Stop the Drafts: How to Seal Cracks Around Old Window Frames
Old windows have character, but they also tend to let in cold air, heat, bugs, and moisture. Small cracks around window frames may not seem like a big deal, but they can slowly increase energy bills and make your home uncomfortable.
The good news? Sealing those cracks is a simple DIY job. You don’t need special skills, and most projects can be done in an afternoon. This guide walks you through the step-by-step process of sealing cracks around old window frames.
Why Sealing Old Window Cracks Matters
Cracks around window frames may seem minor, but they can cause real problems:
- Drafts that make rooms colder or hotter
- Higher heating and cooling costs
- Moisture getting into walls
- Paint peeling or wood damage
- Bugs finding their way inside
Sealing these gaps helps protect your home and makes it more comfortable year-round.
Tools and Materials You’ll Need
Before you start, gather these basic supplies:
- Caulk (latex or silicone, depending on the gap)
- Caulking gun
- Utility knife or scraper
- Putty knife
- Old rags or paper towels
- Mild cleaner or soapy water
- Weatherstripping (for larger gaps or moving parts)
Most of these are inexpensive and easy to find at any hardware store.
Step 1: Inspect the Window Frame
Take a close look around the inside and outside of the window.
Check for:
- Visible cracks or gaps
- Old, cracked, or peeling caulk
- Areas where air seems to come through
A simple trick is to hold your hand near the edges on a windy day or use a lit incense stick to spot airflow.
Step 2: Remove Old Caulk and Debris
New caulk won’t stick well to old, damaged material.
- Use a utility knife or scraper to remove loose or cracked caulk
- Scrape gently to avoid damaging the frame
- Wipe the area clean with a damp rag
- Let it dry fully before moving on
This step makes a big difference in how long the repair lasts.
Step 3: Choose the Right Caulk
Not all caulk is the same.
- Latex caulk is easy to use and paintable, great for small indoor gaps
- Silicone caulk is better for moisture and outdoor use, but harder to paint
For old windows, flexibility matters. Look for caulk labeled for windows and doors.
Step 4: Apply the Caulk
Now for the main job.
- Cut the tip of the caulk tube at a small angle
- Load it into the caulking gun
- Apply steady pressure and run a smooth bead along the crack
- Work slowly to avoid gaps or bubbles
Don’t worry if it’s not perfect right away.
Step 5: Smooth and Clean the Seal
- Use a damp finger or putty knife to smooth the caulk
- Wipe away excess before it dries
- Let it cure according to the instructions on the tube
A clean, smooth seal not only works better, it looks better too.
Step 6: Add Weatherstripping if Needed
If the window itself moves or has gaps when closed, caulk alone may not be enough.
- Apply weatherstripping along the sash or frame
- Make sure the window still opens and closes easily
- Replace old or flattened weatherstripping as needed
This extra step helps block drafts and noise.
Common Mistakes to Avoid
- Applying caulk over dirty or wet surfaces
- Using the wrong type of caulk
- Sealing weep holes that allow water to drain
- Rushing the job without smoothing the bead
Taking your time pays off here.
Final Thoughts
Sealing cracks around old window frames is one of the easiest ways to improve comfort and cut energy waste. It’s affordable, beginner-friendly, and makes an immediate difference you can feel.
A few simple tools, a little patience, and an afternoon of work can help your old windows perform much better without replacing them. Small fixes like this go a long way in keeping your home cozy and protected.
If you’re tackling more DIY projects, start with the ones that save you money and make your space more comfortable. This is one of them.