Damp walls, a musty smell or crumbling plaster? This often indicates a fundamental problem in the masonry: a missing or defective barrier layer. In old buildings, the so-called horizontal barrier is often completely missing - with serious consequences.
In this guide you will find out:
- What a horizontal barrier is
- How it works
- When and why it is missing
- What methods are available for the subsequent barrier layer
- Why Isofin® offers a simple DIY solution (only for capillary moisture)
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Isofin®: The simple DIY horizontal barrier for retrofitting
Isofin® is a specially developed injection agent for the subsequent barrier layer in masonry. It forms a water-repellent zone in the wall and permanently blocks the capillary rise of moisture.
Advantages at a glance:
- Simple application with bottle system
- No special tools required
- Suitable for brick, sand-lime brick, aerated concrete and much more.
- 20-year effectiveness guarantee
Important note:
Isofin® is only effective against capillary moisture. Other sealing systems are required for pressing water. Contact our experts for a free consultation.
How easy it is to use
1. measure & drill holes
Drill holes with a diameter of 12 mm at an angle of 45° into the affected wall at intervals of 25 cm.
2. use Isofin
Screw the Isofin® bottles into the adapters. Simple, pressureless application - Isofin® is evenly distributed in the masonry.
3. enjoy dry walls
Results are visible after a few weeks. Then seal the drill holes with simple mortar.
What does the renovation really cost?
With our calculator you can find out immediately:
- 🔍 How much Isofin® you need
- 💶 What your waterproofing costs
- 📉 How much cheaper you drive compared to a specialist company
Save up to 70% - with guaranteed effect over 20 years!
Free Isofin® manual
You will find detailed step-by-step instructions for all applications in our comprehensive manual:
- Standard application with different wall thicknesses
- Special cases such as hollow blocks and natural stone
- Solutions for mixed masonry
- Troubleshooting and FAQ
- Material consumption tables
Stop moisture permanently now!
With Isofin® you can easily retrofit your horizontal barrier and tackle the cause of moisture directly at the root - safely, easily and with lasting effect.
Order Isofin® nowComparison of methods for subsequent horizontal barriers
| Procedure | Typical costs | DIY possible | Expenditure | Disadvantages & risks |
|---|---|---|---|---|
| Isofin injection (DIY) | from approx. 80 €/running meter | ✅ Yes + 20-year guarantee | Low | - |
| Injection process (specialist company) | 180-280 €/m² | ❌ No | Medium | Only by a specialist company |
| Wall replacement | 400-800 €/m² | ❌ No | Very high | Intervention in statics, expensive, complex |
| Wall sawing method | 350-650 €/m² | ❌ No | High | Static risk, dust-intensive |
| Drill core method | 200-350 €/m² | ❌ No | High | Expensive special device required |
| Chrome steel sheet | 200-300 €/m² | ❌ No | Very high | Not suitable for all wall types |
| Electroosmosis | from 190 €/m² | ❌ No | Low | Controversial effect, rarely works |
| External sealing | 1,000-1,500 €/rm | ❌ No | Very high | Does not work with rising damp |
If you have any questions about the various procedures or would like individual advice, please contact our experts:
What is a horizontal barrier in masonry?
The horizontal barrier is a horizontal barrier layer in the masonry that prevents the capillary rise of moisture from the ground. In new buildings, this barrier layer is installed directly above the floor slab - usually as a bitumen sheet or plastic film - and is anchored in DIN 18195 (waterproofing standard).
Why is the barrier layer in the masonry so often missing?
Especially in old buildings (built before 1970), either no barrier layer was installed or only simple materials such as roofing felt were used. These have deteriorated over time:
- Become porous
- Disintegrated or torn
- Destroyed by alterations or cracks
Without a functioning barrier layer, capillary moisture can rise unhindered and cause long-term damage to the entire masonry.
Without a horizontal barrier:
- Soaked plinth areas
- Mold stains & mildew
- Efflorescence and salt edges
- High heat loss & poorer indoor climate
How does a horizontal barrier work?
The horizontal barrier blocks the capillary action in the masonry. It interrupts the water column so that water can no longer rise upwards. The wall above the barrier remains dry.
In modern buildings, the horizontal barrier is installed directly during construction using plastic or bitumen membranes. These are laid on the floor slab or foundation before the walls are erected.
In existing buildings without a functioning barrier layer, installation is carried out using subsequent methods such as injections, masonry saws or other special techniques. These create a water-repellent barrier directly in the masonry.
When does a subsequent horizontal barrier make sense?
Damp walls
You observe damp spots in the lower wall area (up to approx. 1 m high) that do not come from outside or water pipes.
Mildew stains and mold
Dark stains, black spots or a musty smell are typical signs of a moisture problem.
Peeling plaster
The plaster is crumbling or flaking, especially in the plinth area. White efflorescence (salt edges) is visible.
Important note:
A subsequent horizontal barrier is only effective in the case of capillary moisture. Other waterproofing systems are required in the case of pressing water (e.g. on slopes, defective drainage, standing groundwater). Our expert will be happy to advise you - contact us.
Do you have any questions?
Get a free expert opinion!
For an optimal assessment, simply send us photos of your damage or give us a call - our expert Hendrik Flügge will analyze the situation free of charge and recommend the best solution for you.
Availability by telephone:
Mon.-Fri.: 9.00 - 20.00 h
Sat. & Sun.: 10.00 - 15.00 h
Isofin®
Freimuth Building Protection GmbH
TecCenter 1
31162 Bad Salzdetfurth
Germany/Germany
Email: [email protected]
Frequently asked questions
We have compiled the most important questions about Isofin® and horizontal barriers for you.
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