Horizontal barrier in masonry - Effective sealing against moisture
Damp walls and a musty smell in the cellar or living area are not only unpleasant, but can also lead to considerable structural damage in the long term. The main cause is often rising damp. A horizontal barrier offers a proven solution here. In this content, you will learn all about the causes of damp walls, how a barrier layer works and how you can solve the problem yourself.
Table of contents
- Introduction
- Importance of masonry waterproofing
- What is rising damp?
- Why is the fight important?
- How the horizontal barrier works
- Types of horizontal barrier
- What to do with a damp wall?
- The Isofin method
- Costs and materials
- Safety instructions
- Articles and accessories
- Preparation and implementation
- The drying phase
- Special cases and FAQ
- Conclusion
Introduction to the horizontal barrier
A horizontal barrier is an essential component of structural waterproofing that prevents ground moisture from rising capillary in the masonry. Waterproofing is a fundamental measure to permanently prevent the penetration of water and moisture into the building. This process can lead to various types of moisture damage, such as mold growth, plaster flaking and salt efflorescence. Horizontal waterproofing is therefore essential in order to dry out masonry and ensure that the building is waterproofed. In the following, we will discuss the function and effect of the horizontal barrier and safety instructions for its application.
The importance of masonry waterproofing

The waterproofing of masonry is a key factor in maintaining the value and functionality of buildings. Without effective waterproofing, moisture can penetrate the masonry unhindered and cause considerable damage. The capillary effect ensures that water rises from the ground into the walls and thus contributes to moisture penetration of the masonry. This not only leads to visible problems such as mold growth and peeling plaster, but also significantly impairs the thermal insulation of the building.
Professional masonry waterproofing permanently protects the masonry from moisture and prevents harmful salts and moisture from accumulating inside the walls. This significantly reduces the risk of mold damage and other structural damage. At the same time, a dry wall contributes to a pleasant indoor climate and reduces energy costs, as dry walls have a better insulating effect. The service life of the entire building is considerably extended by professional waterproofing, as the building fabric remains protected from harmful influences. All in all, masonry waterproofing is an indispensable part of any building waterproofing and should be given top priority in both new and renovated buildings.

What is rising damp and how does it occur?
Rising damp is a physical phenomenon in which moisture is transported upwards through capillary structures. This effect is caused by capillary action: the fine pores act like tiny tubes in which moisture can rise against the force of gravity.
Everyone knows the principle from everyday life: a sponge absorbs moisture, a blotting paper draws ink into itself. Exactly this mechanism also takes place when moisture from the ground penetrates the structure via the foundation.
Older buildings, especially those built before 1970, often lack a functioning horizontal barrier. In an old building, this can lead to visible mold growth and crumbling plaster. Barrier layers are prescribed as approved components in new buildings to protect the walls from rising damp, while they are often missing or damaged in old buildings. But even in newer buildings, the existing barrier layer can become damaged over the years.
Why is combating rising damp so important?

Damp walls are more than just an aesthetic problem. Continuous moisture penetration can damage not only individual walls, but the entire masonry and impair its stability and function. Continuous moisture penetration can lead to serious damage:
- Mold growth on the wall: Moisture provides ideal conditions for mold, which not only smell unpleasant but can also be harmful to health.
- Salt efflorescence and saltpetre: Moisture transports salts from the soil. During evaporation, these salts crystallize on the surface and leave behind the familiar white spots.
- Destruction of the mortar: The rising damp continuously dissolves lime from the masonry mortar, causing it to lose its binding strength.
- Thermal insulation loss: Damp constructions conduct heat significantly better than dry ones, which leads to higher heating costs. Even small amounts of moisture can significantly impair the thermal insulation capacity.
- Frost damage: In winter, the contained moisture can freeze and lead to cracks due to volume expansion.

Functionality and effect of the horizontal barrier
The horizontal barrier works by forming a barrier in the masonry that prevents the capillary absorption of moisture from the soil. This is achieved by silicification of the masonry, which forms a water-impermeable capillary barrier. The horizontal barrier can be applied using various methods, such as the injection method or the masonry sawing method. The choice of method depends on the type of masonry and the severity of the moisture damage. It is important that the horizontal barrier is applied correctly in order to achieve an optimum effect.
Types of horizontal and vertical barriers
There are various types of horizontal barrier, each of which is suitable for different areas of application. The content overview shows the most common methods:
- Injection system: Special water-repellent agents are injected via drilled holes. A special liquid injection can be used to ensure an effective moisture barrier. This method is particularly effective where there is a high level of moisture penetration.
- Wall replacement method: This method is used for severely damaged walls.
- Wall sawing method: The construction is cut horizontally and a barrier layer is inserted.
- Drill core method: Drill cores are taken and the resulting cavities are filled with water-repellent materials.
- Chrome steel sheet process: Thin chrome steel sheets are hammered into the construction.
- Electroosmosis: Electric fields are used to prevent moisture from rising.
- Silicification: Silicifying substances are used which harden in the pores and form a barrier.
The selection and professional application of suitable products is crucial for an effective horizontal barrier, as this is the only way to achieve a permanent and effective moisture barrier.
In addition to the horizontal barrier, a vertical barrier may also be necessary in some cases, especially in the case of lateral water pressure. The combination of horizontal and vertical barriers offers optimum protection.
What to do if the wall is damp? The solution with a seal of quality
A horizontal barrier forms a water-repellent barrier that prevents moisture from rising from the ground. Our products bear the quality seal for tested effectiveness and durability.
In new buildings, barriers are usually installed directly during the construction phase. In the case of old buildings or damaged layers, a barrier must be installed retrospectively.
The Isofin method: Effective solution with a seal of quality

Isofin is a special water repellent that does not seal the pores, but makes their surfaces water-repellent. This prevents moisture from penetrating through the pores of the building material into the masonry. This has the advantage that the construction can continue to "breathe" - water vapor can diffuse through the treated zone without any problems.
To the calculatorThe special advantages of Isofin:
- No clogging of the pores: Unlike silicification, Isofin does not clog the pores.
- Restore natural thermal insulation: After treatment, the pores fill with air again instead of moisture.
- Simple application: The application only requires a drill, Isofin products and some mortar.
- Long-lasting effect: The hydrophobic effect lasts for 20 years and beyond.
- Short delivery time: Our products are usually delivered to you within 1-3 working days.
How to create a horizontal barrier with Isofin yourself - instructions

The independent creation of a horizontal barrier with Isofin (injection fluid specially developed for sealing masonry) is an effective way of permanently protecting masonry against moisture. In addition to the Isofin product, you only need a drill, suitable masonry drill bits (approx. 12 mm) and a measuring tape. Start by thoroughly cleaning the masonry and removing all loose components so that the injection fluid can work optimally.
Then drill the boreholes at a distance of 25 cm along the desired barrier layer (halve the distances for concrete, please refer to the Isofin manual for further information). Now fill the prepared drill holes with the Isofin injection liquid. Ensure that the correct amount of liquid is applied in accordance with the enclosed brief instructions (varies with different wall thicknesses) in order to create a complete barrier against moisture.
Now allow the masonry to dry out. The process can vary greatly depending on the degree of moisture penetration. After drying out, carefully close the drill holes with simple mortar. Allow the masonry to dry sufficiently before carrying out further measures such as plastering or painting.
Please note that the professional execution of the work is crucial for the success of the waterproofing. If you are unsure about the application or the assessment of the masonry, call our expert Hendrik Flügge. This will ensure that your masonry is optimally protected against moisture and that no problems arise in the long term due to moisture penetration or mold growth.
How to create a horizontal barrier with Isofin yourself - instructions


Creating a horizontal barrier with Isofin is relatively simple and can be carried out without any special prior knowledge. Our detailed instructions will guide you through the process:
- Drill holes: Drill holes with a diameter of 10-12 mm into the masonry to be treated at a distance of 25 cm. The holes should be drilled diagonally downwards at a 45 degree angle.
- Inject Isofin: Insert the Isofin products into the drill holes. The construction removes the product automatically. The quantity required depends on the cross-section.
- Seal the drill holes: After the products have run out, remove the empty bottles.
- Drying phase: Allow sufficient time for drying and then seal the holes with waterproof mortar.
Would you like to know how much material you need for your masonry waterproofing?
With our Isofin calculator, you can quickly and easily calculate how many bottles of Isofin you need for your horizontal barrier. Simply enter the dimensions of your walls to be treated and you will immediately receive an exact material calculation.
To the calculatorCosts and materials
The cost of a horizontal barrier can vary depending on the method and the materials used. In general, the cost is around 100 euros per running meter. The materials required include:
- Isofin products: The central means of sealing.
- Drill with 12mm masonry drill: For pre-drilling the holes for the Isofin bottles.
- Borehole filling mortar: For sealing the boreholes after injection.
- Measuring tape: For measuring the distances between the drill holes (brief instructions are enclosed with your order).
The current delivery time: The product Isofin is ready for shipment the next day.
For larger orders of approx. 500 bottles or more, you are welcome to request an individual offer.
All products bear our quality seal and have a guaranteed fast delivery time of just a few working days
Preparation and implementation with detailed content
The preparation and implementation of the horizontal barrier is incredibly simple. Here is the content of the basic steps:
- Cleaning and drying: The construction must be cleaned before use.
- Drill holes: Drill holes 25 cm apart in the structure to be treated. Make sure you drill the holes in the right place to ensure effective sealing.
- Injecting the agent: Insert the Isofin product into the drill holes.
- Drying phase: Give the construction sufficient time to dry.
- Sealing the drill holes: After the agent has completely penetrated and the wall has dried, seal the drill holes.
The drying phase: What to consider after construction
Patience is required after the horizontal barrier has been created. The content of this phase is crucial for success:
- Ensure good ventilation: the better the air exchange, the faster the construction dries. This is particularly important to shorten the drying time.
- Use a fan if necessary: A fan can shorten the drying time.
- Wait with the plastering: Only when the construction is completely dry should further measures follow.
- Pay attention to evaporation aids: Drying appliances can lower the humidity.
Special cases and frequently asked questions about the content
Yes, Isofin is also ideal for constructions made of hollow blocks. It can also be used effectively in other masonry structures. With these materials, the products may run dry more quickly. However, this does not affect the effectiveness.
For poured concrete walls, the drill hole spacing should be halved to 12.5 cm, as concrete has finer pores. Make sure to drill the holes at the correct height to achieve the best effect. In contrast to silicification, breathability is retained.
The drying time depends on how long and how intensively the construction has been soaked. As a rule, a clear improvement can be observed after a few months. This is a normal process and does not indicate a lack of effect.
Yes, in many cases a combination of horizontal barrier and surface waterproofing makes sense, especially if there is a high lateral moisture load.
Conclusion: An investment with a seal of quality
Creating a horizontal barrier is a sustainable solution against rising damp and an important measure to protect your building fabric. A positive evaluation of our products by customers confirms the effectiveness and quality of our solutions. We ask every customer to leave a review of our products after purchase. All reviews are published after verification to ensure maximum transparency and trust for future customers. The Isofin system provides you with a proven, easy-to-use method.
Remember: The costs for a horizontal barrier are significantly lower than the costs that can arise from long-term moisture damage. The short delivery time allows you to start your project quickly.
Would you like to know how much material you need?
With our Isofin calculator, you can quickly and easily calculate how many products you need for your horizontal barrier. Simply enter the dimensions of your walls to be treated and you will immediately receive an exact material calculation.
To the calculatorSummary of the horizontal barrier in masonry
Overall, the horizontal barrier is an important component of structural waterproofing that prevents soil moisture from rising capillary in the masonry. Correct application of the horizontal barrier can dry out the masonry and ensure that the building is waterproofed. The use of horizontal barriers can prevent various types of moisture damage and extend the service life of the masonry.
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