Having a gap between your sliding doors and the wall can allow outside air, insects, and noise to infiltrate your home. Filling the gap is an easy DIY project that can make your home more comfortable and energy efficient.
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What causes sliding door gaps?
There are a few common causes of gaps around sliding doors:
- Settling of the house over time
- Improper installation of the original door
- Warping or shifting of the door or frame from temperature changes
- Wear and tear on the door rollers and track
Normal settling of a house over the years can cause the door frame to shift slightly, creating a gap between the door and the wall. Doors that were not properly shimmed and secured into the opening during the original installation are also prone to develop gaps from movement and vibration.
Temperature and humidity changes cause sliding doors, especially wood doors, to expand and contract. This fluctuation allows gaps to form over time as the dimensions of the door alter. Metal rollers and tracks can also deform minimally from repeated use, allowing the door to sag and no longer fit flush.
Should you fill the gap?
Here are some reasons why filling a sliding door gap is recommended:
- Prevent air drafts – Gaps allow uncomfortable drafts into the home that can increase heating and cooling costs.
- Keep out pests – Insects and rodents can squeeze through small exterior door gaps and get into the home.
- Reduce noise – Gaps mean less noise reduction from outside sounds like traffic or noisy neighbors.
- Improve insulation – Filling gaps improves the air sealing of the home.
- Enhance appearance – Door gaps look unsightly and create visible light gaps along the edges.
Fixing sliding door gaps should be part of regular home maintenance to maintain energy efficiency and comfort. The good news is it’s an inexpensive project that can be completed in under an hour in most cases.
How to measure the gap
Start by measuring the width of the gap along the top and sides of the door. Use a ruler, tape measure, or a thickness gauge to determine the gap width.
Check the gap with the sliding door closed, open halfway, and fully open to measure any variation. Also measure from multiple spots, since the gap may not be consistent along the entire length.
The most common sliding door gap widths are:
- 1/8 inch
- 1/4 inch
- 3/8 inch
- 1/2 inch or larger
Measuring will help determine what size filler material you need. For very thin gaps under 1/8 inch, you may only need weatherstripping. Wider gaps will require thicker sealant foam or rubber strips.
What materials fill sliding door gaps?
Here are some common options for DIY materials to fill the gap:
Weatherstripping
Weatherstripping is an inexpensive flexible trim made from vinyl, rubber, foam, felt, or a combination of materials. It comes in various widths and thicknesses.
Benefits:
- Inexpensive
- Easy to install
- Good for small gaps under 1/4 inch
Drawbacks:
- Less durability than sealants
- Can still allow some airflow
Silicone sealant
Silicone caulk and sealants are flexible synthetic rubber compounds that dry permanent and waterproof. They come in tubes or cans.
Benefits:
- Seals out air and moisture
- Long lasting flexibility
- Works on gaps up to 1 inch
Drawbacks:
- Can be messy to work with
- Strong fumes during application
Foam sealant
Expanding polyurethane foam is available in pressurized cans. As it cures, it expands many times original size to fill gaps. Foam can be trimmed after drying.
Benefits:
- Customizable for large gaps
- Highly insulative
- Good stopping drafts
Drawbacks:
- More expensive
- Will expand beyond gap if not constrained
- Difficult to make neat
Rubber door seal
Adhesive rubber strips specifically made to seal door gaps. Can be cut to length.
Benefits:
- Self adhesive for easy installation
- Compresses to seal gap
- Neat finish
Drawbacks:
- Only for smaller gaps less than 1/2 inch
- Not as durable as silicone
The best sliding door gap filler depends on your specific gap size and whether you want a permanent or temporary solution. Weatherstripping and rubber seals work well for small gaps that need easy periodic replacement. Silicone and foam provide a more heavy duty seal for wide or uneven gaps.
How to fill sliding door gaps
Follow these basic steps to fill sliding door gaps:
Prep the area
Use a utility knife to remove any existing sealant or weatherstripping. Scrape and sand the opening to remove paint and debris. Wipe clean the surface with a cloth. Mask off the areas around the gap.
Test fit the sealant
Hold the weatherstripping, foam, rubber strip, or backing rod for silicone against the opening to gauge the right thickness needed. Cut sections to fit each side and top gap.
Install the sealant
For weatherstripping, peel off adhesive backing and press into place along each side and top gap. For silicone, apply with a caulk gun and tool smoothly. Use foam backer rod to limit depth. For can foam, brace board against open gap to contain expansion.
Clean up
Remove masking tape and clean excess silicone or foam with a razor. Slide door back and forth to test movement. Let foam cure completely before trimming flush.
Tips for a successful sliding door gap fill
- Clean all debris and dirt from the gap for best adhesion
- Use painter’s tape to keep the area neat during application
- Read sealant directions carefully for dry times and expansion rates
- Cut sealants slightly longer than measured to compress into the gap
- Tool silicone with a wet finger or caulk tool for a smooth finish
- Make sure door can still open fully once gap is filled
Taking your time to properly fill sliding door gaps results in a seals that will last for years. Correctly sealing the gap improves energy efficiency, keeps out pests, and helps control indoor temperature and humidity levels.
Other methods to reduce air gaps
In addition to gap fillers, here are some other options for minimizing air leaks:
Adjust or tighten rollers
Check for loose or worn out sliding door rollers. Tighten any loose screws securing the rollers. Consider replacing sagging rollers to raise the door.
Lubricate rollers and track
Use a light oil or lubricant like WD-40 to reduce friction and any squeaking or grinding from metal rollers. Keeping the track clean and lubricated helps the door operate smoothly.
Add door sweeps
Installing bristle or rubber sweeps along the bottom of the doors seals the gap below the track. This helps prevent drafts even when the gap along the top and sides has been filled.
Replace weatherstripping
Check door weatherstripping around the frame and replace any sections that are worn out or missing. Dense weatherstripping will still allow smooth operation.
Adjust strike plate
If gap is uneven, adjust strike plate inwards so the door seals tighter when closed. May require filling old screw holes and redrilling.
Conclusion
Filling sliding door gaps is an important sealing task that can reap big comfort and efficiency rewards. With the right materials and some careful installation, you can prevent annoying air leaks for under $30 in materials. Just be sure to clean thoroughly, measure precisely, and use long lasting flexible sealants. Paying attention to proper door weatherstripping and hardware maintenance also ensures the best performance. Give your home an energy upgrade and stop drafts by taking time to seal those sliding door gaps this season.
| Material | Best for gap size | Durability | Cost |
|---|---|---|---|
| Weatherstripping | Under 1/4 inch | 1-3 years | $-$$ |
| Silicone sealant | 1/4 inch to 1 inch | 10+ years | $$ |
| Foam sealant | Over 1/2 inch | 5-10 years | $$ |
| Rubber door seal | Under 1/2 inch | 3-5 years | $ |
Related Questions
What are signs you need to fill a sliding door gap?
Signs that indicate a sliding door needs new gap filling include:
- Visible daylight around the edges
- Noticing bugs and insects getting in
- Feeling drafty air from the gap
- Seeing weatherstripping damaged or missing
- Hearing outside noise coming through the gap
- Seeing uneven gap widths along the opening
What tools do I need to fill sliding door gaps?
Helpful tools include:
- Tape measure
- Utility knife
- Caulk gun
- Rubber mallet
- Putty knife
- Backer rod
- Sandpaper
- Safety razor
- Masking tape
Should I replace the weatherstripping or just fill the gap?
It’s best to do both for a complete seal. Filling the gap blocks infiltration through the space itself. But worn weatherstripping should still be replaced to seal the edges around the frame. New weatherstripping combined with gap filler provides optimal protection.
What kind of silicone is best for sliding glass doors?
Look for 100% silicone sealant that lists glass and metal compatibility. Try to find silicone rated for wide temperature ranges for durability. A non-corrosive neutral cure silicone works well for doors. Clear silicone blends in along the edges.
How long does silicone take to dry before closing sliding door?
It’s best to wait 24-48 hours for the silicone to fully set and dry before closing sliding doors. This prevents sticking and allows a complete bond. If gap filling both sides, seal one side and allow to dry before doing second side. Follow manufacturer’s drying recommendations.