FAQs

A. HOW CAN I WATERPROOF A FLAT NON-WALKABLE ROOF?

The No Crack Asphalt Membrane, containing Megaflex Plastic Cement and an aluminum composite coating, is recommended for waterproofing flat non-walkable roofs.
Recommended products for this purpose include:

For an efficient and lasting waterproofing, follow these instructions:

  • Check the surface to be waterproofed: It must be perfectly clean, dry, tough, and smooth. The surface should have a suitable slope and the necessary drains to allow for proper water drainage. Avoid the presence of holes, bumps, or slopes that might result in water stagnation over the waterproof membrane.
  • Properly clean the surface by removing dust, dirt and other residues. Then, prime the surface using the solvent-based Megaflex Asphalt Painting or the aqueous Megaflex Asphalt Emulsion, according to surface conditions. This will not only improve the membrane adhesion, but also double its durability. (Yield: 0.5 L/m2; applying two coatings.)
  • Allow the primer to dry and then proceed to install the No Crack Membrane. For that purpose, first fully apply the asphalt membrane using a torch. This will increase both the waterproofing strength and durability. The remaining rolls must be successively placed up from one another, from bottom to top, perpendicular to the slope, and overlapping one another to achieve watertight integrity. The joints and the exudation in between are then sealed to avoid any possible leak between rolls.
  • Finally, the joints should be painted with Megaflex Aluminized Asphalt Painting to protect the exuded asphalt and prevent its early decay, increasing the membrane lifespan by several years. (Yield: 1 L per 80 m2).
For further information, see Megaflex Installation Manual or IRAM Guideline #12627 (Installation guidelines for pre-manufactured asphalt membranes).

B. HOW CAN I WATERPROOF A WALKABLE ROOF?

Geotrans Walkable Membrane is a waterproofing product recommended for surfaces exposed to frequent or occasional transit or needing mechanical strength to be protected against abrasion, traction and punching strains. Geotrans Walkable Membraneis reinforced with Megaflex Plastic Cement and Geotextile coating (woven polyester fiber).
These are the proper installation steps:

  1. Check the surface to be waterproofed: It must be perfectly clean, dry, tough, and smooth. The surface should have a suitable slope and the necessary drains to allow for proper water drainage. Avoid the presence of holes, bumps, or slopes that might result in water stagnation over the waterproof membrane.
  2. Properly clean the surface by removing dust, dirt and other residues. Then, prime the surface using the solvent-based Megaflex Asphalt Painting or the aqueous Megaflex Asphalt Emulsion , according to surface conditions. This will not only improve the membrane adhesion to the area but also double its durability. (Yield: 0.5 L/m2, applying two coatings.)
  3. Allow the primer to dry and then proceed to install the Geotrans Walkable Membrane. The joints and the exudation in between are then sealed to avoid any possible leak between rolls.
  4. Finally, paint the entire membrane with Geotrans Paint , thus protecting the geotextile reinforcement and doubling the coating mechanical strength. Geotrans Paint allows membrane transitability and prevents its early decay, both extending its durability and providing a finely aesthetic red, green, or white finish. (Yield: 0.5 L/m2 in two coatings.)
For further information, see Megaflex Installation Manual or IRAM Guideline #12627 (Installation guidelines for pre-manufactured asphalt membranes).

C. HOW CAN I WATERPROOF A METAL OR TILE ROOF?

The No Crack Asphalt Membrane is recommended for waterproofing a pitched metal or tile roof. No Crack Asphalt Membrane is made with Megaflex Plastic Cement and an aluminum composite coating.
Recommended products for this purpose include:

For an efficient and lasting waterproofing, follow these instructions:

  • Check the surface to be waterproofed: It must be perfectly clean, dry, tough, smooth, and uniform.
  • Properly clean the surface, removing rust, dust, dirt and other residual material. Then, prime the surface by using solvent-based Megaflex Asphalt Paint , which will improve membrane adhesion, doubling its durability. (Yield: 0.5 L/m2 in two coatings.) The asphalt paint also functions as an anti-corrosion coating, protecting the surface and extending the roofing durability. For that purpose, first fully set down the asphalt membrane using a torch, fitting the membrane over the surface shapes. This will ensure resistance and waterproofing durability. The remaining rolls must be successively placed up from one another, from bottom to top, perpendicular to the slope, and overlapping one another to achieve watertight integrity. The joints and the exudation in between are then sealed to avoid any possible leak between rolls.
  • Finally, the joints should be painted with Megaflex Aluminized Asphalt Paint to protect the exuded asphalt and prevent its early decay, increasing the membrane lifespan by several years. (Yield: 1 L per 80 m2).
For further information, see Megaflex Installation Manual or IRAM Guideline #12627 (Installation guidelines for pre-manufactured asphalt membranes).

D. HOW CAN I WATERPROOF UNDERSLAB OR UNDERCOURSE SURFACES?

The Megaflex Aluminum-Free Asphalt Membrane, also called normal membrane, is recommended whenever the waterproof membrane is to be integrated into an underslab or undercourse system. Megaflex Aluminum-Free Asphalt Membrane is made with Megaflex Plastic Cement and a high-density polyethylene coating.
Recommended products for this purpose include:

These are the proper installation steps:

  • Check the surface to be waterproofed: It must be perfectly clean, dry, tough, and smooth. The surface should have a suitable slope and the necessary drains to allow for proper water drainage.
  • Properly clean the surface by removing dust, dirt and other residues. Then, prime the surface using the solvent-based Megaflex Asphalt Painting or the aqueous Megaflex Asphalt Emulsion , according to surface conditions. This will not only improve the membrane adhesion but also double its durability. (Yield: 0.5 L/m2, applying two coatings.)
  • Allow the primer to dry and then proceed to install the Megaflex Membrane. For that purpose, first fully apply the asphalt membrane using a torch. This will ensure resistance and waterproofing durability. The remaining rolls must be successively placed up from one another, from bottom to top, perpendicular to the slope, and overlapping one another to achieve a perfect seal. The joints and the exudation in between are then sealed to avoid any possible leak between rolls.
  • Finally, the membrane is sanded by melting the polyethylene coating and sprinkling sand to improve the screed adhesion onto the asphalt membrane.
For further information, see Megaflex Installation Manual or IRAM Guideline #12627 (Installation guidelines for pre-manufactured asphalt membranes).

E. WHAT IS AN ASPHALT MEMBRANE?

An asphalt membrane is a multi-ply ready-made product that is normally used for waterproofing roofs, decks and various surfaces. Asphalt membranes are made of the following elements:

  1. Coating: Provides protection to the asphalt layer, preventing early decay from exposure to ultraviolet rays. The type of coating will depend on the membrane expected use.
  2. Asphalt Layer: Made with Megaflex Plastic Cement, the asphalt layer is a waterproof lasting material that withstands high stretch and stress. The ready-made membranes may have either one or two asphalt layers, according to their thickness.
  3. Core: Confers strength and uniformity to the membrane. It may be made of high density polyethylene or polyester geotextile.
  4. Anti-adherent film: A polyethylene film which enables membrane winding during manufacture.

The asphalt membrane is a waterproofing system comprising three basic elements— priming, membrane and surface finish.

F. HOW MANY TYPES OF ASPHALT MEMBRANES ARE THERE?

Currently, the market offers hot-applied ready-made asphalt membranes and cold-applied self-adherent membranes. There are 3 kinds of asphalt membranes, which vary according to the coating type:

  • No Crack Aluminum-coated Membranes (non-walkable)
  • Geotextile Coated Membranes (walkable)
  • Normal aluminum-free membranes (for undercourse, not exposed use)

The coating function is to protect the asphalt layer from weathering and, in some cases, to allow foot traffic. The asphalt membrane coating type will vary according to its use. Different types of coating include:

  • NO CRACK ALUMINUM: Coating suitable for waterproofing weather-exposed non-walkable surfaces.
    The NO CRACK Aluminum coating (flexible aluminum) increases the membrane mechanical stress strength. Besides, it prolongs the product lifespan and increases the waterproofing safety.
  • GEOTEXTILE: Coating suitable for waterproofing asphalt membranes subject to frequent foot traffic.
    The geotextile coating is made out of a polyester fiber mesh called "nonwoven fabric", the resins of which increase its mechanical properties and its adhesion to the asphalt layer. It also provides an excellent aesthetic finish. When waterproofing exposed surfaces, application of the membrane should be followed by a coating of Geotrans Paint.
  • HIGH-DENSITY POLYETHYLENE: Membrane coating used on surfaces not exposed to weather, such as undercourse or underslab surfaces, or to be used under metal roofs. In these cases, the surface polyethylene film works as an anti-adherent material. Under no circumstances should this membrane be used without a proper cover or exposed to direct weather action.

G. WHAT IS NO CRACK ALUMINUM?

No Crack aluminum is a technological innovation developed by Megaflex. It is an aluminum composite coating used as surface protection for asphalt membranes. No Crack Aluminum entails a substantial improvement in its kind, since it is stronger and more flexible than the traditional aluminum coating, thus improving the product durability and users’ safety.

No Crack coating protects asphalt membranes from UV rays while providing a suitable mechanical protection against the strains a membrane may suffer throughout its lifespan.

Advantages of No Crack Aluminum:

  • Higher flexibility and adaptability
  • Higher stretching capacity
  • Higher strength against bending stress
  • Higher waterproofing safety
  • Longer lifespan
  • Less maintenance needed
  • Better resistance against hail and adverse weather conditions
  • Better adaptability to wavy, irregular, deeply cracked, etc., surfaces
  • Withstands bending in every angle without breaking
  • Withstands strains arising from expansion of materials

H. WHAT IS GEOTEXTILE AND WHAT IS IT USED FOR?

Geotextile is a mesh of randomly woven polyester fibers (called “nonwoven fabric”) used as a coating or central core in walkable membranes. It has resins which enhance mechanic properties and its adhesion to the asphalt layer.
Geotextile provides asphalt membranes with optimal strength against foot traffic impact, punching, and abrasion. Besides, it provides an excellent aesthetic surface finish.
This type of coating gives asphalt membranes increased strength and durability, and protects them from sunshine, hail, foot traffic, bumps and structural movements.

Megaflex Membranes containing Geotextile include:

I. ¿Para qué sirven las membranas asfálticas sin aluminio?

The aluminum-free asphalt membranes, also known as “regular” membranes, are suitable for those cases in which they are not to be exposed to weather, but placed underneath another material (screed, concrete subbase, slab, wood, steel sheet, tile, earth, or clay). Always make sure these elements do not harm the membrane. This product is ideal for floors, terraces, roofs, slabs, basements, retaining walls, etc.
Megaflex aluminum-free membranes include:

J. WHAT IS AN ASPHALT WATERPROOFING SYSTEM MADE OF?

A proper waterproofing system is made of:

K. HOW CAN I APPLY AN ASPHALT MEMBRANE SYSTEM?

Follow these instructions to ensure an efficient and lasting waterproofing:

  1. PRIMING
    1. Apply the primer evenly over the entire surface to be waterproofed.
      This includes the priming of any protruding or neighboring elements, such as perimeter walls, chimneys, ventilation devices, etc.
      The drainage area must also be completely primed.
    2. Once priming is complete, allow the surface to dry and install the membrane.
      Touch the material to make sure it has properly dried, so as to avoid detachments or displacements.
      Then, make sure the surface is clean, so as to achieve perfect membrane adhesion.
      Use one of these products to prime the surface:
      - Fast-dry solvent-based Megaflex Asphalt Paint
      - Aqueous Megaflex Asphalt Emulsion

    Please note that the chosen priming material must be compatible with the substrate, i.e. it must not damage the surface you are about to waterproof (substrate).

  2. MEMBRANE INSTALLATION Install the asphalt membrane rolls at a temperature no less than 5 °C (41 ºF)
    1. Successively place the rolls on one another, from the bottom to the top, of the surface.
      To begin with, extend the first roll perpendicularly to the surface slope, so as to make sure it will fit perfectly.
    2. Heat the surface of the membrane to be weld (anti-adherent side) with a torch, making sure the polyethylene is completely molten, and the asphalt is only superficially molten, though not burned. Then, stick it onto the substrate, exerting a soft pressure so as to distribute the asphalt evenly over the entire contact zone. Allow it to exudate, or “bleed”, out of the borders of the sealing, smoothing the surface with a hot metal spoon, so that a continuous poreless finish is achieved.
      * As you apply the membrane, let the surface temperature rise to around 40 °C (104 ºF), taking care that the surface to be waterproofed remains undamaged.
    3. Place the second sheet next to the first one, overlapping over the sealing area. The overlap should match the slope and be no less than 8 cm (3.15 inches) wide. Proceed likewise with all the rolls. End-of-roll overlaps should be 15 cm (5.9 inches).
    4. Flash the perimeter walls, chimneys, ventilation elements, etc., by completely adhering the membrane to the wall surfaces, so as to achieve a smooth watertight integrity. In all cases, apply a double membrane surface, and round off of the angle between floor and walls.
    5. Finally, apply the waterproof protecting finish. If a Geotrans membrane was used, cover it completely with Geotrans Paint.
      If a No Crack Aluminum coating was used, apply Megaflex Asphalt Aluminized Paint on the sealed areas so as to protect the asphalt sealing exudation and provide an aesthetic surface finish.
    6. A watertightness test is recommended so as to verify the accuracy of the waterproofing. Cover the drains and flood the roof up to the top of the metal sheet.
    Control and keep checking this process permanently for 24-48 h.

L. IS IT NECESSARY TO HAVE THE MEMBRANE FULLY ADHERED?

In most cases, it is recommended to have the membrane fully adhered to the affected surface, since it will ensure an increased resistance and a proper waterproofing.
A loose-laid installation entails a higher risk of membrane cracks. Furthermore, loose-laid installations do not allow for patching, and should there be any leak, the entire membrane would have to be replaced.
In particular cases, where the surface shows some considerable structural movements, a semi-adhered system is recommended, allowing the membrane to accompany such movements (seeMegaflex installation manual). In all cases, it is advisable to follow IRAM guidelines #12627 (“Installation guidelines for pre-manufactured asphalt membranes”).

M. HOW SHOULD I TRANSPORT AND STOW THE MEMBRANES?

Store the products in covered and weather-protected areas, at temperatures not below 5 °C nor higher than 40 °C (41–104 F).
Membrane rolls should be stowed in pyramids up to 5 rows high.

N. WHAT PRODUCT CAN I USE FOR PAINTING AN ALUMINIZED MEMBRANE?

Aluminized asphalt paint. It protects the exposed asphalt, especially in the exuding overlaps.

O. IS IT NECESSARY TO REMOVE AN OLD MEMBRANE IN ORDER TO INSTALL A NEW ONE?

It depends on the state of the old membrane. If it is loose or peeled off, removing it would be the best option. If it is properly adhered to the surface and presents no further trouble or leaks, it may be left in place so that the new membrane is applied on top.

P. HOW CAN I OBTAIN THE WRITTEN WARRANTY? WHAT ARE THE REQUIREMENTS?

The written warranty certificate accompanying the product specifies the validity conditions of it. Briefly, for the warranty to be valid, the products must be installed according to the recommendations outlined by Megaflex in the “Installation Manual” and also detailed in the IRAM guideline #12627 (“Installation guidelines for pre-manufactured asphalt membranes”).
Any claims regarding the product must be accompanied by the written warranty (which can be found inside the membrane roll), the sale ticket, and the product label containing the lot number.

Q. WHAT ARE LIQUID MEMBRANES?

Liquid membranes are acrylic waterproofing emulsions recommended for temporary leak repairs in not-waterproofed roofs. Once applied, the membrane forms an elastic waterproof coating, providing also an aesthetically nice surface finish. It may be used in combination with glass veil, geotextile, or reinforcing mat, which can be used as core for enhancing the waterproofing resistance.
Given their nature, these systems are recommended for temporary or provisional waterproofing in small to middle-scale roofs, but not for waterproofing large areas.

R. WHAT ARE THE DIFFERENCES BETWEEN ASPHALT AND LIQUID MEMBRANES?

There are several differences between asphalt and liquid membranes, the most important of which is the durability of the system. Below are the most outstanding differences:

Asphalt membranes

Liquid membranes

10-year written warranty

1-year average durability

Product supplied in rolls

Liquid product

Asphalt-based

Acrylic-based

Thicker waterproof layer

Thinner waterproof layer

More resistance and flexibility

Less resistance

Suitable for all surfaces

Suitable for small-scale flat roofs

Surface-independent

Works in combination with surface

Ready-made

In situ installation

Application with torch

Application with roller or brush

S. WHAT ARE LIQUID MEMBRANES USED FOR?

Liquid membranes are used for waterproofing small or medium-scale flat surfaces, patches and specific repairs. They are not suitable for large areas since they cannot withstand the waterproofing problems arising from their typical structural movements.

T. HOW CAN I INSTALL A LIQUID MEMBRANE?

The surface to be waterproofed must be clean (free from loose particles, fine dust, release agents, moss, etc.), dry and tough.
A roller or brush may be used.

  • Apply at least two coatings of undiluted product, which is the required amount to be used, depending on the application (see Yield).
  • Allow each coating to fully dry before applying the next (6–12 h depending on room temperature and humidity conditions).
  • On absorbent surfaces, first apply a priming coating by diluting EMULTRANS with up to 20% water.
  • To achieve a more efficient waterproofing, it is recommended to apply a first coating of Megaflex aqueous Asphalt Emulsion.
  • Total mass recommended for roof waterproofing ranges from 1 to 1.5kg/m2, depending on the surface characteristics.

The product may be applied with roller or brush once the surface has been properly cleaned and is free of dust or any other residue that may affect its installation.
For priming, a coating of asphalt emulsion may be applied.

U. IS A LIQUID MEMBRANE SUITABLE FOR WALKABLE ROOFS?

Yes, it is suitable for walkable roofs, provided some precautionary measures are taken. Since it is paint, it is very thin and will not be as resistant to foot traffic as a walkable membrane is.
Apply a first coating of asphalt emulsion as priming. Then, apply a first layer of liquid membrane. Before it dries, apply a polyamide mesh to enhance product resistance. Finally, you can apply two final coatings of undiluted finish.

V. MAY A LIQUID MEMBRANE BE APPLIED ON A METAL ROOF?

No, because given their nature, these types of roofing have many structural movements which cannot be provided for by this product, both in the sheet junctions and in between sheets and walls. An asphalt membrane is recommended for waterproofing these surfaces.

W. MAY A LIQUID MEMBRANE BE USED FOR UNDERSLAB WATERPROOFING?

No. Since the membrane is a liquid emulsion, it forms a very thin layer on the surface, which is liable to be broken when the cement screed is applied on top of it. In many cases, the waterproof membrane cracks, causing serious leak problems in the roofing.
To avoid this, an aluminum-free asphalt membrane is recommended.

X. MAY THE LIQUID MEMBRANE BE TINTED?

Yes, with any acrylic colorant until achieving the desired dye.

Y. WHAT MAY THE LIQUID MEMBRANE BE DILUTED WITH?

The liquid membrane may be diluted with water (up to 20% of water) for the first priming coating. Then, for proper sealing, two or three undiluted coatings should be applied.

Z. WHAT DOES THE 10-YEAR WRITTEN WARRANTY CONSIST OF?

The Megaflex Written Warranty certifies the durability of the waterproofing system for a minimum of 10 years. During that time span, Megaflex is responsible for any product failure included in the warranty conditions.
Megaflex warranty applies to the following No Crack coated asphalt membranes: MGX 400 NC, MGX 450 NC, A40C NC, MEGALUM 3mm NC, MEGALUM 4mm NC and GEOALUM 4mm NC.

AA. WHAT IS PRIMING AND WHAT IS IT FOR?

Asphalt priming is the application in cold of a liquid asphalt base in order for a membrane to be properly adhered to a surface, doubling its waterproofing durability. If the area is not primed, the membrane peels off from the surface easily, causing leak problems. This is one of the major causes of failure.
Priming can be made using solvent-based fast-dry Megaflex Asphalt Paint or aqueous Megaflex Asphalt Emulsion (base acuosa).

BB. WHAT ARE THE DIFFERENCES BETWEEN ASPHALT PAINT AND ASPHALT EMULSION?

The Megaflex Asphalt Paint is solvent-based, which allows it to dry fast (about 30-40 min per coating), while the Megaflex Asphalt Emulsion is aqueous-based, which means that drying may take several hours.
Before choosing a primer, please consider its compatibility with the surface to be waterproofed.

CC. WHAT PRODUCTS MAY BE USED AS A VAPOR BARRIER IN DOUBLE LEAF WALLS?

In double leaf walls, the Megaflex Asphalt Paint is used both as waterproofing membrane and vapor barrier. This paint may also be used in single leaf walls with applied coating.

DD. HOW CAN I DEAL WITH THE EXPANSION JOINTS OF A SCREED OR CONCRETE SUBBASE?

Expansion joints must be dealt with by applying a compressible material which allows for expansion of the surface. Hot-applied Megaflex oxidized asphalt blocks may be used.

Before applying Megaflex oxidized asphalt blocks, prime the joints using Megaflex Asphalt Paint . Then, heat the asphalt in a boiler up to liquid state, and pour it onto the joints up to 5 mm below their top, avoiding spilling liquid above the surface level.

Another suitable product for this use is Megaflex Polyurethane, a cold-applied flexible polyurethane caulk.