks in caulk beads and painted joints, as well as separation in the panels of doors.
Never caulk over damaged or moldy caulk.
Damaged, cracked, and worn caulk won't provide a firm surface for the top layer of caulk, often leading to cracks and damage in new caulk. Remove the old layer before properly sealing the gap.
Wet Areas – most caulking is not recommended for surfaces exposed to moisture. Instead, you'll need bathroom caulk that is silicone-based as it resists water after it's sealed. Painter's caulk is for indoor dry surfaces that can be painted over. Exterior Surfaces – painter's caulk is for interior use.
1. Acrylic Latex. Acrylic-latex caulk, also known as latex or general-purpose caulk, is water-based and provides excellent adhesion to most common building materials, including wood.
What kind of caulk do you use in the bathroom? The best caulks for tubs, sinks, or shower stalls come in tubes labeled “Tub and Tile” or “Kitchen and Bath.” These are either acrylic latex or silicone compounds that have been chemically tweaked to resist mildew and to stick to smooth, nonporous surfaces.
Caulk: Generally made of flexible acrylic, mastic caulk has a smooth plastic type texture. Best used for filling gaps between skirting boards, doorframes or the edges of shelves and the wall.
Gaps up to 1/4″ inch in size can be caulked in the usual manner, without any concerns. If the gap is larger than a 1/4″, you will want to install a foam backer rod into the joint, prior to caulking.
Deep or wide crevices should be lined with foam backer rod first. Use a putty knife to force the flexible backer into the crack until it sits at least 1/4 inch below the surface. Then fill with caulk.
Smooth the Caulk Bead
Whichever method you use, the overall goal is to smooth the bead and not to remove excess caulk. For best results as you figure out how to use caulking tools: Lightly drag the caulk finishing tool over the bead to smooth it. Alternatively, you can use your finger.
Caulking Tips
An index finger works fine when tooling a bead of water-based caulk. An ice cube is another alternative. It's best to tool silicone and polyurethane joints with a plastic spoon or a caulk tool. For poly caulk, wet the tool surface with solvent to get smooth results with this super-sticky material.
Certain places on the exterior of the home should not be caulked, since they'll cut off openings needed for air circulation or drainage. Elegant Painting says these spaces include the gap created when trim boards sit atop the siding, any wood to metal joints, weep holes on windows, and garage door panels.
Silicone caulk is excellent at water sealing and flexibility so it has its place in construction. There are two main places it never should be installed, wood or any painted surface.
Sealing joints on a damp surface should be strongly avoided, since silicone sealants generally do not adhere as well to moist substrates. If you want durable joints, never apply sealant in rain, freezing rain, snow or heavy fog.