If you are constructing a RCC house, from the day you open that first bag of Portland cement bag you will require water – lots and lots of water. When I started my construction I had a 500-liter tank to store water and very soon that I realized that it was not even enough for half a day’s work.
|I had this water reserve so I could breathe easy.
Despite that I had to go through a couple sleepless nights
to get the water to the site which was about 200 meters away!
Luckily for me I had a pond at my backyard, which enabled me to meet the needs. Even then because my area experiences frequent power cuts, I had to look for alternative means to make water available in the site. Water is required not only for preparation of mortar, mixing of cement concrete, but also for curing at various stages.
Ask about the importance of water, your contractor will tell you that the very strength of your house will depend on how much water went into your construction. Also both the quality and quantity of water has much effect on the strength of mortar and cement concrete in construction work.
|Curing of one of the early column footing in my
construction. This is about 2 weeks from the day
the structure was built.
So before you start work make sure you have access to portable water. It could be a well, a boring or the supply lines provided by your local civic bodies. And have adequate storage. What I did was built the septic tank first and used it to store water. Trust me, you can’t fathom the amount of water required as the construction progresses, particularly on the day you are laying your concrete roof.
Also buy a 0.5 or 1 horse power water pump. It’s inexpensive and worth every penny you put in.
Now, when it comes to water for your construction here’s what you need to look at:
Quality of water: Basically, the water you use for both mixing and curing should not have any chemicals, suspended muddy particles or organic growth like algae, weeds, etc. The thumb rule is that if the water can be used for bathing, if not drinking it’s okay.
Quantity of Water: Many times in spite of using best raw materials, cement and tested water; concrete does not provide required results. This is basically because the water-cement-sand ratio used was either less or more. Since it’s a chemical process when the water is mixed in mortar, it reacts with cement and forms a binding paste. The water actually helps in filling the small spaces in the sand creating a close cohesion of sand particles and cement.
You will see many a time workers use more water while making the concrete mix because it makes it easier for them to work. This is a bad practice because additional water weakens the strength of cement paste and weakens the adhesive quality of the Portland cement. So always insist that the workers thoroughly mix the sand and cement first and then add water.
Many owners and contractors alike fail to understand the importance of curing and leave it to the workers’ discretion. The ill effects of poor curing are not visible immediately, so contractors get away with it easily. Watering the structure for a certain period of time is necessary to control the rate and extent of moisture loss from concrete and also to maintain a perfect temperature of concrete to set in its early ages. This will also maintain a uniform temperature throughout the structure, which means lesser instances of uneven shrinkage and subsequent cracks.
So when do you start the curing process? The mostly followed rule is if the structure was prepared in the evening, the curing should start in the following morning. In my case I really found it difficult to keep structures, mostly the pillars wet throughout day.
So what I did was I wrapped the pillars with hessian or gunny cloth and sprayed water on them. The cloth absorbed and retained the water for longer period and spraying water twice a day was enough for me.
As for the extent of the curing process, seven days for pillars and foundation footings, 2-3 days for brickwork and plaster and 10 days for the roof is fair enough.