Cornwall Damp Proofing Treatment, Damp Proofing Specialists in Cornwall

Cornwall Damp Proofing Treatment

Damp

Structural dampness is the presence of unwanted moisture in the structure of a building, either the result of intrusion from outside or condensation from within the structure.

A high proportion of damp problems in buildings are caused by condensation, rain penetration or rising damp.

Dampness tends to cause secondary damage to a building. The unwanted moisture enables the growth of various fungi in wood, causing rot or mould health issues.

Plaster and paint deteriorate and wallpaper loosens. Stains from water, salts and mould damage surfaces.

Rising & Penetrating

The highest airborne mould concentrations are found in buildings where significant mould infestation has occurred, usually as a result of severe water intrusion or flood damage.

Moulds can grow on almost any surface and occur where there is a lot of moisture from structural problems such as leaky roofs or high humidity levels.
Airborne mould concentrations have the potential to be inhaled and can have health effects.

Externally, mortar may crumble and salt stains may appear on the walls. Steel and iron fasteners rust.
It may also cause a poor indoor air quality and respiratory illness in occupants. In extreme cases, mortar or plaster may fall away from the affected wall.

Rising Damp

Rising damp is the term used to describe dampness in a wall structure, where there is higher moisture content at the base of the wall, which rises further up the wall.

The problem of rising damp can be identified in a number of different ways:

Damaged internal decoration – damp, discoloured tidemarks on internal decor.
Damaged Plaster – blistering, salting and disintegration
Rotting skirting boards, floor timbers – wet rot decay
Localised dampness – dampness on walls rarely exceeds one metre above ground level, but may go much higher in extreme cases

Causes of Rising Damp

Lack of damp proof course
Break down of an existing damp proof course
External ground level being higher than internal floor level bridging existing damp proof course
A build-up of rubble/mortar inside a cavity wall causing bridging of damp proof course
Internal plaster work bridging an existing damp proof course
Enduring damp at the base of the wall caused by previous water penetration
Condensation at the base of a wall due to inadequate ventilation
Defective / leaking water pipes allowing ingress of water

Rising Damp Treatment

In many cases, damp is caused by “bridging” of a damp-proof course that is otherwise working effectively.

For example, a flower bed next to an affected wall might result in soil being piled up against the wall above the level of the DPC.

In this example, moisture from the ground would be able to ingress through the wall from the soil.

Such a damp problem could be rectified by simply lowering the flower bed to below DPC level.

Injection of a liquid chemical damp proof course (DPC Injection)

“Cornwall Damproofing use the method of injecting a liquid into bricks or mortar, this is the most common method of treating rising damp.”

Penetrating Damp

Rain Penetration (also known as “penetrating damp” is a common form of dampness in buildings.
It can occur through walls, roofs, or through openings (e.g. window reveals).

Water will often penetrate the outer envelope of a building and appear inside.

Common defects include:

Roof defects such as faulty flashing, cracked or missing slates or tiles.
Faults in the brickwork or masonry such as missing or cracked pointing. Porous bricks or stones.
Missing or defective seals around windows and doors.
Blocked weep holes.
Missing or defective trays in cavity walls.

Walls

Rain penetration is most often associated with single-skin walls, but can also occur through cavity walls – e.g. by tracking across wall ties.

Primary Causes

Cracks in render and masonry provide a pathway for damp to penetrate.

The primary cause of rain penetration through walls is defects in the masonry – e.g.:

Porous masonry (i.e. under-fired bricks, porous stone, or porous mortar)
Cracks
Defective pointing
Unfilled joints and perpends
Defective seals around doors and windows
Holes in walls – e.g. where cables or pipes protrude
Defective render

Exacerbators of Rain Penetration

Where a wall suffers from one or more of the primary causes of rain penetration listed above, the problem can be made worse by one of the following exacerbators of rain penetration:

Water will often penetrate the outer envelope of a building and appear inside.

Common defects include:

Defective rainwater goods
Moss growth on roof tiles (causing blockage of rainwater goods)
Defective or missing window sills (causing high concentrations of rainwater to bear on section of wall below window)
Non-breathable coatings such as acrylic masonry paints – especially where applied to a poorly prepared masonry substrate
Location/aspect of wall – e.g. walls facing prevailing wind are more prone to rain penetration problems
Periods of extreme rainfall – walls that are normally thick enough to prevent rainfall from reaching the inner face can be overwhelmed during periods of heavy, persistent rainfall

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