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Choosing the Right Repair Caulk: Sashco’s Slab vs. Mor-Flexx

It can be confusing to choose the right caulking product when they have a lot in common.

Say you have a concrete crack in your sidewalk, and a crack in your stucco near a window. Sashco makes two great products, both made for these textured surfaces. So which one should you use?

The answer is both.

Yes, Sashco’s Slab® and Mor-Flexx® have some similarities:

How Slab and Mor-Flexx are different

Slab® Mor-Flexx®
Packaging (Yep, they look different.)
Uses Cracks in horizontal concrete, like sidewalks, driveways, garages, basements, and more.
Slab - Where to Use Sidewalk
Cracks in vertical surfaces, like stucco, and the mortar in between brick and stone


Texture Lightly textured to match the texture of concrete More heavily textured to blend in with mortar and stucco
Color 1 color: Gray, to match aged concrete
Slab Color Chart
2 colors: Gray and Beige, to match the most common mortar and stucco colors
Formula Specially formulated:

  • For superb adhesion to concrete
  • With extra elasticity, to handle the extreme movement and heaving that concrete undergoes with changes in temperatures and humidity
Specially formulated:

  • For superb adhesion to brick, stucco, stone, mortar, and other common building materials
  • With extra elasticity, to handle the movement that all normal homes undergo with wind and changes in weather

Can I use Slab in place of Mor-Flexx? Or Mor-Flexx in place of Slab®?

Yes, you may use Slab where you use Mor-Flexx, but it probably won’t match as well as Mor-Flexx. For better overall aesthetics, choose Mor-Flexx. (It’s also costs a bit less.)

No, you may not use Mor-Flexx where you use Slab. It’ll get beat up and damaged by foot and vehicle traffic.

The right product every time

Sashco makes it easy for you to choose the right product for each project around the house. Click here to find your project and the Sashco products that are perfect for you.

See also:

VIDEO: Introducing Slab®: The Serious Fix for Concrete Cracks

VIDEO: How to Fix Cracked Mortar Around a Fireplace

How To Fix Concrete Cracks

How To Repair Cracks in Brick, Stucco, and Mortar

Concrete Crack Repair in 5 Easy Steps

Top 3 Reasons to Use Slab®