Applying a Bead of Caulk Around Doors and Windows is an Easy Way to Prevent Chilly Air and Moisture from Entering Your Home

Many long-range forecasts predict a bad winter across much of the U.S. in 2021-2022. How bad? The venerable Farmer’s Almanac says this winter will be one of the longest and coldest in years and to “prepare for a season of shivers.”

There are many ways you can prepare for the up-coming deep freeze. This includes using more blankets, buying a new high tech winter coat, and turning up the furnace (but with an expected spike in natural gas costs, this may not be the best option).

One of the easiest, most cost-effective ways to keep you house warm and dry this winter is to thoroughly inspect all your windows and doors and apply caulk to any gaps where they meet the house. Even a small gap can decrease the inside air temperature enough to make you feel cold and uncomfortable.

This In The Mix blog provides an overview of caulk types, how caulk is made and how to apply caulk to ensure top performance and appearance.

Types of Caulk

If you’ve walked the aisles of your big box home improvement store, you know that caulk comes in a somewhat dizzying range of formulations. To ensure you have the right caulk for weather sealing, read the label carefully to make sure it is rated for exterior applications. Some of the most common caulk types include:

• Acrylic Latex Caulk

If you own a home, you likely have purchased a tube or two of acrylic latex caulk. You used it to seal around a new sink, fill a gap between a baseboard and wall, or replace a broken shower tile. Acrylic latex caulks dry fast, apply easily, are paintable, and clean up with water (unlike most other sealants). Some acrylic latex caulks are for interior use only while others can also be used outside (although probably not the best choice for durability). Formulations that include silicone have better adhesion and flexibility.

• Pure Silicone Caulk

Silicone caulks can be used for a number of interior and exterior applications. They are flexible, elastic, and stable across many conditions, making them a good choice for weather sealing.

A drawback of silicone caulk is it can be more difficult to use than its acrylic latex cousin. It cannot be cleaned up with water, is harder to smooth and typically cannot be painted. Silicone caulk must also cure before full weather resistance or bonding is achieved. Curing can take anywhere from an hour to several days.

• Polyurethane Caulk

Polyurethane caulks are among the toughest and most tear-resistant sealants making them excellent for areas that get hit by weather the hardest. Many can be painted and fill larger gaps (see label for maximum width) without loosening or falling out. On the downside, it must be over 40° F to apply most polyurethane caulks (with no expected precipitation for a day – although some moisture is required for curing). Some formulations also have a gooey consistency that is difficult to apply and cleanup.

• “Hybrid” Caulk

You probably won’t find a caulk specifically labeled as hybrid. Most caulks in this category combine polyurethane with silicone to provide industry-leading performance. This performance comes at a cost. Hybrid caulks are typically the most expensive. To decide if the cost is worth it, read the label carefully for recommended applications.

• Butyl Rubber Caulk

Butyl rubber is a synthetic rubber that has been used for decades to make a wide variety of products from chewing gum to tires to caulk. When used as caulk, it is waterproof, durable and thick. This makes butyl rubber a great choice for wet locations and filling larger gaps but also hard to apply in colder temperatures.

Butyl rubber caulk adheres to a wide variety of materials including aluminum, wood, stone, fiberglass, vinyl, brick and concrete. It can be used for sealing exterior gutters, corrugated roofing, pipes, aluminum and vinyl siding. Painting it is possible but difficult.

How Caulk is Made

Making caulk is a fairly simple process. Raw materials are combined in a large tank (size varies by manufacturer) and mixed at room temperature for several hours until the desired consistency is achieved. The caulk is then piped into individual tubes and packed into cardboard boxes for shipment.

How to Apply Caulk

When it comes to caulk performance, applying it correctly is just as important as picking the right type. How do you apply it correctly? Carefully read and follow the directions on the label. They provide specific details on the environmental conditions in which the caulk can be applied (e.g., temperature, moisture, sun exposure, etc.), surface preparation, clean-up and other tips to obtain the ideal seal.

The caulk label may also provide instructions on how to achieve the best finished appearance. If not, the steps are relatively simple:

1. Lay the caulk tube on a workbench or hard surface and cut the tip of the tube at a 30-45 degree angle. A utility knife works well for this. The cut should be relatively small for most applications, so excessive caulk does not come out of the tube.
2. Insert the caulk tube in a caulk gun (manual or battery-operated)
3. Apply painter’s tape on both sides of the window or door gap to keep caulk off finished surfaces (optional)
4. Push the plunger into the tube until it stops, touch the tip to the left end of the gap (lefties likely will start with the right end), and squeeze the handle with equal pressure until you reach the other end of the gap.
5. Smooth the caulk with your finger or plastic application tool (found at most hardware and home improvement stores). For latex caulks, you may want to dampen your finger first. For non-latex caulks, dampen your finger with denatured alcohol, rubbing alcohol or mineral spirits. Wipe your finger with a paper towel or rag if caulk builds up on it. Redampen your finger after wiping.
6. Remove painter’s tape and any excess caulk immediately.
7. Allow caulk to dry per label instructions before touching again.

For More Information

ProQuip mixers are used for making caulk and other sealants for commercial and residential applications. For more information on ProQuip mixing solutions, email applications@proquipinc.com or call us at 330-468-1850.

Sources: Family Handyman