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‘Rising Damp’ Can and Should be Treated

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Rising damp is a relatively common waterproofing problem seen in brick and masonry buildings. As the name suggests, rising damp indicates the movement of water from below ground, upwards along walls, causing the unsightly appearance of damp, peeled or bubbled paint and plaster, and a water tide mark internally as well as efflorescence, water tide mark and crumbling mortar externally.

The issue of rising damp is typically seen in older buildings and is a significant challenge in repair and protection of heritage buildings.  Rising damp may also be encountered in new construction, albeit an outcome of different waterproofing problems. Water that is present under or around a structure gets sucked upwards through pores and capillaries. As the water moves, dissolved salts from the sub ground soil as well as salts of the building structure itself, get dissolved in the moving water. As the water evaporates it leaves behind high salt concentrations in the wall, which also attracts airborne moisture and furthers the eroding and blistering seen. The masonry, attacked by this high salt load begins to crumple and deteriorate. In sea facing areas, the presence of salt in the water and soil adds another level of problems for such areas.

The trapped moisture makes the damp surface rife for growth of mold and other undesirables in living spaces. Clearly this is not an acceptable circumstance within any home or office. Furthermore, the damage caused to our heritage structures results in the loss of our thousands of years old history.

So where does this water come from?

Rising Damp 1–    In older and heritage buildings the rise of ground water could be an outcome of a high water table pushing against aging masonry. Particularly in the rainy season, when water tables tend to rise, this becomes a more precipitous issue.
–    In new construction, the inadequate damp proofing such as using strips of rubber or plastic, slate or stone courses or bitumen sheets can result in ground water rising and damaging a structure. There is a relatively new process seen in construction these days of including six inches of reinforced concrete which is intended to serve as damp proofing before a wall is raised. The problem in this technique is that concrete itself is hydrophilic or water loving and although concrete can be less porous than brick, it too will be as susceptible to rising damp under the conditions described herein. Adequate waterproofing against rising damp will still be needed.
–    Condensation dampness, where inadequate ventilation as well as significant differences in humidity encourages water to condense and collect below a structure, can cause rising dampness.  Bathrooms in particular offer an ideal site for excessive moisture to collect and condense. This water too contributes to the collected condensation under a structure. In-deed, condensation dampness is a common rising damp problem in several areas of India where humidity is high, even though water table may not be high.

Please note that buildings can face dampness due to the penetration of rainwater along their walls (horizontal dampness), or leaks from the roof or terrace, but these are other waterproofing problems and not rising damp.

It is important to point out that if dampness is seen in an area of footing failure, grade slab, foundation cracks or floor dampness is encountered it is not necessarily the same as rising damp. Rather, these are serious structural issues where a structural experts advice must be sought.

Rising Damp 2In the case of rising damp, the first thing to review is the slope of the soil surrounding the structure.  As far as possible the slope should draw water away from the building. In the case of condensation rising damp, efforts must be made to increase the sub floor ventilation, which could fix minor rising damp issues. That said, brick and masonry are porous material and if water is present near them, they will absorb it. The correct treatment re-quires these building materials themselves to be permanently made impermeable to absorption of water. As a leading waterproofing company, Tech Dry offers a variety of products that can be reviewed at our website www.techdryindia.com to help in the waterproofing of terraces, footings, grade slabs, retaining walls and other structural parts of the building.  We also have very successful waterproofing methodologies using our products for waterproofing new construction bathrooms as well as repair projects. Staying on the subject of rising damp however, it is clear that any water underneath a structure can result in rising damp.

Rising damp through caplillary actionAttempts to treat rising damp through traditional methods have included costly procedures such as taking out old mortar and bricks close to the floor to introduce some type of waterproofing sheet. Not only costly and generally inadequate, this also requires providing structural stability to the wall during treatment and could result in settlement of the wall.  It is particularly more risky in the case of old and heritage structures.

Creating a damp proof course in the masonry is Tech Dry’s approach and involves establishing a permanent damp proof zone using the impregnation product Protekta DPC which once established never gets washed out as it becomes integral with the brick masonry.   While pressure injecting of siloxanes has been tried by some, that method is problematic.  The pressure itself tends to damage the already compromised masonry and brick.  The ability of the product to penetrate evenly, not leak through fissures and remain bound permanently are other problems.

Our treatment creates a damp proof course in the brick/concrete and masonry involves using our product Protekta DPC.  This is a unique impregnant formulation of silicones, silanes and siloxanes. The technique requires the saturation of the treatment surface but does not require any pressure injecting.  Rather, Protekta DPC flows through gravity feed.  As it slowly saturates the masonry, it is able to penetrate even the smallest pores and become integral to the masonry. Once saturation is complete, the surface is allowed to naturally air dry and as it does, the Protekta DPC enhanced surface is permanently hydrophobic or water repellent leaving no change to surface color or appearance. It can then be replastered and painted over to achieve a new look that will no longer have any problems with rising damp.

For further details:
Tech Dry (India) Pvt. Ltd.
# 877, 1st Cross, Krishna Temple Road,
1st Stage, Indiranagar, Bangalore 560 038,
Ph: 080-25255406 / 294
e-mail: contact@techdryindia.com www.techdryindia.com

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