Ask the Pro: Caulks & Sealants 101

September 20, 2021

We talk a lot about primer here on The Perfect Finish, but today we’re excited to dive into a different home renovation product – caulks & sealants! KILZ recently launched a line of caulks & sealants, created for a variety of interior and exterior projects. To share more about these new products and offer tips and best practices for using caulks and sealants in a variety of DIY projects, we tapped Chuck Eisenhauer.

A Product Manager on the KILZ team for over three years with a background in Chemical Engineering, Chuck is an expert on all things caulks and sealants. Whether you’re trying to figure out which KILZ product is right for you, or where and how to use them once you’ve bought them – Chuck’s got your answer!

Let’s start with the basics, what is caulk?

“Caulk” or (less frequently) “caulking” is a material used to seal joints or seams against leakage in various structures and piping. The oldest form of caulk consisted of fibrous materials driven into the wedge-shaped seams between boards on wooden boats or ships.

What is the difference between caulks and sealants?

Most often these two terms are used interchangeably, and the two products serve the same purpose: to fill gaps between materials and to keep water and air EITHER in or out. For us, the main difference between a caulk and a sealant is elasticity. Caulks are fairly rigid when dry and are intended for use in areas with minimal expansion and contraction. Sealants are made from flexible material making them ideal for areas prone to more significant expansion and contraction.

What types of projects typically require a caulking or sealing product?

Any project you need to seal a joint or seam! Typically, you will see caulks or sealants most often used in projects where someone is needing to replace old caulking or is sealing new joints/cracks/etc. before priming and painting. Most of our products are best used for sealing cracks, filling openings like nail holes, or sealing connection joints between stairs, walls, skirting boards, ceilings, windowsills, etc. Customers should refer to the back of the product label or the product Technical Data Sheet for information on what surfaces and situations our products can/cannot be used for.

Are caulks and sealants products always white, or do they come in other colors?

Colors will vary from product to product, and brand to brand. Here at KILZ, we have two products that have multiple colors: our Waterproof Sealant and our Premium Seal. Our Waterproof Sealant, an interior 100% silicone, is available in both clear and white – perfect for use in kitchens or bathrooms. Our interior/exterior Premium Seal sealant is available in both white and black.

Can you paint over a caulked surface once dry, or should you use a primer first?

At KILZ we understand the value of using a primer in your painting projects and will always recommend using one of our KILZ^® branded primers prior to painting. However, in situations where a primer is not available or not preferred, our caulks and sealants can be painted over directly once they are dry. Each product has a different dry time that is indicated on the label to let you know how long you should wait before priming or painting. When applying our KILZ line of caulks and sealants outside, the dried product should always be primed and painted over for best results.

What are the key benefits of using a fast-drying caulk?

The biggest benefit is that you’ll be done with your project much sooner! Our KILZ Quick Dry caulk can be painted with a paint sprayer immediately after application, and only requires a 10-minute dry time before it can be painted with a brush or roller. Compared to 30-minutes or even hours of dry time required by other products in the market, you have an opportunity to save a significant amount of time on your project by using our KILZ Quick Dry fast-drying caulk.

Are there different caulk and sealant products for indoor and outdoor use?

There are! Most (but not all) of our products can be used both inside and outdoors, but some perform better in one or the other. For example, our KILZ Performance Caulk performs best indoor whereas our KILZ Premium Seal is best used for outdoor projects. When using any of our interior/exterior products outdoors, it’s important that they be painted over to achieve the best results. The only product that is specifically stated for indoor use only is our KILZ Waterproof Sealant – this product was not designed or intended to be used outside.

KILZ new line of caulks and sealants includes five new products, can you walk us through each and what types of projects they are formulated for?

• Our KILZ Performance Caulk is a high-quality interior and exterior acrylic caulk that prevents cracking when it’s dry and is easily applied with consistent flow (meaning no air-pops during application). This product is brush/roll paintable in 30-minutes, compatible with all oil and water-based paints, and can be painted using a paint sprayer immediately. This product is great for sealing joints between places like stairs, ceilings, and windowsills, and can be used to fill in cracks and nail holes.

• Our KILZ Quick Dry Caulk is a fast-drying, high-quality interior and exterior acrylic caulk that prevents cracking when dried and is easily applied with consistent flow during application. This unique formula creates a watertight seal and provides excellent adhesion to most common surfaces. This product is instantly paintable with a paint sprayer and can be brush/roll painted in 10-minutes! Similar to KILZ Performance Caulk, it is formulated for sealing joints and filling cracks or holes.  

• Our KILZ All-Purpose Sealant is a premium siliconized acrylic latex with excellent adhesion and weatherability for both interior and exterior use. This easy to apply formula offers outstanding weather durability, has strong adhesion to all common surfaces, and has a high elasticity for flexible joints without cracking or breaking the adhesion bond. This product includes a EPA-registered mildewcide that prevents mold and mildew from forming in the sealant film, and is compatible with all water and oil-based paints. It can be used to seal common surfaces including windows and door frames, baseboards, sinks, tubs, countertops, ceramic tile and other common household projects and surfaces.

• Our KILZ Premium Seal is a non-yellowing, high performance silicone-hybrid sealant built to offer superior stretch and durability on the most dif­ficult surfaces. Built to withstand extreme temperatures, this formula can be applied in both wet and dry conditions, is UV-resistant, is asphalt compatible, and can seal active leaks up to 1/4″ in size. Primary applications include expansion and control joints, sealing roofi­ng and flashing applications, and masonry joints. You can also use this product to seal vinyl windows, door frames and sidings, and other metal building construction and synthetic materials.

• Our KILZ Waterproof Sealant is a versatile, low-odor, mold and has a mildew-resistant 100% Silicone sealant film offering permanent flexibility in a finished seal that will not crack or shrink. Ideal for interior areas that are prone to water exposure, this high-performing durable formula creates a 100% waterproof finish that is water-ready in 10 minutes. It is formulated for use on interior surfaces commonly found in kitchens and bathrooms including metal, wood, glass, drywall, granite, cultured marble, ceramic and porcelain tile and natural stone.

What other tools might you need when using a caulk or sealant?

First thing’s first: you’re going to need a caulking gun. Depending on the type of caulking gun used, you might need to have a safety razor or scissors to cut the plastic tip off the cartridge. For some products, like our Premium Seal and Waterproof Sealant, you’ll need to puncture a foil cap inside the tip. Next, you might want to smooth out or tool the final look of your caulked product by either using a caulking tool or a glove-covered finger. Finally, depending on which product you have, it will be helpful to have a clean rag and some soapy water, or solvent/baby wipes available close by for clean-up.

Always remember to refer to our website kilz.com or product back labels for additional information on which primer is right for your project and detailed instructions on how to apply our products.