Unfortunately, dampness is an issue in many older buildings.

This problem can make an otherwise beautiful building a very unpleasant space to occupy, so much so that it drives the occupants to distraction.

Contrary to perceived wisdom, it is not due to the process known as 'rising damp', as damp is a symptom (all be it an unpleasant one) of another problem or problems. Quite often it is actually due to far simpler issues, such as interior or exterior changes modifications to the building.

First, a little history: A Damp-proof course (DPC) is an impervious layer built into a wall. It should be placed little above ground level. This is in order that moisture rising up the wall via capillary attraction is prevented.

The DPCs preventing water penetration became compulsory in Britain in 1875. DPCs have varied over the years. Modern DPCs are usually plastic, and in some cases, liquid. Older DPCs were often bitumen, but many examples of slate or even occasionally, lead.

Now, about 'Rising damp'. What is it?  Well, as much as this may sound strange, it most likely doesn't exist. As stated above, dampness is a major problem in older homes, but please, keep reading.

Invariably, the damp is actually a symptom of another problem. Attempting to 'fix' the damp fails to address the true cause of the problem, frequently fails and most likely cause more harm than good.

The most common causes of damp being:

Homes with a DPC:

• Pavements/path, driveways, even lawns and garden beds that have been raised the ground above the DPC, allowing water to penetrate into the wall
• Leaking roofs, this allows water to 'trickle' ground-wards, within the wall
• Leaking gutters or down pipes
• Drip cills becoming blocked or deteriorating
• Burst plumbing pipes. E.G. radiators, mains feeds, drains, exterior taps
• Poor drainage; water gathering under the wooden floor of a home
• Blocked vents/air bricks
• Debris under wooden floors causing capillary rising of water (often in conjunction with the above)

Homes without a DPC:

• Pavements/path, driveways, even lawns and garden beds that have been raised the ground above the DPC, allowing water to penetrate into the wall
• Leaking roofs, this allows water to 'trickle' downwards within the wall
• Leaking gutters or down pipes
• Drip cills becoming blocked or deteriorating
• Burst plumbing pipes. E.G. radiators, mains feeds, drains, exterior taps
• Poor drainage; water gathering under the wooden floor of a home
• Blocked vents/air bricks
• Acrylic paints, either inside or outside not allowing the walls to 'breathe'
• Cement based mortars used in re-pointing the stone/brickwork
• Cement based renders not allowing the walls to breath
• Debris under wooden floors causing capillary rising of water (often in conjunction with the above)
• Air drains being interfered with - this usually means filled in with soil preventing evaporation of moisture

Quite often people are told that their "damp course has failed" and advised (at great cost) to have a liquid injection damp course installed.

Unfortunately this is seen as an acceptable option, largely as the average home-owner is not a specialist in historic homes. (Neither are sellers of damp proof solutions)  Home-owners should ask one question in response to this advice; Why? Why has it failed?

The 'Why?' question is even more relevant in an older home that never had a DPC at all. Why now?  Could it be:

• Due to work carried out by the council in the few years, such as resurfacing the pavement or adjoining road?
• Due to the new rendering/harling that was done?
• The new (non breathing acrylic) paint, inside or out?
• Because of the severe cold last winter causing water pipes to leak?

Or a combination of several of the above? Should the problem be one of these issues, please be aware that it could take several years for problems to manifest themselves

One thing that is almost 99.9% guaranteed is that buildings do not spontaneously develop rising damp. 'Failed' DPCs are not very common, and become less so, the newer the home. And many older homes have survived one, two, three centuries of more quite happily without a DPC and without 'rising damp'.

Chances are your damp problems are due to one of the above issues.

Dampness in buildings is by no means a new problem, displayed in these quotes.

In some localities damp-proof courses are formed of asphalted felt, or with slates set in cement ; these latter are rather liable to crack, and thin impervious stones, or courses of Staffordshire bricks in cement, are better. Sheet lead has been used for the same purpose, and is most efficacious, but very expensive.

Advanced Building Construction Manual for Students 1893

All floors near the ground should be ventilated, to secure a perfect circulation of air round all their parts. This is easily done by inserting air bricks in the walls.
For the same purpose openings should be left in the sleeper walls carrying the intermediate wall plates of ground floors.
The ground below the floor should be thoroughly drained, and covered with ashes and quicklime. It is sometimes concreted all over to prevent damp from rising.

Advice from a construction manual 1880's

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