Dealing with damp issues

If any of these things are occurring, you've got damp problems:

• A musty smell in the house - this is an obvious sign of 'rising damp'.
• Paint and wallpaper may start to lift from the wall surface.
• Brown stains start to appear on the wall.
• Plaster becomes flaky and soft and starts to fall away.
• White powdery or crystalline substances form on surfaces, and timber skirting boards and floorboards start to rot.
• Outside the house, symptoms such as stains and powdery deposits or mortar starting to fall out from between bricks.

In this article you will know how to fix it permanently,..

What is rising damp?

Rising damp is the result of salt-containing groundwater rising up masonry walls by capillary action (i.e. the porous masonry draws moisture into it).

Building design usually allows for this natural action by putting a moisture barrier or 'damp course' between bricks or blocks just above ground. level to stop the water rising. However, if this has deteriorated due to age (or was never installed in the first place) or has been bridged by internal concrete floors, renders or external paths and earth levels, it won't work.

The moisture will continue to move up the wall and leach out of the surface, causing health problems for both you and your house. Timber homes can also suffer damp rising up brick chimneys and then affecting the surrounding timbers. If you try to hide the results of rising damp by covering walls with waterproof render or paneling, you'll only end up forcing moisture further up the walls. You need to fix the problem!

Falling damp

The moisture may also be coming from above or horizontally through your wall, this is known as 'falling damp'. It's usually caused by leaking or inadequate roof drainage. Overflowing gutters or leaking down-pipes spill water onto brick walls, making them saturated with moisture, which then works its way through walls to the inside of your home.

Another cause of 'damp'

If your house smells musty but you can't see any visual signs in your walls, you might have a build-up of excessive humidity under the floor area due to a lack of sub-floor ventilation, or if the soil underneath is damp due to poor drainage. The timber floorboards swell or bulge and so damp, musty air is trapped underneath.

Identifying damp

You can buy a relatively inexpensive moisture meter which will give you a better idea of the presence of excessive moisture, or you can hire a more sophisticated unit from an instrument hire specialist. Drill or punch a couple of small holes through any render in order for the instrument to read levels in the brick below.

If your damp walls are below ground level (e.g. a basement or garage) it may be because ground water is being forced through them, especially if the drainage behind the wall is inadequate. Or it may be condensation from inside due to poor ventilation, as mentioned above. You can know for sure by performing the following test:

1. Tape a 30 mm square piece of aluminium foil to the wall, with all four sides of the foil airtight.
2. Keep the foil on the wall for a couple of days, then remove and examine it. If the outside of the foil is moist, the problem is condensation.

If, on the other hand, the foil that was facing the wall is wet, the problem is water penetration.

Some solutions for damp

These depend on the cause and seriousness of the problem.

IF POOR DRAINAGE IS THE ISSUE

Inadequate, poorly built or poorly maintained drainage may be allowing storm water to accumulate near or under your house. Raised garden beds built right next to the walls may also be bridging the damp course. You need to change your drainage around the house; you could try laying 'ag' drain (a perforated flexible pipe) on the outside of the wall under the surface of the soil to take excess moisture away from the wall. You may need to consult a plumber to get this right, but the very least you can do is keep drains clean and clear.

Move any garden beds and other possible moisture bridges away from your walls.

Now, inside your home, the solution can be found in a paint can: waterproofing paint is formulated to be painted directly onto masonry walls and resist water pressure of up to 32 psi coming through. But you

must attack the problem from inside AND outside to really solve it.

DAMP-COURSING, PROFESSIONAL REPAIRS

If, after several months, these initial steps have made little or no difference you may need a new damp course. Professional installation of a new plastic barrier is the most effective resolution but it's also the most expensive. A whole course of bricks is removed one section at time to allow for the installation of the new barrier. Another professional treatment involves a chemical treatment where a series of holes are drilled in a brick course and a special chemical compound is injected into the brick under pressure.

DIY DAMP COURSING

You can attempt chemical dampcoursing yourself using nothing more than a hammer drill. It involves the same type of chemical fed into the brickwork with the aid of gravity; you can purchase a special kit for doing this (see useful info at the back of the book). Once you're purchased your kit:

1. Drill a series of holes, starting in the mortar line but at a downward angle towards and into the brick.

2. Place a series of specially designed feeder tubes (from the kit) into the holes and then fill with the chemical.

3. After an hour or so the chemical should have soaked down into the brick, where it will form a permanent waterproof course of brick.

A cream version of this chemical treatment, which is ideal for smaller jobs such as a chimney, is also available. The holes for the cream need only be drilled into a line of mortar and the cream is then injected with a standard caulking gun.

After a rising damp treatment has been completed you'll need to wait several months for the existing water in the wall to come to the surface and evaporate before refinishing.

FALLING DAMP

Exposed brick walls, particularly on the cooler, moister, south side of your home, may simply become saturated from direct rain. If this is the case, the wall needs to be covered with a protective coating of waterproof render, paint or even a clear coat if you don't want to lose the brick look. You should clean gutters and down-pipes and repair or replace them if needed.