Alex Plus White Acrylic Latex Caulk Plus Silicone
The all purpose caulk is effective for hairline stucco cracks and to seal gaps around doors and windows, baseboards, trims and moldings. It is not recommended to water submersion applications, but it is waterproof and has a durability of forty years.
If you need to seal junctions between walls and seal cracks in ceilings or walls then it's better to use Caulk because it dries quicker and is much more resistant to weathering and high temperatures.
caulk is good for cracks applied with a scraper. try to get it flat first time as you cannot sand it. if it is a really fine hairline crack like the type you can get in new plaster then a good emulsion will cover it. if it is worse a drastic solution is to have the walls reskimmed using scrim over the cracks.
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.
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.
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.
Crack sealing is a more costly procedure for the pavement owner but provides substantial value due to its long life expectancy. While crack filling may only last one or two seasons depending on the cracks activity, crack sealing can last up to 8 years or more and is considered a permanent treatment.
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.
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.
“Sealant” is the general and correct term for the chemical used to seal. “Silicone” is one type of sealant. There are also acrylic sealants, polyurethane sealants etc. Silicone sealants are the most prevalent type of sealant.
SILICONE SEALANT LIMITATION
Possibility of surface dirt retention due to static charge. Not successfully paintable (in general for high quality silicones) Primers may be required on some surfaces. Lower tear and abrasion resistance.
A silicone sealant can last anywhere from 10 to 20 years, depending on the quality chosen and the location of the caulking in relation to the elements, such as the sun and high winds. Silicone caulking offers the best resistance to UV rays.
When this happens, the sealant “skins” over and can feel almost dry to the touch. Curing refers to the slower chemical reactions that take place under the surface once the sealant is exposed to oxygen. It usually takes anywhere between 1 to 5 days for sealant to be fully cured.
Simply use some filler to cover the crack, wait for it to dry, sand it and then paint. If it's a more severe crack and you're worried about potential structural damage, you should consult a professional structural engineer immediately.
Joe Truini: When using caulk to seal cracks and holes around the house or outside, it's important to make sure the crack is no wider than a quarter of an inch, because if you just put in caulk, the caulk will fail, because the crack is too wide.
Depending on your product label, the most common places to use expanding foam is the attic, crawl space, basement, joints, cracks, crevices, around window and door frames, and wall spaces. However, window and door frames do not need an expanding foam that expands aggressively.