How to Seal Concrete: Complete Guide to Concrete Sealers

Why Seal Concrete?

Concrete is porous. Without sealer, water, oil, salt, and other substances penetrate the surface, causing:

• Staining from oil, leaves, rust
• Freeze-thaw damage (spalling, pitting)
• Efflorescence (white salt deposits)
• Mold and mildew growth
• Accelerated wear and deterioration

A quality sealer creates a barrier that extends the life of your concrete and makes maintenance easier.

Types of Concrete Sealers

Penetrating Sealers

These absorb into concrete and react chemically to block water and contaminants from within.

Types: Silane, siloxane, siliconate, silicate

Best for: Driveways, outdoor concrete, areas with freeze-thaw cycles

Pros: Natural look, breathable, long-lasting (5-10 years), no peeling

Cons: Don't enhance appearance, may need multiple coats

Film-Forming Sealers

These sit on top of the concrete, creating a protective coating.

Types: Acrylic, epoxy, polyurethane

Best for: Decorative concrete, interior floors, stamped patios

Pros: Enhance color, add sheen (matte to high-gloss), easy application

Cons: Can peel or wear, need reapplication every 1-3 years, may be slippery when wet

Sealer Comparison

Type	Appearance	Durability	Cost	Best Use
Silane/Siloxane	Natural	5-10 years	$	Driveways, outdoor
Acrylic	Wet look/gloss	1-3 years	$	Decorative, stamped
Epoxy	High gloss	3-5 years	$$	Garage floors
Polyurethane	Satin to gloss	3-5 years	$$	High-traffic interior

When to Apply Sealer

New Concrete

Wait at least 28 days before sealing new concrete. The concrete needs to fully cure, and moisture must escape. Sealing too early traps water and causes problems.

Existing Concrete

Clean thoroughly and ensure surface is completely dry. Test by taping plastic sheeting overnight—if moisture collects underneath, wait longer.

Weather Conditions

• Temperature: 50-90°F ideal
• No rain expected for 24-48 hours
• Low humidity preferred
• Avoid direct sunlight during application

How to Seal Concrete: Step-by-Step

Step 1: Clean the Surface

1. Remove all furniture, planters, etc.
2. Sweep thoroughly
3. Pressure wash (1500-2500 PSI)
4. Remove stains with appropriate cleaners:
   • Oil: Degreaser
   • Rust: Oxalic acid
   • Efflorescence: Mild acid wash
5. Rinse thoroughly and let dry completely (24-48 hours)

Step 2: Repair Cracks and Damage

Fill cracks and patch damaged areas before sealing. Let repairs cure fully.

Step 3: Test Absorption

Sprinkle water on the concrete. If it beads up, there may be old sealer that needs stripping. If it absorbs, you're ready to proceed.

Step 4: Apply First Coat

1. Pour sealer into roller pan or sprayer
2. Start in far corner, work toward exit
3. Apply thin, even coat with roller or sprayer
4. Avoid puddles—thin coats are better than thick
5. Work in manageable sections

Step 5: Apply Second Coat

1. Wait for first coat to dry (check product instructions—usually 2-4 hours)
2. Apply second coat perpendicular to first
3. Maintain thin, even coverage

Step 6: Cure Time

• Light foot traffic: 24 hours
• Heavy use: 48-72 hours
• Vehicle traffic: 72+ hours (check product specs)

Application Methods

Roller Application

Best for most DIY projects. Use a 3/8" nap roller for smooth concrete, 1/2" nap for textured surfaces.

Sprayer Application

Faster for large areas. Use a pump sprayer at low pressure. Backroll immediately to even out coverage.

What NOT to Do

• Don't apply too thick—causes bubbling, peeling, whitening
• Don't apply in direct sunlight—dries too fast
• Don't seal wet concrete—traps moisture
• Don't skip the second coat—one coat rarely provides adequate protection

Maintenance

• Clean regularly with mild detergent
• Reapply sealer when water stops beading
• Penetrating sealers: every 5-10 years
• Film-forming sealers: every 1-3 years

Calculate Your Concrete Area

Before buying sealer, know your square footage. Our concrete calculator can help you determine area and plan your project.