What are the properties of a waterproof cement mortar?

Waterproofing products can be divided into: discontinuous sheets of asphalt type or modified plastics and continuous liquid membranes, which are distinguished by their basic composition into acrylic, bituminous, polyurethane, polyurea or cementitious type.

In this post, we will explain the properties of waterproof cement mortar and recommendations about Molins products.

Waterproofing cement mortar: What is it and its properties?

This very specific type of cement mortar is a waterproofing membrane whose base or main hardening component is cement.

This cement is accompanied by other products such as water repellents and resins, making it a waterproofing membrane with unique properties:

• It is fully compatible with masonry products and systems, along with any other type of subsequent finishing.
• They are impermeable to direct pressure and to negative pressure (if water comes through the support).
• They allow permanent immersion.
• It is not excessively difficult to obtain a certificate of potability, with a very simple application, impermeable to liquid water but permeable to vapour (breathable).

They stand out from other mortars for being resistant and durable products in different environments, both in interior and exterior floors and walls.

Waterproofing cement mortar for facades

The mortars for façades must be impermeable to rainwater, according to the standard for cement mortars(Standard EN 998-1), i.e. they must have a resistance to water absorption by capillary action with a nomenclature of W1 or W2. According to the Technical Building Code (CTE), systems with a high resistance to filtration will be those rendered with mortars with a water-repellent additive and applied in a minimum thickness of 15 mm.

At Molins we have the best products for façades, so we recommend our cement mortars such as PROPAM REVOC, lime mortars such as REVAT CAL ENFOSCADO, or even monolayers such as REVAT RASPADO.

Waterproofing mortar for terraces

On the other hand, waterproofing cement mortars for terraces and roofs are those which, when applied as if they were a continuous membrane, firstly manage to be watertight, and secondly, as they are located outdoors, they must be able to absorb certain expansion movements of the materials and bridge cracks.

They must therefore comply with the standard for waterproofing membranes under ceramics(EN 14891).

In this sense, at Molins we recommend our most widely used and highly valued flexible waterproofing mortar, the product Propam® Impe Flex.

You may be interested in: How to waterproof a terrace

When and how to apply waterproof mortars?

It should be noted that this type of mortar is compatible with any finishing system and, in addition, as it is very efficient in terms of quality/price, it should be the first option we have in mind, regardless of whether we want to waterproof with direct pressure or negative pressure.

Implementation is very simple:

1. We apply with a trowel or brush two coats of thick paint, 1 mm thick each coat, and sometimes, if we consider it appropriate, we even use two auxiliary products such as elastic strips adhered and embedded with the waterproofing at floor/wall junctions, expansion joints or sharp fissures.
2. For this purpose we use BETOTAPE SEAL, or the fibreglass mesh embedded in the waterproofing in the case of needing to reinforce the membrane in large areas or subject to large expansions(BETOFIBER GLASS).

Best waterproofing cement mortar: Molins Products

PROPAM® IMPE

Propam® Impe is the ideal product for waterproofing and protecting any type of tank or reservoir intended to contain drinking water, basements and lift shafts. It provides a completely waterproof coating, filling in all the voids and pores of the substrate, making it truly continuous. A thick layer version is available if we want to regularise the surface and waterproof at the same time(Propam Impe Thick Layer).

PROPAM® IMPE FLEX

Propam® Impe Flex mortar is formulated with cement, previously selected aggregates and waterproofing resins. It has the great advantage of waterproofing for and against hydrostatic pressure, it is permeable to water vapour, avoiding condensation, it is specific for waterproofing under ceramics, it bridges cracks. It is versatile for most waterproofing situations on site.

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