Rising Damp Treatment: What Works on a Solid Wall

In practice, rising damp treatment begins at the base of the wall, and it begins with the cause. So work out where the water comes from, then give the masonry the months it needs to dry. Nothing useful here happens in a fortnight.

Ground water travels upwards through the pores of stone, brick and mortar. Nothing pushes it up there, the material itself draws it, and rising damp treatment has to reckon with that.

What rising damp treatment has to work against

Brick, stone and lime mortar are riddled with microscopic channels. The finer the channel, the higher the water climbs. So an old wall with fine lime pointing often shows a tide mark a metre above the floor. Physicists call the effect capillary action, and it works in masonry as it works in a paper towel.

At the surface the water evaporates and the dissolved salts stay behind. They crystallise, they swell, and they break the render apart from within. Our article ATE: electromagnetic anti-damp device for damp walls and rising damp follows the whole journey from the footings upwards.

Salt makes rising damp treatment slower, because the crystals drink moisture straight out of the air. So a heavily salted wall still feels damp long after the rise has eased.

Which cause you are actually looking at

Three faults leave much the same mark. Rain driving through the outside face, a leak from a pipe or a gutter, a room that never gets a change of air. Together they remain more common than capillary damp, so rule them out first. Our article Rising Damp: Signs, Causes and Solutions lists the tell-tale signs of each one.

Capillary damp has its own signature. The mark sits low, within roughly a metre of the floor. It climbs in winter and falls back in summer. Then it brings salt efflorescence, damaged render and flaking paint along the skirting board. The first step in rising damp treatment is to measure that height, then pencil the date beside it.

Which methods count as rising damp treatment

Resin injection means drilling the wall every ten centimetres or so and pumping in a cream meant to form a barrier. It is invasive work, and it needs the whole length of the wall to be reachable.

Drainage and a fresh outside render mean excavation and scaffolding, heavy going on a house that is already lived in. Neither route is wrong, yet both put a building site in the middle of your year.

In practice, an electronic unit asks for two wall plugs. The ATE is an electromagnetic polarity inverter that sends very low frequency electrical pulses through the masonry, hour after hour. Its design principle comes from electro-osmosis. The pulses act on the electrical charges where the water meets the wall of the pore. So they work against the climb and favour the return of the water towards the footings.

That is the design principle, and we claim nothing beyond it. The unit pulls nothing out and warms nothing, so the drying happens by evaporation, at the pace of the seasons. Resin injection cost: is there an alternative? covers this route in more detail, while Damp Wall Treatment: Which Solution Should You Choose? compares the ATE and ATG ranges.

Choosing the model that covers your walls

Each unit works over a radius, measured from the point where you fix it. So measure the walls you want to treat, then pick the model whose radius covers them from a central position.

Model	Range	Price
ATE LC15	7.5 m radius, 15 m across	€1,290
ATE LC30	15 m radius, 30 m across	€1,590
ATE MAX	30 m radius, 60 m across	€1,990

Every unit draws 0.75 W on a 12 V supply and measures 322 x 232 x 32 mm. Each one carries a 10-year manufacturer warranty. All three are made in France, and delivery costs nothing. The ATG follows the same design principle with no mains supply, which suits a wall with no socket within reach.

Fitting the unit yourself

Fix it to a load-bearing wall or a partition wall, between 30 cm and 1 m above the floor. Aim for the centre of the area to treat. Two wall plugs and a socket, less than an hour, no tradesman.

Never fix it to plasterboard and never to insulation. The back of the unit has to touch the masonry. Keep 1.50 m between the unit and any other electrical equipment.

If the bottom of the wall carries a waterproof cement render, cut that render back over ten centimetres or so. Then the water reaches the air and evaporates, instead of sitting trapped behind a sealed skin.

What to do while rising damp treatment runs its course

First, take off whatever is loose: flaking paint, damaged render, any coating that traps vapour. In practice, rising damp treatment works best on a wall left bare, with air moving across it.

Leave the finish until the end. A lime render and a vapour-open paint let the masonry carry on drying, whereas a plastic emulsion seals the water inside. Our guide ATG Geostop: the standalone unit that installs without an electrician compares the options honestly.

White bloom keeps appearing for a while. Brush it off dry, then brush it off again next month, because that cycle is normal during rising damp treatment. Our article ATE or ATG: which Humidistop device to choose against damp walls explains where those crystals come from.

Frequently asked questions

How do I know the damp is rising rather than something else?

Rising damp stays low, within about a metre of the floor, and it comes with salt efflorescence and crumbling plaster. A patch that sits high on the wall and spreads after rain points to water coming in from outside.

How long does rising damp treatment take to show results?

Visible results come between 18 and 24 months, because a wall dries by evaporation and nothing hurries that along. A thick stone wall sits at the slower end of that range.

Does an anti damp wall unit need an electrician?

No. The ATE plugs into an ordinary socket, draws 0.75 W and fixes to the wall with two plugs in under an hour.

Can the unit go on a partition wall?

Yes, provided that wall is masonry, load-bearing or a solid partition. It must never sit on plasterboard or on insulation.

Does rising damp treatment cover condensation as well?

No. A unit of this kind acts on water rising from the ground, so condensation and leaks need their own remedy.

Before you order

The unit treats rising damp and capillary damp, and nothing else. It does nothing for a leaking gutter, for driving rain, or for poor ventilation. Those three causes together remain more common than capillary damp, so rule them out first.

Rather than guess, send us two or three photos. One of the bottom of the wall, one of the room, one of the outside face. We read them and tell you which model fits, or tell you plainly that your problem lies elsewhere.

See the ATE and ATG models · free delivery, 10-year warranty, made in France