3 Ws & 1 H of Waterproofing of Concrete & Masonry
Waterproofing is the most known or unknown subject and probably confusing also today.
Most known
Reasons- highest no of consultants, manufacturers, and Applicators do exist today in the field of waterproofing.
Most unknown
Reasons-Despite the above, the users are still at the receiving end facing a bitter experience.
Confusing
Reasons- In my +25 years in the field of waterproofing and construction chemicals, many times came across customers informing they were better off before the waterproofing had been done. Some people call it a “Myth” and others use some different words to express their frustrations. Another issue that has been experienced the item of waterproofing does not get adequate attention being the last operation to execute in most cases of construction.
Let us look at it from the angle of 5 W s and 1 H
What are the Problem
Normally noticed -water leakages & seepages thru’ terrace, exterior walls, wet areas; dampness & seepages near the floor — wall junction, basement car park, junction/ joints at dissimilar materials, expansion joints, many other major and the minor problem like cracks, honeycombing and other defects due to construction deficiency, though, not highlighted much here, but these issues also contribute to waterproofing problem finally.
Why such situation
common causes — Inadequate study of the problem; lack of knowledge, experience, and expertise regarding materials, specification, systems, and not enough detailing, termination, and protection system in critical areas.
who are responsible
I would consider the entire waterproofing fraternity including users either partly or fully. However, there are few exceptions to prove the rule.
# When Waterproofing should be done # A group of engineers believes that they can make good concrete structures without the need for waterproofing, even for long term performances, but it is far away from reality. Concrete is a magical material and it is the second-largest material in use after water. Today over 25 Billion MT of concrete is in use and increasing every day. Looking into the material science of concrete, like any other material, it has a long list of advantages but few disadvantages too. Concrete has a limited ability to withstand long term exposure to the environment and vulnerable to thermal changes resulting in cracks; followed by attacks from other chemicals like carbon dioxide, sulfate, and chloride from the environment resulting in a reduction in durability and construction deficiency results in honeycombing/ voids and few other problems, which all lead to deterioration of concrete.
The best ways to tackle that problem is to envelop the building/structure right from the Basement Floor, Retaining walls, Exterior walls, Terrace along with the other areas like Wet areas, Podium, car Parks, Water Tanks, Swimming Pools, Expansion Joints and sometimes Intermediate Floors too.
It is unwise to keep the waterproofing pending till the problem occurs, since, it may end up with a Fat expenditure towards to cover waterproofing and other damages. As per the Thumb rule — the cost of a waterproofing system is around 2% of the total cost of building, but it can save one from 80% of the problem avoiding any major expenses.
How to Achieve a Flawless Waterproofing System
a) Detailed Study of the condition of the structure and relevant issues to tackle.
b) Thorough cleaning of the entire surface area followed by correction of cracks and all other visible defects adequately along with the treating of all construction joints, unless taken care of during the construction process. All activities to be undertaken after the curing of concrete for at least 28 days. Curing of concrete is to be done for seven days to have long-term benefits like durability. Concrete Admixture and Integral Waterproofing chemicals are the part and parcel of concrete today during pouring/casting.
c) Selection of the Right Material for Waterproofing as there are several choices with varied performance criteria and cost, e.g., Preformed Membrane; Chemical Coating; Liquid Applied Membrane; Crystalline Compounds but followed by a flexible coating material to have the adequate crack bridging performance. There are again many varieties in each category of waterproofing material. The selection of waterproofing material has to be appropriate to suit the different set performance criteria and meeting the techno-commercial feasibility. Selection processes of material is not discussed here as it would be lengthy and can be done separately.
d) A waterproofing system is to be designed keeping all parameters and variables in mind followed by detailing each critical section and termination. A step by step application methodology to be given for ease of understanding and for better supervision and quality check. The strict conditions must be laid barring the execution of any other work simultaneously during the waterproofing work, till it is completed and protected properly. A large number of waterproofing works could not perform flawlessly due to external damages, other than the natural calamities.
e) Qualifying the right Applicators may be the key to trouble-free performance since the best-chosen material may turn out to be a failure due to faulty and improper application. The selection criteria for applicators could be their knowledge level, expertise, past experience, and available infrastructure. The above details also will help to decide the allocation of the right size of the job to each applicator.
f) There is no substitution for good supervision.
g) Final steps are the Check and Test- A checklist of deviation is to be made by physical observation by a Tri-Party Team of Applicator — Main Contractor, PMC, if any and Customer and after rectification, re-inspection is to be done to verify. Pond Test is to be done on Terrace (and wherever possible) as per the guidelines of ASTM D 5759–98 (2013). All Pond Test needs to be carried out before laying of final protection over waterproofing treatment.
Cnclusion
Shared the above based on +25 years of experience in waterproofing and construction chemicals.
The right approach would be finalizing the waterproofing system with detailed working at the time of designing of building and tender the waterproofing work along with tender for the main work to have the proper importance of waterproofing work. Fortunately, today many major projects are following the same but other works also should start to follow a similar methodology.
There is the availability of enough knowledge and expertise in the country today who can give the right solution to remove the darkness from the subject of waterproofing.
Complete design of the system with the right material, application details, selection of suitable applicator, supervision, etc., may be provided for not only waterproofing but also for repair and rehabilitation of different structures
In view of my long exposure to the above subject, I can contribute effectively towards the above also.
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