Solving Rising Damp with Damp Injection: Step-by-Step Application

Solving Rising Damp with Damp Injection: Step-by-Step Application

Rising damp is one of the most common and most damaging problems in buildings. Moisture at ground level rises within the wall by capillary movement, causing paint to flake, mould to form and structural damage. Damp injection is the most effective method offering a permanent solution to this problem. In this guide we look in detail at what damp injection is, when it is needed and how it is applied step by step.

What Is Damp Injection?

Damp injection is the process of injecting special chemical solutions, by pressure or by gravity, through holes drilled at the base of the wall. The injected material fills the pores within the wall to form a waterproof barrier. This barrier prevents moisture in the ground from rising by capillary action and is also known as a damp-proofing injection.

Traditional methods required digging out the base of the wall or mechanically inserting a horizontal insulation layer. Because damp injection can be applied with minimal intervention to the structure, it provides a great advantage in terms of both cost and time. Especially in existing buildings, the fact that it can be applied without cutting the wall or dismantling the foundation makes this method indispensable.

When Is Damp Injection Needed?

The symptoms of rising damp usually start on the ground floor and, if neglected, can spread to the upper floors. If you observe one or more of the following, a rising damp injection application may be needed:

• Blistering or flaking paint at the base of walls: the clearest sign that moisture has reached the wall surface.
• Salt efflorescence on plaster: white or grey salt deposits show that the moisture is carrying minerals.
• Mould and fungus growth: appears as dark stains, especially on interior walls with poor ventilation.
• A damp zone up to 50-120 cm above the floor: the typical range that capillary rise reaches.
• A persistent feeling of damp in basements and on ground floors: a high ambient humidity causes condensation on the walls.

Once these symptoms are identified, it is important to diagnose the source of the problem correctly. Different causes such as leakage, condensation or a plumbing leak can produce similar signs. For a definitive diagnosis, a professional moisture measurement is recommended. By filling in our quote request form, you can get a free preliminary assessment from our expert team.

How Is Damp Injection Applied?

The damp injection application consists of four basic stages. Carrying out each stage correctly is critical to a long-lasting, permanent result.

Step 1: Drilling

Holes are drilled 5-10 cm above the base of the wall, at an angle of about 30 degrees to the ground. The distance between holes is usually set at 10-12 cm. The hole diameter should be 12-14 mm, and the depth about two thirds of the wall thickness. If the application is to be carried out from a single side, the hole depth is adjusted according to the wall thickness.

Step 2: Injecting

The prepared injection solution is injected into the holes by a pressurised or non-pressurised method. In pressurised injection, the solution penetrates the pores more quickly and evenly. In the non-pressurised (gravity) method, the solution spreads into the pores under its own weight. The appropriate method should be chosen according to the wall structure and moisture level.

Step 3: Waiting

After injection, a waiting period is needed for the solution to react within the wall and form the waterproof barrier. This period varies between 24 and 72 hours depending on the wall thickness, moisture content and ambient temperature. Ventilating the wall during the waiting period speeds up the drying process.

Step 4: Plastering

Once the barrier has formed, the old plaster in the affected areas of the wall is removed and re-coated with a special damp-resistant plaster. At this stage, using a restoration plaster resistant to the effects of moisture and salt, rather than standard plaster, is of great importance.

Damp Injection with DampStop Concentrate

Dryvatec DampStop Concentrate is a high-performance DampStop injection product developed for the rising damp problem. Thanks to its silane and siloxane-based concentrated formula, it is used diluted with water and forms a permanent hydrophobic barrier in the wall pores.

The key advantages of DampStop Concentrate:

• Concentrated formula: 1 part product is used mixed with 19 parts water. This lowers transport and storage costs and makes it easy to prepare on site.
• Deep penetration: thanks to its low viscosity, it penetrates deep into the pores of different building materials such as brick, stone and breeze block.
• Long-lasting protection: when applied correctly, it maintains its effect for decades.
• Environmentally friendly: it contains no solvents and emits no harmful gases after application.
• Wide compatibility: it can be used safely on all types of masonry walls, in historic buildings and in modern structures.

In different ground conditions or in structures under the effect of pressurised water, a combined application with acrylic gel injection material can be carried out. Acrylic gel expands on contact with water to fill cracks and voids, providing an additional insulation layer.

Plastering After Injection: HydroFix Application

Once the damp injection is complete, re-plastering the wall is at least as important as the injection for the integrity of the system. Standard cement or gypsum plaster is not resistant to the effects of moisture and salt and can deteriorate again quickly.

Dryvatec HydroFix Two-Component Damp-Proofing Plaster is specially formulated for use after damp injection. The advantages a HydroFix application provides:

• Salt barrier: it prevents the salts within the wall from emerging at the plaster surface, so no efflorescence forms.
• Breathable structure: thanks to its water-vapour permeability, it allows the wall to dry out naturally, yet it does not let liquid water through.
• High adhesion: it provides excellent adhesion even to damp surfaces.
• Easy application: it is prepared by mixing the two components and applied with traditional plastering techniques.

HydroFix is the finishing complement to the horizontal barrier created by injection. Using these two products together forms a complete protection system against rising damp.

Frequently Asked Questions

How long does the wall take to dry after damp injection?

How long the wall takes to dry out completely depends on the wall thickness and the existing moisture content. In general, the wall is observed to dry noticeably 4 to 12 weeks after injection. On thick stone walls this period can extend to as long as 6 months. Barrier formation itself is complete within 24-72 hours.

How many years does damp injection last?

With quality material and correct application, damp injection can maintain its effect for the lifetime of the building. Silane-siloxane-based products such as DampStop Concentrate bond chemically to the wall material, so they do not wear away or wash out over time. The application is expected to last at least 20-30 years.

Can you carry out damp injection yourself?

In simple, single-storey buildings, it is possible to carry out the application yourself with the right material and equipment. However, correct diagnosis and determining the appropriate hole spacing and depth require expertise. Incorrect application can lead to both wasted material and the problem persisting. Professional application is recommended especially in historic buildings and over large areas.

Can damp injection be applied to any wall?

Damp injection is applied effectively on porous building materials such as brick, breeze block, natural stone and mortared masonry walls. On reinforced-concrete shear walls, different insulation methods should be preferred. The suitability of the wall structure is determined by an assessment carried out before application.

What does the cost of damp injection depend on?

The cost varies according to the wall length, wall thickness, moisture level and the amount of material to be used. Concentrated-formula products give a more economical result per square metre than ready-mixed solutions. To get pricing specific to your project, you can fill in our quote request form.

Conclusion

Rising damp is a problem that seriously threatens the health of a building when neglected. Damp injection offers the most permanent and least intrusive solution to this problem. The chemical barrier created with DampStop Concentrate, and the system completed with HydroFix plaster, protect your building from damp for many years.

If you want to solve the damp problem in your building permanently, fill in our quote request form. Our expert team will determine the right solution for your building and get back to you as soon as possible.