Caulking windows is an important part of regular home maintenance. Properly caulked windows keep out drafts, moisture, insects, and noise. With time and shifting foundations, window caulking can crack and peel away, leaving gaps for air and water to seep through. Recaulking windows yourself is an easy weekend project that can make a big difference in the comfort and energy efficiency of your home.

What You’ll Need

Caulking windows is a straightforward process that requires just a few supplies:

• Caulk gun
• Caulk – Siliconized acrylic latex caulk is best for exterior use
• Caulk cutting tool or razor blade
• Paper towels or rags
• Painter’s tape
• Rubbing alcohol
• Putty knife

Make sure to get paintable acrylic latex caulk in a color that matches your window trim. Siliconized acrylic latex caulk adheres well and stays flexible.

Preparing the Surface

Proper surface prep is key to achieving a long lasting seal. Follow these steps to get your windows ready for fresh caulk:

Remove old caulk. Use a caulk cutting tool, putty knife, or razor blade to carefully scrape away all the old caulk. Cut all the way down to the base surface to remove any cracked or loose material.

Clean with rubbing alcohol. Wipe down the area with a paper towel and rubbing alcohol to remove any remaining adhesive, grease, or grime.

Remove dust and debris. Give the crevice a few blasts with compressed air or use a vacuum on a crevice tool setting to remove any remaining dust or debris left from the scraping process.

Widen gaps if needed. For larger gaps due to settling, use a utility knife to cut open the gap slightly and give the new caulk more surface area to adhere to.

Tape off edges. Apply painter’s tape along the length of the window trim or siding above and below the gap. This helps keep the caulk line straight and prevents mess.

Applying the Caulk

With your workspace prepped, it’s time to lay down the new caulk. Follow these tips for smooth application:

Cut nozzle at 45° angle. Cut the caulk tube tip at a 45° angle rather than straight across. This helps the caulk flow out in the right direction and size.

Gun caulk into gap. Hold the caulk gun at a 45° angle with the nozzle inserted deep inside the crevice. Slowly but steadily squeeze out the caulk, keeping continuous pressure on the trigger.

Tool into a concave shape. Once applied, use a putty knife or your finger to shape the caulk into a smooth concave line. This shape allows the caulk to flex as the house shifts and prevents cracks.

Smooth with rubbing alcohol. For a slick perfect finish, dip your finger in rubbing alcohol and run it along the length of the caulk line. The alcohol helps smooth and remove excess.

Remove tape and clean up.Carefully peel away the painter’s tape before the caulk dries. Wipe up any smudges or excess from surrounding surfaces with a paper towel.

Caulking Windows Step-by-Step

Follow this full step-by-step tutorial to properly recaulk drafty windows:

Gather Supplies

You’ll need:

• Caulk gun
• Caulk tube
• Caulk cutting tool
• Putty knife
• Paper towels or rags
• Rubbing alcohol
• Painter’s tape

Siliconized acrylic latex caulk is the best all-purpose choice for exterior window caulking. Make sure the color matches your existing trim.

Prepare the Surface

Start by cleaning and prepping the area:

1. Carefully cut away any cracked, loose, or peeling old caulk with a caulk cutting tool or razor blade. Remove it all the way down to the base surface.
2. Wipe the crevice and surrounding area with a paper towel and rubbing alcohol. This removes any remaining adhesive, oil, or debris.
3. Use short blasts of compressed air or a vacuum crevice tool to remove all dust and particles from the gap.
4. Widen gaps as needed with a utility knife for a better caulk adherence surface.
5. Apply painter’s tape above and below the length of the gap. This keeps lines straight and controls mess.

Apply the New Caulk

With a prepped surface, apply the fresh caulk:

6. Cut the caulk nozzle at a 45° angle for optimal flow control.
7. Insert nozzle deep into crevice and gun caulk in while keeping continuous pressure on the trigger. Keep the caulk gun at 45°.
8. Use a putty knife or finger to shape the caulk into a smooth, concave line.
9. For a perfect finish, dip finger in rubbing alcohol and run along caulk to smooth and remove excess.
10. Remove painter’s tape and wipe up any smudges or mess before caulk dries.

Allow Proper Curing Time

• Allow the caulk to fully cure undisturbed for 24-48 hours before exposing to rain or water.
• The caulk will form a skin in 1-2 hours but takes a full day or more to fully harden and adhere.
• Avoid opening or shutting the window during the curing period.

And that’s it! With a properly sealed gap, your windows will be protected from the elements and drafts. Make caulking windows part of your regular seasonal maintenance for improved comfort and energy savings.

Tips for Caulking Windows

Follow these tips and tricks for getting professional caulking results:

• Caulk in dry weather above 45°F when the gap is at its widest. Cold, wet conditions will inhibit curing.
• Consider using a caulk backer rod for gaps wider than 1/4″. The foam backer fills space and lets the caulk flex.
• Wear latex gloves to keep the caulk from sticking to your skin.
• Hold the caulk gun at a consistent 45° angle and maintain steady pressure on the trigger for smooth flow.
• Test the caulk flow on scrap material first to ensure a proper bead size.
• Tool the caulk with light pressure into a concave shape. Avoid overworking it.
• Make sure caulk fully seals both the exterior and interior edges for full weatherproofing.
• Caulk the full perimeter of each window, not just the horizontal sill and lower gaps.
• Use 100% silicone caulk for areas with prolonged water exposure like around sinks.
• Check for gaps and recaulk as needed each season or after major storms.

Common Window Caulking Problems and Solutions

Window caulking doesn’t last forever and will need maintenance over time. Here are some common caulking problems and how to fix them:

Cracking or peeling caulk: If the caulk appears dried, shrunken and cracked, it needs full removal and replacement. Old latex caulk has a lifespan of 2-5 years.

Pinholes and gaps: Small holes in the caulk line or areas that didn’t get fully sealed will allow air and moisture penetration. Seal with a caulk touch up.

Discolored caulk: White latex caulk can become dingy and yellowed but is still functional. A fresh coat will improve appearance.

Gaps at corners: Special care is required to seal window corners and sill-jamb joints. Use a corner sealant tool or your finger to fully pack the crevice.

Caulk adhering poorly: If new caulk doesn’t stick, the surface wasn’t prepped properly. Scrape away all old caulk and clean the area fully before applying fresh caulk.

Excessive dirt buildup: Dirt stuck in caulk makes removal harder over time. Keep the perimeter of your windows clean to prevent this.

Drafts: Caulk around the full window interior perimeter if air leaks persist after exterior recaulking. Interior storm windows also help.

With routine maintenance and proper application, freshly caulked windows will seal out air and moisture for years. Follow these tips to solve any caulking challenges.

When to Hire a Window Caulking Contractor

While a DIY approach works for most standard window caulking needs, there are some situations where hiring a professional is a good idea:

• Caulking windows more than one story above ground level. Proper scaffolding, harnesses and experience working at heights makes this safer.
• Windows feature decorative trim or architectural profiles. A steady professional hand can best recreate detailed edges.
• Severe surface deterioration requires window prep and repair before caulking. Rotted wood may need replacement.
• Difficult to reach or hazardous locations. Skylights, for example may necessitate special equipment.
• Extensive caulking scope or whole building weatherization. Contractors work faster than DIY on large jobs.
• Historic homes and specialty windows. Knowledge of older window materials and compatibility is key.
• Unfamiliar window or construction types. There are many window variations that specialists are better equipped to handle.

While caulking windows yourself saves money, for challenging situations, hiring a professional can mean better results and safely getting to hard to reach places.

Caulking Windows: Conclusion

Regularly caulking your home’s windows goes a long way in conserving energy and keeping out the elements. With some basic DIY skills, the right caulk, and proper prep, even amateurs can achieve professional-looking results. For maximum window weatherproofing, make sure to caulk fully around the exterior and interior perimeters each year or whenever cracks appear. Follow the techniques outlined above for smooth, long-lasting caulk lines that stand up to the conditions. Your windows are a major weak point for air leaks, moisture, and noise so keep them well sealed with routine caulking maintenance.

Caulk Selection Guide: Choosing the Right Caulk for Your Project

With a wide variety of caulk products available, it’s important to choose the right formulation for your specific application. Here is an overview of common caulk types and usage:

Siliconized Acrylic Latex Caulk

The go-to choice for exterior use and caulking windows. Adheres well to porous and non-porous surfaces, flexible, waterproof and paintable. Ideal for areas exposed to weather such as windows, doors, siding and trim. Available in clear and various colored formulations.

100% Silicone Caulk

Used for areas with prolonged water exposure such as sinks, showers, tubs and plumbing fixtures. Not paintable but extremely durable, flexible and waterproof. Superior adhesion power for wet areas. More difficult to tool into a smooth bead which requires skill.

Butyl Rubber Caulk

A flexible, durable option effective for roof repairs and sealing seams metal ductwork and flashing. Bonds well even under limited prep. Stays somewhat soft and tacky to allow for expansion and contraction. Difficult to use except by skilled pros.

Polyurethane Caulk

Ideal for caulking between dissimilar materials with changing expansion/contraction rates where flexibility is key. Common for wood-concrete joints on house foundations. Limited color options but excellent durability. More difficult to apply than latex.

Epoxy Caulk

Used to seal control joints in concrete slabs, masonry and brickwork. Once hardened, cannot flex or expand/contract. Very strong bond but will crack if substrate shifts significantly. Requires careful surface prep and skill to apply.

Oil-Based Putty

Historically used to install traditional single pane windows. Very soft, pliable and easy to tool. Adheres well to most building materials but relatively weak overall. Requires maintenance to remain sealed so now less common.

Choosing the right caulk comes down to carefully considering the location and your needs. With so many options available, focus on the substrate materials and exposure to elements.

Caulk Colors: Which Finish Should You Choose?

Caulk comes in a variety of color options beyond basic white and clear formulations. Choosing the right finish involves both practical and aesthetic considerations:

• Color-match to your existing trim for seamless, invisible caulk lines along windows, doors, siding and architectural details. Custom colored caulks are available.
• Bright white works for freshly painted white trim and siding. Avoids yellowing over time that can occur with off-white caulk.
• Clear formulations are ideal for natural wood trims and applications where appearance is not a concern. Clear is less paintable than colored caulk.
• Black caulk prevents visibility of dirt buildup over time. Good for perimeter gaps where appearance matters less.
• Metal-toned caulks come in various metallic sheens to match copper, bronze and other architectural metals. Great for sealing flashing and roof joints.
• Grout color caulk mimics the appearance of ceramic tile grout for sealing around tub/shower enclosures. Helps maintain a tidy appearance.

Test your caulk color on scrap material first before applying in visible areas. Allow to fully cure to get an accurate view of the final color. With the many options available today, you can achieve professional results tailored to your needs.

Caulk Finish Options: Matte vs. Glossy

Caulk not only comes in a variety of colors but also different finishes ranging from matte to glossy:

• Matte caulk has a flat, velvety appearance that blends into surfaces. Ideal for visible applications where a smooth finish is desired.
• Gloss caulk has a shiny, wet look when cured. Enhances visibility which can emphasize the caulk line in some cases. Can feel tacky.
• Satin caulk strikes a balance with a soft glow and lower sheen than high-gloss. Provides visibility of the caulk line while blending better than gloss.

Consider if you want the caulk to stand out or recede into the background:

• Gloss makes the caulk line more pronounced which is good for visibility but can look messy if overapplied.
• Matte finishes softly blend in for seamless repairs on finished surfaces.
• Satin offers a compromise of moderate visibility with less glare than high-gloss.

Test gloss, satin and matte caulk finishes on your surface to evaluate the appearance. Apply correctly, any finish will adhere well. The choice comes down largely to visibility and aesthetic preference.

Caulk vs. Sealant: What’s the Difference?

Caulk and sealants are often used interchangeably to mean flexible bonding compounds. However, there are some distinct differences:

Caulk

• Typically latex or silicone based
• Softer consistency, easier to tool and smoothen beads
• More forgiving and paintable
• Ideal for interior use and non-porous materials

Sealant

• Made from denser polymers like polyurethanes
• Harder consistency requiring skill to apply
• Used on exterior, heavy wear situations
• Stronger bonding power but less flexibility
• Ideal for porous, uneven joints

Basic Usage:

• Caulk = Windows, doors, trim, corner joints
• Sealant = Concrete, masonry, wood, brick

While their working properties vary, caulk and sealants both excel at sealing gaps and joints from air and moisture penetration. Usage depends on the specifics of your project.

Caulk vs. Mortar: Key Differences

Mortar and caulk are both used in construction, but have different roles based on their material properties:

Caulk

• Flexible bonding compound for gaps
• Softer consistency, easier to apply
• Remains somewhat elastic when cured
• Effective sealant but lower adhesion strength

Mortar

• Hard bonding agent for masonry materials
• Thick, stiff mixture requiring skill
• Cures hard with almost no flexibility
• High adhesive strength but more brittle

Typical Uses:

• Caulk = Sealing windows, small joints
• Mortar = Structural bonding of masonry blocks

While caulk has some adhesive properties, it is not recommended as a substitute for mortar in structural applications. Mortar joints also require backer rod and sealant for a weathertight finish.

Acrylic Latex Caulk vs. Silicone Caulk

For home caulking projects, the two best options are acrylic latex and silicone caulks. Here’s how they compare:

Acrylic Latex

• Paintable, available in colors
• More affordable, easier to tool
• Sticks to more surface types
• Ideal for indoor/outdoor use
• Less UV and water resistance

Silicone

• Limited color options, not paintable
• More difficult to apply, requires skill
• Superior adhesion and flexibility
• Best for wet areas and outdoors
• More stain resistant but costlier

Recommended Uses:

• Acrylic Latex – Windows, door frames, trim, sidings
• Silicone – Bathrooms, sinks, showers, exterior

For most everyday caulking needs, acrylic latex delivers the best balance of performance and ease of use. Silicone stands up to water better for plumbing, tile and sinks.

Butyl Rubber Caulk Uses

Butyl rubber caulk offers heavy-duty sealing performance in some specialized applications:

• Metal roofs and flashing – The flexible seal prevents leaks even with expansion and contraction. Excellent adhesion to metals.
• Gutters and downspouts – A pliable seal that won’t crack under gutter expansion and contraction over seasons.
• RV and trailer roof seams – Flexible adhesion to the rubber roofing material as vehicles move and shift on roads.
• Ductwork joints – Tape and butyl caulk work together for an airtight, reliable HVAC system seal.
• Chimneys and flues – Maintains a tight seal to prevent exhaust gases from escaping through cracks