MEL-ROL LM vs. MEL-ROL LIQUID MEMBRANE: Understanding the Difference

When selecting a waterproofing product, similar product names can sometimes create confusion, especially when the products perform very different functions.

Two W. R. MEADOWS products with similar names are MEL-ROL LM and MEL-ROL LIQUID MEMBRANE. Although both are liquid-applied materials and both carry the MEL-ROL name, they are not interchangeable products.

The most important distinction is simple:

MEL-ROL LM is a waterproofing membrane designed to waterproof the entire below-grade vertical surface. MEL-ROL LIQUID MEMBRANE is a detailing material designed for use with the MEL-ROL sheet-applied waterproofing system. MEL-ROL LIQUID MEMBRANE is not a detailing component of the MEL-ROL LM system and should not be substituted for the detailing products specified for MEL-ROL LM in its current product data sheet. Understanding the role each product plays is important when specifying, purchasing, and installing the appropriate waterproofing system.

 

What Is MEL-ROL LM?

MEL-ROL LM is a single-component, polymer-modified, cold-applied, water-based liquid waterproofing membrane. It is designed for below-grade vertical seamless waterproofing applications.

Rather than installing sheets of waterproofing membrane across the wall, MEL-ROL LM is applied directly to the substrate by roller or airless sprayer. Once properly applied, the material forms the primary waterproofing membrane across the surface.

MEL-ROL LM can be used for both new construction and remedial waterproofing applications over concrete and masonry block substrates. Because it is water-based, it can also be used with insulated concrete forms (ICFs) and on “green concrete.”

One of the advantages of a liquid-applied system is its ability to create a seamless waterproofing layer. MEL-ROL LM is fully bonded to the substrate, provides very low vapor permeability, and offers high elongation to help bridge minor cracks. Its single-component formulation also eliminates the need to combine separate components before installation.

Depending on the project, MEL-ROL LM may be incorporated into a broader waterproofing assembly with protection course, insulation, drainage board, or other compatible system components.

Most importantly, however, MEL-ROL LM is the waterproofing membrane itself.

What Is MEL-ROL LIQUID MEMBRANE?

Despite what its name might initially suggest, MEL-ROL LIQUID MEMBRANE serves a much different purpose. It’s a two-component, 100% solids, cold-applied, non-slump detailing material used as part of the MEL-ROL sheet-applied “peel-and-stick” waterproofing system, along with our PRECON and HYDRASTOP SA systems.

MEL-ROL LIQUID MEMBRANE is used for specific detailing conditions rather than as the primary waterproofing membrane across the entire wall. Typical applications include forming fillets, reinforcing corners, and creating flashing details. It is also suitable for use underneath MEL-ROL sheet membrane.

Its non-slump consistency allows the material to be troweled where additional detailing is needed. Depending on the condition being addressed, it can be applied around corners, terminations, drains, protrusions, and other areas where a liquid detailing material helps maintain continuity within the sheet waterproofing system.

Once cured, MEL-ROL LIQUID MEMBRANE forms a tough, flexible membrane but its role within the system remains detailing, rather than serving as the primary field-applied waterproofing membrane.

The Difference Comes Down to Function

An easy way to distinguish between the two products is to ask one question: “Are you waterproofing the surface, or detailing a MEL-ROL sheet membrane installation?”

If the project requires a liquid-applied waterproofing membrane across a below-grade vertical surface, MEL-ROL LM is designed for that purpose.

If the project uses MEL-ROL sheet waterproofing and requires a liquid material for specific details, MEL-ROL LIQUID MEMBRANE may be appropriate.

That distinction is particularly important because the word “liquid” appears in both product descriptions. The fact that a product is liquid-applied does not necessarily mean it is intended to serve as the primary waterproofing membrane across an entire substrate.

They Are Not Companion Products

Another important misconception is that MEL-ROL LIQUID MEMBRANE should be used to detail MEL-ROL LM. It should not.

The MEL-ROL LM system has its own detailing procedures and compatible products. For example, W. R. MEADOWS recommends addressing inside corners with a cove of BEM before applying MEL-ROL LM. Crack pretreatment, coating thicknesses, and the appropriate detailing products depend on substrate condition and must follow the crack-width thresholds and procedures set out in the current MEL-ROL LM product data sheet.

The required membrane coverage at inside and outside corners, non-moving and hairline cracks, drains, and penetrations is specified in the current MEL-ROL LM product data sheet and should be confirmed for each project. In other words, choosing MEL-ROL LM does not mean selecting MEL-ROL LIQUID MEMBRANE as its liquid detailing companion simply because the products share the MEL-ROL name.

MEL-ROL LIQUID MEMBRANE belongs with the MEL-ROL sheet waterproofing system, while MEL-ROL LM is a separate liquid-applied waterproofing approach.

Why Proper Product Selection Matters

Waterproofing performance depends on more than selecting a product labeled “waterproofing.” Each component of a system has a specific purpose, installation method, required thickness, and relationship to surrounding materials.

Using a detailing product as though it were a field membrane, or assuming two similarly named materials are designed to work together, can result in an installation that does not match the intended system design.

Before beginning a waterproofing project, identify the type of system being installed.

For a liquid-applied below-grade vertical waterproofing system, MEL-ROL LM provides the primary waterproofing layer and can be roller- or spray-applied. It should be applied at the coverage rates and wet-film thicknesses specified in the current MEL-ROL LM product data sheet.

For a MEL-ROL sheet-applied waterproofing system, MEL-ROL LIQUID MEMBRANE can provide localized detailing where required, including corners, fillets, flashing, terminations, drains, and protrusions.

These are two different approaches, and the products should be selected based on their intended role within the specified waterproofing system.

Know the System Before You Choose the Product

Remember the distinction:

MEL-ROL LM = liquid-applied waterproofing membrane.

MEL-ROL LIQUID MEMBRANE = liquid detailing material for the MEL-ROL sheet waterproofing system along with PRECON and HYDRASTOP SA systems.

Keeping those roles separate helps ensure that each material is used where it was designed to perform. Waterproofing systems involve many variables, including substrate conditions, detailing requirements, drainage, protection, environmental conditions, and project specifications. Always consult the current W. R. MEADOWS product data sheets and installation instructions before application. For project-specific questions or assistance selecting the appropriate waterproofing system and detailing materials, contact W. R. MEADOWS Technical Services.

Request More Information

To contact your local W. R. MEADOWS representative or for general correspondence, please click here. If you need immediate assistance, please call (800) 342-5976. Thank you!