Choosing the right caulk

The Old House Web

While most of us are very choosy when it comes to choosing paint or wallpaper, few give the same thought to the caulk we buy.

Yet purchasing the right caulk -- and knowing how and when to use it -- is one of the most important investments a homeowner can make.

Properly applied, this simple product helps protect the entire home from moisture damage, all the while increasing its energy efficiency.

Caulk basics

The basic purpose of every caulk or sealant is the same: to provide a watertight and airtight seal. But when it comes to fulfilling this promise, not all caulks are created equal.

To be effective, a caulk must have excellent adhesion characteristics, enabling it to stick to a variety of building materials, including wood, ceramic tile, concrete, glass, plaster, aluminum, brick and plastic, even under wet conditions.

For superior adhesion to the widest range of surfaces, nothing beats a water-based all-acrylic or siliconized acrylic caulk, according to the experts at the Paint Quality Institute, who have been testing caulks for more than 30 years. Moreover, these types of caulks have better adhesion to wet surfaces than do latex or vinyl caulks.

To maintain a watertight and airtight seal over time, caulk must also be flexible, so that it can act like a "shock absorber" to accommodate the movement of building materials as they expand and contract with temperature changes. This, too, is an attribute of water-based all-acrylic or siliconized acrylic caulks.

But it's not enough for a caulk to have good initial adhesion and flexibility. It must maintain these qualities over time, or the caulk could crack and pull away from the surfaces to which it is applied. Again, tests show that water-based all-acrylic and siliconized acrylic caulks excel in terms of long-term durability, which makes them a great investment in terms of cost-per-year-of-service.


Then there is the question of appearance.

Few homeowners ever notice their caulk until it becomes soiled or full of mildew. When it does, they realize how caulk can make or break the aesthetics of a bath, kitchen, family room, or the exterior of their house.

Top quality all-acrylic and siliconized acrylic caulks are specially formulated to maintain an attractive appearance even after years of service. They are resistant to dirt and mildew. They are bright white or clear and remain so over time. And, unlike silicone caulks, they can be painted with all types of paint.

So, the next time you go out to buy caulk, remember that all caulks are not created equal. According to the experts, your best overall value is a water-based all-acrylic or siliconized acrylic caulk. It may cost only slightly more, but it will perform like a million bucks!

For more information on top-quality all-acrylic or siliconized acrylic sealants, the Paint Quality Institute suggests that you ask for help at your local home center, hardware store, paint store or Decorating center.

Interior finishing

Do you think of caulk as an exterior product only? Think again. Contractors often use caulk inside the home to give rooms a visually pleasing, "finished" look.

In virtually every home, there are gaps where molding contacts the walls or where two pieces of molding come together. Since most paints will not fill gaps larger than 1/16", contractors seal these spaces with caulk, which is easier to use than either wood filler or spackle when you plan to paint over the molding.

Here are some of the places to apply caulk for finishing purposes:

  • around crown molding, chair rails and baseboards;
  • around door and window frames;
  • in mitred corners (gaps where two pieces of molding come together at an angle)
  • to fill small wall cracks.

Waterproofing the ktchen and bath

Caulk is used to protect the kitchen, bath and laundry from the damaging effects of water. Water seeping down into the walls, wallpaper, cabinets and floors can result in thousands of dollars of damage. But by sealing with caulk, you can create a waterproof barrier that is also attractive.

Areas in the kitchen that will benefit from caulking include:

  • where the countertop meets the splashboard;
  • where the splashboard meets the wall; and
  • where the sink meets the countertop.

In the bathroom, caulks can be used to provide a watertight seal around sinks, shower stalls, toilets and bathtubs.

Exterior weatherproofing

Caulk is used on the home's exterior to seal out moisture and outside air; at the same time, it helps keep costly heat and air conditioning indoors.

Were it not for the tight moisture barrier created by caulking, rain and snow could seep into gaps and joints, causing wood to rot and paint to blister.

Areas that may need exterior sealing include those where:

  • window and door frames meet siding or an exterior wall;
  • wood panels come together around window and door frames, especially where vertical frames contact the sill plates;
  • different types of building materials meet, e.g. wood siding against brick;
  • siding meets foundation;
  • wood, vinyl or aluminum siding forms corner joints;
  • gaps and cracks are present in siding, stucco, masonry or foundation; and
  • there are vent ducts, air conditioners, and openings for plumbing or wiring.

This information is brought to you by The Paint Quality Institute. For more advice on home painting, talk to a knowledgeable salesperson at your local paint store, hardware store or decorating center. Or visit the Paint Quality Institute Web site at www.paintquality.com.

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