Waterproofing brick and mortar protects against wind-driven rain, freeze-thaw damage, and moisture ingress. This guide highlights five top exterior masonry sealers and sealant products to help buyers choose effectively. Best for homeowners tackling older brickwork, chimney surrounds, or new masonry projects, these options balance penetration, breathability, and finish. Each entry notes who it’s best for, why it’s a solid pick, and a simple caution when applicable. Use the quick-reference table below to compare at a glance.
| Product | Best For | Key Strength | Finish |
|---|---|---|---|
| MasonryDefender Chimney Brick Sealer | Breathable exterior masonry | Water-based siloxane | Clear, natural |
| DAP Textured Mortar Sealant | Masonry cracks and holes | Elastomeric latex | Gray, textured |
| Rainguard Brick Sealer | Unpainted brick and mortar | Silane/siloxane | Natural finish |
| Stormdry Brick Sealer Quart | Deep waterproofing protection | Cream-based | Clear |
| Stormdry Brick Sealer 1.5 Gal | Large areas requiring protection | Cream-based | Clear |
MasonryDefender Chimney Brick Sealer
The MasonryDefender Chimney Brick Sealer uses a breathable water-based siloxane formula designed for exterior vertical masonry surfaces, including brick and mortar around chimneys. It is formulated to penetrate while allowing moisture vapor to escape, reducing the risk of trapped moisture that can cause spalling or cracking over time. Best for purists who want a clear, low-contrast finish that preserves brick color. Not ideal for painted surfaces or surfaces with heavy coatings that may hinder penetration. Use on unpainted, unsealed masonry for best results.
Who this is best for: homeowners seeking a clear, breathable seal on exterior brick and chimneys without changing the look. Why chosen: reliable breathability with a water-based formula suitable for continuous exposure to the elements. Caution: ensure surfaces are clean and dry for proper penetration; it may not bond well to painted masonry.
DAP Textured Mortar Premium Elastomeric Sealant
This product is a textured mortar filler and sealant designed to repair cracks and holes in exterior or interior concrete and masonry surfaces. The premium elastomeric latex formula is ideal for mortar, concrete, brick, stucco, and similar substrates. It provides a waterproof and weatherproof seal within 24 hours and becomes paint-ready after 2 hours. It’s best for repairs where flexibility is needed to accommodate movement. The textured gray finish helps blend repairs with existing mortar but may stand out on very smooth or uniform brick.
Who this is best for: DIYers addressing visible cracks or gaps in mortar joints or brick where a flexible, fast-curing sealant is beneficial. Why chosen: combines crack repair and waterproofing in one product with a quick ready-to-paint timeline. Caution: not a deep penetrating sealer; surface prep and priming may be required for porous bricks.
Rainguard Water Sealer Brick Sealer
Rainguard’s brick sealer provides penetrating protection against rain and moisture damage using a silane/siloxane chemistry designed to create a filmless, hydrophobic barrier. It is suitable for a wide range of brick and mortar surfaces and dries with a natural, no-gloss finish that preserves the brick appearance. Its strength lies in resisting wind-driven rain and moisture without altering color. It is best for unpainted surfaces and exterior features like walls, chimneys, and walkways. A potential limitation is the need for proper surface preparation to achieve uniform penetration.
Who this is best for: homeowners who want a natural finish that preserves brick aesthetics while imparting durable water repellency. Why chosen: excellent, invisible protection that minimizes surface sheen. Caution: ensure surface is clean and dry for best penetration; may require reapplication over time in heavy exposure areas.
Stormdry Brick Sealer Quart
Stormdry Brick Sealer is a premium cream-based waterproofing treatment designed to penetrate brick, stone, mortar, cement, sandstone, and granite. It provides deep protection and claims up to 25 years of waterproofing in a single coat. The product is breathable, allowing masonry to dry naturally and preserving thermal properties of cavity wall insulation. It is not suitable for limestone or painted surfaces. Choose this when long-term protection and breathability are priorities, especially on porous masonry.
Who this is best for: project managers or homeowners seeking long-term, deep-penetrating protection with breathable properties. Why chosen: strong protection profile with a single-coat application and decades-long expected performance. Caution: not recommended for painted or limestone surfaces; verify substrate compatibility before use.
Stormdry Brick Sealer Gallon
Stormdry’s gallon option mirrors the quart’s deep-penetration approach with a larger coverage area, offering long-term protection across bigger projects. The cream-based formula penetrates to form a protective barrier while remaining breathable. It is suitable for multiple masonry substrates beyond brick, including stone and cement. Not intended for limestone or painted surfaces. This option is best for large brick-and-mortar installations where consistent, durable protection is needed over many years.
Who this is best for: property owners with extensive brickwork or commercial-like exterior walls needing durable, long-term waterproofing. Why chosen: same robust Stormdry chemistry in a gallon package for efficiency on bigger jobs. Caution: verify substrate compatibility (avoid limestone or painted areas) and follow curing guidelines for best results.
Buying Guide: Key Considerations For Waterproofing Brick And Mortar
What substrate are you treating? Exterior brick, mortar joints, chimneys, or stone all respond differently to sealers. Consider whether you need deep penetration, surface protection, or a breathable, film-free finish. Look for products that balance penetration with vapor permeability to prevent moisture entrapment.
How much area needs protection? For larger homes or commercial properties, gallon-sized or multi-quart packages may be more cost-effective. Be mindful of coverage estimates and reapplication frequency, especially in exposed environments.
Finish preference matters. If you want a natural brick look, choose clear or natural-finish products. If you need to seal gaps and joints, consider elastomeric sealants for durability and flexibility, noting color and texture implications.
Preparation and safety. Clean surfaces thoroughly, remove efflorescence, and ensure dryness before application. Use protective equipment as recommended by the manufacturer, and follow drying times to avoid wash-off or staining opportunities.
Breathability vs. water repellency. The best masonry sealers allow moisture to escape while repelling water. This is crucial to prevent freeze-thaw damage and preserve insulation efficiency in exterior walls.
Frequently Asked Questions
- Do brick sealers change the color of brick? Some sealers are clear and preserve the brick’s natural color; others may slightly darken the surface. Check the finish specification before buying.
- Is a sealant necessary for all exterior brick? Not always. For heavily weathered brick or areas with high moisture exposure, a penetrating sealer can reduce water ingress and damage.
- How long before you can paint after sealing? Some products are paint-ready within a couple of hours, while others may require longer curing. Follow the product’s label guidance.
- Can these be used on interior brick? Most are designed for exterior use; interior applications should consider humidity, ventilation, and the specific product’s compatibility with indoor environments.
- What maintenance is required after sealing? Re-seal as recommended by the manufacturer, typically every several years, depending on exposure and weathering.
- Are there environmental or safety concerns? Use in well-ventilated areas and dispose of any leftover sealant per local regulations. Many products are water-based and low-odor, but always follow safety data sheets.