Acrylic latex caulks, for example, are the most popular. They adapt well to drying green wood on a job site and adhere to many different substrates. They are paintable, low in toxins, easier to “gun” than polyurethanes or rubbers, and can be cleaned up with water.
Synthetic rubber. Synthetic rubber is a relatively new caulk category. It is perhaps the most flexible product on the market. Synthetic rubber cures clear and is ideal for exterior joints that typically expand and contract.
Exterior silicone caulk is the most common type of exterior caulk because of its incredible durability and water resistance. Silicone is also a very flexible material, even after it cures, making it an ideal option for sealing drafty windows and doors.
Placing caulk over large portions of wood siding prohibits the natural movement of the wooden panels and can cause extensive damage to the exterior of your home. Many professionals, like those at James Hardie, also agree that you should not use caulk on fiber cement siding unless there is no metal flashing underneath.
What caulk is good to use for the house exterior? Several types of caulks are used for sealing home exteriors like siding, gutters, roofing, and masonry. Silicone caulk or a silicone-latex hybrid is excellent for exterior windows, doors, trim, and siding. Butyl rubber is best for outdoor use such as around gutters.
Sometimes known as acrylic latex caulk, this type is best for use with drywall, wood and masonry. It's often called "painter's caulk." This caulk is inexpensive, easy to use, seals well without odors and cleans up easily with water.
However, it is important to be aware that silicone caulk is almost never the right choice for wood. If you are looking to seal wooden joints such as those around many types of windows, here are the problems you will face if you opt to use silicone caulk instead of other options like vinyl latex caulk.
Flex Seal is a liquid rubber sealant coating that's perfect for almost any DIY project inside or outside your house.
Wood: For sealing gaps in wood, a silicone caulk such as DAP 100% Silicone Window, Door and Siding Sealant is a great choice. It's waterproof and can withstand extreme temperatures, making it ideal for use around windows, doors, and siding.
Holes in wood trim are best filled with wood filler. Nail holes in exterior surfaces, just as with cracks or gaps, can be dealt with using a good caulking. Take the time before you apply any paint on your next project to fill all of the gaps, cracks, and nail holes.
Wood doesn't always sit flush when installed, and it will wear out over time, causing cracks and gaps. In most cases, the solution to fixing these gaps is using a wood caulk to create seamless, safe, and secure structures.
There are no guarantees with silicone - it is almost impossible to remove. If the silicone has migrated into the wood through cracks in the old finish, you may not be able to get it all removed.
Firstly you need to understand that silicone does not stick to anything other than the adhesive system or the PSA (pressure sensitive adhesive). This means silicone does not interface directly with wood or metal or any other material, instead it interfaces with the PSA itself. The diagram below explains this.
There are two main places it never should be installed, wood or any painted surface. If paint will ever be applied to an area, then silicone does not belong there, ever, in any way. If you have a wood element (painted or not) in your house silicone should never be applied there either.
* If cost isn't a consideration, the new tri-polymer or copolymer caulks are the best choices for versatility (about $4 to $6). Proflex by Geocel and Lexel by Sasho are multi-task sealants designed to adhere to dissimilar surfaces such as metals, glass and untreated and treated wood.
Perhaps the most common type of caulk you will encounter is latex caulk, sometimes called acrylic latex. It adheres well to wood, stone and drywall, which makes it ideal for interior uses.
The polyurethane caulk can be used on plastic, concrete, wood, metal, and glass. It also adheres very well to vinyl siding, aluminum siding and brick. The only thing you should be careful with is polycarbonate plastic.
The life span of the exterior silicone sealant.
Its optimal lifespan is around 10 years, but an annual or bi-annual inspection is essential to avoid too much deterioration. The exterior caulk of a home must resist the elements.
Using silicone as a sealant will provide objects with more flexibility; the ability to expand and contract freely. When Caulk dries it becomes more rigid, making it ideal for projects that require the least expansion and contraction possible.
How long does silicone waterproofing last? Silicone sealants can stay waterproof for around 20 years, but this varies according to different factors including temperature, UV exposure and the chemical properties of the sealed materials.