Damp Proofing for Osmosis

The MacLennan osmosis system repels rising moisture molecules back into ground to combat any risk of rising damp.

Chemical Free Damp Proofing

When moisture in soil and masonry tries to achieve equilibrium, it is known commonly as Rising Damp. Found naturally in most masonry structures, the equilibrium will be evident in its many forms, such as temperature (where heat spreads from hot to cold), in water (where dampness invades a dry area), and electricity (where a positive charge flows to the negative). All are naturally occurring.

An electrical potential (Zeta Potential) is created by moisture from the earth, rising through the pores of the wall structure. Damaging ground salts carried by the water molecules travel from the positive (earth) to the negative (the wall structure) due to this potential.


Electro Up
Electro Down


The absence of an effective damp-course or bridging of the damp-course is the most common cause of Rising Damp.

Excess mortar can often fall into the cavity during bricklaying that can then lead to the mortar sticking to the wall ties, which will then lead to a ‘moisture bridge‘ which will allow moisture to creep directly from damp masonry. “Rendered” finishes can, in some cases, also cause a moisture “bridge” if applied over the damp course area of the wall, thus enabling moisture to creep up the wall.

With the wetting/drying cycle caused by fluctuation of moisture levels and constant expanding and contraction of the salts in the masonry it will perpetuate the breakdown and deterioration of the plaster, brick/stonework and mortar, floor bearers, joists, perimeter timber framing, and timber trims.

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MacLennan provide a simple and unobtrusive solution to the problem of Rising Damp

Using the MacLennan osmosis system, we are able to repel the rising moisture molecules harmlessly back down the walls and into the ground. The system is delivered through a series of titanium anodes inserted just above ground level into the brick work, and introduces a very small but perfectly safe electric current. The walls will remain dry and totally free from rising damp, as long as the positive charge is maintained.

Installation of the MacLennan osmosis system is quick and neat.

The installation is carried out by a series of small holes being drilled in the outside masonry (just above ground level); tiny anodes are inserted into the holes, and then linked by a special connecting wire which is ‘pointed’ into the wall. The finished result is virtually invisible and disruption is minimal.


  • Osmosis System Benefits

    • Guards permanently against the dangers of rising damp.
    • Properties of any age or structure can be protected.
    • Installation is simple with minimal disturbance to building structure.
    • Effective immediately.
    • Virtually indestructible (self healing).
    • A monitoring system can be fitted for added peace of mind.
    • 20 year fully insurance backed Guarantee.
  • Why Use the MacLennan Osmosis System?

    1. The MacLennan Osmosis damp proofing system is controlled by a robust power unit which automatically adapts to the degree of moisture in the wall. The constant electrical voltage produced by the MacLennan-LSE osmosis power unit guarantees the optimal required drying process.
    2. The MacLennan osmosis anodes and connecting wire have a pure titanium coating which will resist chemical and physical attack and enables the system to be one of the most reliable solutions to the problem of Rising Damp.
    3. The Maclennan osmosis system is completed by earth rods installed into the ground enabling the small electrical voltage to ‘force’ the moisture down the wall and preventing damage to the structure.
  • Osmosis System Diagram

    Diagram showing initial switch on conditions. Total electrical conduction

    Electro Pulse

Why should I work with MacLennan?


We Design, supply and install. There's no split responsibility with MacLennan.


MacLennan live and breathe waterproofing, have a look at one of our free CPD seminars and find out!


MacLennan has the most comprehensive guarantees and insurances in the industry.

Safe Contractorx
Full 4th May 2010 06 22 42 Gpi Logo E1443710209909x
Safe 4 Sitex

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