Old to new construction joint

Construction joints are the joints where old substrate meet new substrate. It can happen due to several reasons.Some of them are.

1. Whenever there is an extension of a concrete slab from an existing one, like you want to increase the length of a room or to make new room by the side of existing one. These types of cases generally looks like below given image

It is clear from the above image that, there is an existing RCC slab, to which new concrete is to be combined
after the casting of new concrete, construction joint creates at the junction. Because of that construction joint ,two bodies never become monolithic (Shapes usually formed of a single block of a stone, or cast in one piece)  to each other. So, in result the construction joint formed will always become prone to water percolation       ( leakage & seepage). various methods are available out there in the market like "Arcylic based flexible strip"  and many more. but here in this article i would like to mention about a treatment which should be done during the casting process

                                                 Application of "BONDING AGENT" 

Independent waterproofing system

Before i go to the topic "independent wateproofing syastem" let us discuss about some conventional systems. We are familiar with some conventional water proofing systems

First category is coating

1. Single component coating
2. Two component coating

Second is membrane treatment, 

membranes available so far are bitumen based membranes like Tarfelt, Polyester Reinforced Membrane etc. They are available on different thicknesses and of various price range.Lets discuss about them in some details

Waterproofing coating- Coating treatment is widely used in our country for some few years.For horizontal treatment of surfaces like terrace, terrace garden,podium slab, sunken slab; two component chemical is generally preferred. Two component product has compound A (powder) + compound B(Polymer liquid).
               Many companies are there, across the globe placed there two component waterproofing chemical in market. Every product has its different powder to liquid ratio; here let me clarify that as far as two component products are concerned, powder to liquid ratio is a very crucial part for determining the quality of final outcome.More the polymer liquid content with respect to powder, higher will be the quality of coating because higher polymer content leads to more flexible coating.
           
                         The most important thing i want  to discuss here is that

                  " waterproofing coating is a dependent waterproofing system"

                     Let me explain by "dependent waterproofing system" what i mean 

      when any type of brush applied coating is done on any surface, that completely sticks over the surface and become dependent on the stability of the surface. If any kind of deformation, undulation occurs on the substrate; that will reflect on the coating. If crack develops on the surface, coating will also be cracked, no matter how flexible the coating is.

                    "let me show you how coating functions on the concrete surface" 

                       

Method of flooring in sunken slab(Toilet)

This is a latest methodology developed of flooring in sunken slab(Toilet). In this system "groove cut drain" of 2" wide is to made all around 6" away from wall; direction of slope towards the "groove cut drain, so that if water reaches to the flooring that will rolled down to the groove cut drain.Through  drain, water will go to the escape pipe and flow out. 

Below given image shows how above drawing is implemented in real scenario.Groove cut all around will be filled with sand so that it will not be chocked with something else. This drain end at point where escape pipe is to give. Waterproof coating should be done inside the drain 

Finish the surface with cement slurry 

Than,Sanitary fittings are to be done.

This groove cut system actually prevents water to be jammed within sanitary pipes.

Waterproofing of wall during construction

Cement based polymer modified brick masonry coating 

Damp wall

Waterproofing of building

   We are going to discuss about waterproofing systems. we require waterproofing at many places on a buildings, some of them are

Terrace
Toilet sunken portion
Basement
Septic tank
Overhead tank
Exterior walls
Septic tank
swimming pool etc....

Terrace 

Toilet sunken portion

Basement waterproofing

Septic tank

      As we know that in India, there is high temperature variation. It varies from 10 degrees in winters to 50 degrees celsius in summer.We also have lots of rains in rainy season This type of high variation creates lots of adverse effect on structure of a building. there will expansion of concrete at high temperature and contraction at low. This expansion and contraction may create cracks. These cracks leads to water ingress, leakage and seepage.
        Sometime honeycombs and voids exists inside the concrete structure which is also responsible for water percolation. there are several reasons because of them it happens like low work ability of concrete mix, absence of vibration, high water cement ratio etc.
       Most common water proofing system for concrete slab we have right now is brush applied coating system (either one component or 2 components product)