Rising Damp

What is Rising Damp

Damp may well be termed the unseen "enemy" of your home. Your beautiful house will practically crumble to pieces if its moisture content is not properly addressed. Damp can cause damages to your house. A perpetually damp building might as well be the breeding ground of fungi that can either be dry rot or wet rot. Damp can ruin both the exterior and interior of your home. It can damage your wall paper, your house paint, your wall plastering and veneer and leave tell tale stains and marks on walls and ceilings. The worst thing that could happen is when damp has penetrated even the mortar and foundation of your house. When this happens, the structural stability of your home is greatly compromised.

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Damp and wood are the two components of a perfect ground for fungi and mould to thrive. Such occurrence is hazardous to the occupants' health as fungi and moulds have spores that could affect the respiratory system.

Intrusional Damp and Condensation

There are two ways in which your house can be damp - through intrusions and condensation. Intrusional dampness includes penetrating damp and rising damp.  Penetrating damp is the most common source of moisture in home interiors as it's easy enough for exterior moisture to seep through the walls, flooring and foundations.  Falling damp is cause by blockages and leaks in the gutter system. Rising damp is a more serious type of intrusional dampness as it could be summarized as ground water that is rising up a wall by way of the porous parts of the building.

Condensation is the moisture within the building brought on by bathing, cooking and faulty ventilation and heating system.  This "damp" situation is easily remedied by the use of a humidifier and/or making improvements the ventilation and heating system of the house.

Rising Damp Explained

Rising damp is very common primary cause o f decay to masonry materials.  No brick, concrete block or mortar is safe from rising damp. Rising damp is caused by moisture from the ground seeping into porous masonry building materials. The masonry can be brick, stone, mortar, concrete block and other related materials.  As the moisture penetrates the porous masonry evaporation occurs on either face of the affected wall making it possible for more moisture to seep in. This cycle continues unless the cause of the rising damp is located and fixed.

The capillary action is, however, self-limiting. The height of rising damp can be from 0.50 meters (18 inches) to 1.50 meters (5 feet). The rising damp leaves a water mark that becomes more evident on wall paper finishing and other interior finishing.

Causes of Rising Damp

Building foundations normally have a damp-proof course or DPC. A DPC is a simple barrier between the foundation or the base of the wall above the ground level and the main wall. The material should be impermeable to stop any possibility of damp rising through the barrier.  Modern DPCs are usually 0.5mm polyethylene sheeting.  Old home and buildings made use of glazed tiles, lead sheets and other maybe even hot tar and sand as DPC.  Failure of DPCs is one cause of rising damp.  Faulty water drainage system below the ground floor level is another cause of rising damp.  Faulty surface water drainage can also lead to rising damp. Correct diagnosis on the cause of rising damp is best done by a qualified professional.

Problems that might arise from Rising damp

Unsightly high-tide-like stains are not the only concerns with rising damp. The continuous dampness will ultimately affect the structural stability of the masonry walls. Ground water has natural salts like chloride, sulphate and nitrate. These salts are left on the walls when water has evaporated. The salts, aside from being unsightly due to their tendency to clump in groups, can also weaken the structure.  This could happen when these salts are crystallized into white efflorescence on affected walls. Salt attack can happen which could cause the total weakening and eventual pulverization of the stone wall. 

Salt deposits on the wall will remain even if the rising damp has been controlled. The salts on the walls have the capacity to absorb moisture from its surrounding. Hence, though the rising damp has been controlled the wall may still remain moist because of the accumulated salt content.

The constant dampness of the wall is conducive to the growth of dry rot, wet rot and other harmful moulds and fungi.  Any of this condition needs to be independently addressed from rising damp as any one of them is a health hazard to the occupants of the building.

Control and Dealing with Rising Damp

After a qualified diagnosis is done, immediately fix the problem to stop rising damp.  Maintenance should be included in routine housekeeping to prevent the recurrence of rising damp. Treatment can be in the form of installation of new DPCs or the injection of water-proofing chemicals. Care should be observed when deciding on the course of treatment. However, prevention is still the best action regarding rising damp.

Make sure that the storm and surface water (coming from downspouts and ground) does not lie against the base house walls. The ground paving should be sloped away from the house. Storm water drainage should be well-maintained to avoid accumulation of water.  In some cases where the general conditions of the soil and structure allow, the ground level is lowered to expose the DPC to facilitate the evaporation of moisture from a lower level. This option works for structures with no DPCs too.

Proper ventilation should be applied on underfloor to allow the moisture content of the soil to evaporate on side vents on the lower walls below the floor.

Whatprice provide a special service where you can get up to 5 quotes from local tradesmen to sort out your rising damp problems



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