If rainwater is sneaking under or around your door, you’re not alone. We see this all the time across Oshawa, Ajax, Pickering, and Toronto—especially after heavy spring storms or wind-driven rain. In our experience, most door leaks aren’t caused by one big failure. They’re usually the result of small gaps, worn seals, or aging caulking that’s quietly stopped doing its job.
Here’s what actually works when it comes to sealing a door from rain, based on what we’ve seen in real homes, not theory.
Rain Leaking Under Your Door? Proven Ways to Seal Doors Properly
One homeowner in Pickering called us after placing towels at their front door every time it rained. The issue wasn’t the door itself. It was a compressed bottom seal and cracked door threshold caulking that let water funnel inside.
The most common causes of rain leaks include
• Shrunk or missing door bottom seals
• Cracked or peeling caulk along the frame
• Gaps at the door threshold
• Poor slope or drainage near the entry
Fixing these issues early prevents flooring damage, mold, and long-term structural repairs.
How to Seal Doors Against Rain and Wind | Home Weatherproofing Guide
Rain rarely falls straight down. Wind pushes it sideways, forcing water into places it shouldn’t be. That’s why exterior door weatherproofing needs to address all sides of the door, not just the bottom.
In our work, effective rain protection door sealing usually includes
• Tight door frame caulking to block wind-driven moisture
• A flexible bottom seal that stays snug year-round
• Properly sealed thresholds that shed water outward
When these elements work together, water stays outside where it belongs.
Door Leak Prevention 101: How to Keep Rainwater Outside
Door leak prevention isn’t complicated, but it does need to be done right. Here’s what we recommend homeowners check at least once a year.
Start with a visual inspection
• Look for cracks or gaps in caulking
• Check if the bottom seal is flattened or brittle
• Feel for drafts during windy rain
Then test it
• Spray water along the door edges
• Watch for moisture on the interior side
If you see water coming in, you likely need door rain leak repair rather than a full replacement.
Best Ways to Seal Exterior Doors From Rain Damage
We’ve personally tested many sealing methods over the years. These consistently deliver the best results.
Door threshold caulking
High-quality exterior caulk seals the joint between the threshold and flooring, stopping water from wicking inside.
Door bottom seal replacement
If light or air passes under the door, water will too. A new bottom seal is often the fastest fix for water coming under a door.
Frame sealing
Small gaps around the frame allow rain to travel behind trim and into walls. Professional door caulking closes those paths permanently.
These steps protect your home and extend the life of your door.
How to Fix Water Leaks Around Doors | Caulking & Bottom Seal Solutions
A Toronto client recently assumed their door needed replacing. After inspection, we found the issue was failed caulking hidden behind trim. Once resealed, the leak stopped immediately.
This is why an exterior door sealing service often saves money. Targeted repairs fix the problem without unnecessary replacements.
Common fixes we use include
• Removing old, hardened caulk
• Applying new weather-flexible sealant
• Installing properly sized bottom seals
The result is a clean finish and real protection.
Rain Protection for Exterior Doors: What Actually Works
DIY fixes can help in mild cases. But not all solutions last.
Temporary fixes that don’t hold up
• Tape or foam stuffed under doors
• Interior caulking for exterior leaks
• Cheap seals that crack in winter
What works long-term
• Exterior-rated caulking applied correctly
• Professionally fitted bottom seals
• Full door leak prevention service
Ontario weather demands materials that flex through freeze-thaw cycles.
How to Stop Rain From Coming Under Your Door Threshold
If water enters at the threshold, the fix usually involves more than one step.
Effective threshold sealing includes
• Cleaning and resealing the threshold joint
• Ensuring the threshold slopes outward
• Pairing with a tight bottom seal
When done properly, this stops pooling and prevents water from being pushed inside during storms.
Sealing Doors Against Heavy Rain: DIY Fixes vs Professional Caulking
DIY can work if
• The gap is small
• The damage is minimal
• You use the right materials
Professional door caulking is the better choice when
• Leaks return after DIY attempts
• Water enters during heavy rain
• You want a long-term solution
We’ve seen many homes where quick DIY fixes masked deeper problems. Professional sealing addresses the root cause.
Door Bottom Seals and Caulking: The Complete Guide to Rain Protection
True exterior door weatherproofing relies on two things working together.
Bottom seals stop water from pushing underneath.
Caulking blocks moisture from entering around the frame and threshold.
When either fails, rain finds a way in. When both are properly installed, doors stay dry, energy bills drop, and interiors stay protected.
If you’re dealing with leaks, drafts, or water damage, we can help. Kettle Contracting provides professional door caulking and exterior door sealing services across Oshawa, Ajax, Pickering, and Toronto. Contact us today to schedule an inspection and finally fix water coming under your door—for good.
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