Training and library

Why does a porcelain tile appear clean after removal with PEGOLAND DOS, PEGOLAND DOS PLUS, PEGOLAND FLEX or PEGOLAND SUPERFLEX?

This is normal. Porcelain tiles have very low absorption, so chemical adhesion (not mechanical) is used. C2 PEGOLAND range contains high-resin content for this purpose.
The tile appears clean because the adhesive doesn’t penetrate it, it bonds chemically on the surface, ensuring a strong hold despite the clean appearance.
 

Why not apply mortar below 5°C or above 35°C?

Below 5°C:

• Water in the mortar may freeze, disrupting hydration and causing poor setting, cracks, and weak mortar. 
• Cement setting slows, reducing final strength.

Above 35°C:

• Water evaporates too quickly, leading to insufficient hydration, weak bonding, and cracking.

Best practices:

• Work early in the morning or late afternoon on hot days. 
• Shade sun-exposed facades with awnings.
   

Why use smaller panels for large ceramic tiles?

Ceramic and substrate materials expand and contract differently with temperature changes. To accommodate this, expansion joints filled with MORCEMCOLOR grout are used.
For large surfaces or exterior walls, larger joints filled with elastic sealants like PUMALASTIC are needed. The larger the tile, the fewer the joints—so more expansion joints are required to prevent cracking.
 

Difference between Morcemsec and Morcemdur mortars

The main difference lies in their classification under EN 998-1:

• Morcemsec: General-purpose (GP) or colored (CR) rendering mortar 
• Morcemdur: One-coat (OC) mortar with higher performance requirements

Morcemdur must pass additional tests:

• Adhesion after freeze-thaw cycles 
• Water permeability after freeze-thaw cycles 

These tests demonstrate Morcemdur’s superior durability, achieved through added resins, lightweight aggregates, and fiber reinforcement.

Advantages of industrial mortar vs. traditional site-mixed mortar

Traditional mortar is mixed on-site from individual components (cement, sand, etc.).
Industrial mortar is pre-mixed in a factory, either as dry mix (to be mixed with water) or wet mix (ready to apply).
According to EN 998-1, the advantages of industrial mortar include:

• Product consistency: Factory dosing ensures precise proportions, eliminating human error. 
• Raw material control: Internal lab testing ensures consistent quality. 
• Labor savings: Fewer workers are needed since mixing is simplified. 
• Faster execution: Especially when using projection machines. 
• Simplified logistics: One supplier instead of many, reducing delays and administrative complexity.
   

Why must rainwater resistant plaster be at least 1 cm thick?

To waterproof a facade using cement-based mortar, the mortar must contain water-repellent additives to reduce capillary water absorption. According to UNE-EN 998-1, mortars are classified as:

W0: No specified values 

W1: ≤ 0.40 kg/m²·min^0.5 

W2: ≤ 0.20 kg/m²·min^0.5 

For interior or lightly exposed walls, W0 and W1 may suffice.
For facades and exterior walls, W2 mortars are recommended for rainwater resistance. To achieve this, a minimum thickness of 1 cm is required to ensure the necessary concentration of water-repellent additives per square meter.

Why use a primer on smooth concrete?

Smooth concrete has a vitrified, low-porosity surface that prevents proper adhesion of cement-based mortars, which rely on mechanical bonding.
Therefore, a bonding primer is essential. It typically contains resins for chemical adhesion and mineral fillers to increase surface roughness, ensuring proper bonding of coatings on non-absorbent surfaces like smooth concrete.
 

What is the declaration of performance (DoP)?

The Declaration of Performance (DoP) is a legal document that must be publicly available. It identifies the product, its intended use, and its declared performance—such as for mortar—if the product is covered by a harmonized European standard (hEN) or a European Technical Assessment (ETA).
These declarations are usually validated by an independent body, though some products only require internal quality control documentation per European standards.
By issuing a DoP, the manufacturer assumes full responsibility for the product’s compliance with the declared performance.
 

Why is passivation important?

Passivation is the corrosion protection provided by concrete to steel reinforcement due to its alkalinity. However, this alkalinity decreases over time due to carbonation, a reaction between atmospheric CO₂ and concrete. Carbonation accelerates in porous concrete or when the protective concrete cover is less than 2 cm.
Carbonated concrete offers no protection, and in the presence of moisture, the steel reinforcement rusts. Rust expands, causing the concrete to crack and detach.

Why are gypsum and cement incompatible?

Gypsum and cement are often considered "false friends": they seem compatible at first but become incompatible over time.
Gypsum, is a component of Portland cement. When mixed with water, it forms ettringite, which gives the cement paste its plasticity and controls setting time and hardness development.
Primary ettringite forms during the first hours of hydration and up to about 28 days.
Secondary ettringite, with the same chemical composition, forms after the cement has fully hardened (post-28 days).
A common scenario is applying cement-based mortar over gypsum plaster (or vice versa). When water reactivates the cement in contact with gypsum, secondary ettringite forms, causing expansion due to chemical incompatibility. This leads to the formation of expansive salts and ultimately the disintegration of the mortar.

Efflorescence: what is it, how to prevent and treat it?

One of the most common issues affecting facades is efflorescence. These are irregular white stains that appear on surfaces exposed to moisture. When the surface dries and the water evaporates, some of the soluble salts present in the water crystallize, causing efflorescence to appear.
The main causes of this problem are rainfall and excessive humidity. Therefore, protecting surfaces from these factors is essential to prevent and treat efflorescence stains.

Causes and types of efflorescence. 
Efflorescence, also known as saltpeter or alkalinity, is not only an aesthetic issue but can also pose a risk to the substrate it affects, as it can cause significant deterioration. This condition typically appears on concrete, brick, and stone surfaces. Key contributing factors include:

• Highly porous construction materials containing soluble salts 
• Weather conditions such as rain and low temperatures 
• Moisture from capillary rise or condensation 

There are two types of efflorescence:

• Primary efflorescence: Occurs on newly completed construction sites due to moisture. Although usually unavoidable, it tends to disappear shortly after without leaving a trace. 
• Secondary efflorescence: Appears in older buildings due to poor construction or unsuitable materials. It can also result from high porosity or moisture, as previously mentioned.

How to prevent and treat efflorescence.
This troublesome condition can be prevented in several ways. For new constructions, special care must be taken in selecting appropriate materials. Avoid using hard water and highly alkaline mortars. It’s also crucial to respect the drying times of each material used.
For existing surfaces, controlling moisture is essential. As noted, both condensation and capillary rise can cause efflorescence. Each must be addressed differently:

• For condensation, apply a thermal insulation system. 
• For capillary rise, structural improvements are needed, as the moisture originates from the ground.

If efflorescence stains have already appeared, the main step is to clean the surface and then apply a new protective layer. The simplest method is using pressurized water and a brush, though sometimes a specialized cleaner is required. After cleaning, allow the surface to dry completely to prevent recurrence.
To complete the process and prevent future stains, it’s advisable to apply an additional protective product like ANTISALMOR, a water-based additive designed to eliminate and prevent efflorescence caused by saltpeter on common construction surfaces such as mortar, concrete, brick, reinforced concrete, and natural stone. It penetrates deeply and dissolves salt effectively, preventing crystallization on the treated surface. It is transparent, colorless, and capable of binding loose or poorly adhering particles.