Q.Which is the best brand of cement to be used for home construction?
The brand does not really matter. What matters mostly is the type of cement. Broadly, cement can be classified into 2 types - PPC and OPC. We are of the opinion that only PPC be used for normal home construction. More than the brand, the cement user needs to be concerned about 3 things - Type of cement ( PPC or OPC) , strength of cement and the expiry date of cement. These days, most commonly bought cement is 53 grade cement. What the number 53 stands for is that the cement would achieve 53 N/sqmm strength within 28 days of standard test conditions. Cement usually has a shelf life of 6 months. What is important is that there are no lumps in the cement bought and it is free flowing. This can be easily observed when the cement packet is opened and is poured for mixing. The only significant value addition brought in by a brand of cement is the consistency to the cement. We are of the opinion that almost all brands would have this part taken care of.
Q.How many days of curing should be done after concreting?
Technically speaking, it depends on the cement used and climatic conditions. As a standard practice however, we recommend 7 days of curing in which the concreted structural member remains wet all throughout this duration. The best practice would be to wrap the member with hessian cloth or similar materials so that the wetness remains for a longer duration and the effort of frequent spraying is reduced. For slabs, water ponding is an adopted practice. The important thing however is, at least 7 days the curing is done.
Q.Should soil test be done before house construction?
Let us first understand the purpose of a soil test. The house structure has a load. The load of every component in the house and anticipated load of people, equipment etc. The structure’s permanent weight - such as the weight of the slab, roof, beams, columns etc come under the category called dead load (DL) and the structure’s weight which is not permanent nature - such as the weight of people, machines, weight due to wind, rain all come under the category called Live load (LL). The combination of the DL and LL is the total load. For any structure to stand erect for reasonable time, the total load has to be transferred to the earth via foundation. Basically the soil test determines whether the existing soil conditions are capable enough to transfer this load successfully to mother earth and if not, a structural consultant is able to determine what foundation is to be done so that the structure’s total weight can be transferred uniformly to mother earth. The structural consultant decides the foundation system (such as raft, piling, isolated) based on the soil test and the anticipated total load. Now to specifically answer the question, it is always a good practice to get soil test done before start of any building if the owner expects to be reasonably sure about the long life of the building.
Q.Will the quality of water matter for concreting and plastering?
The simple answer - YES. Technically speaking, only potable water can be used for concreting. It should be understood why. What gives concrete it’s strength is the chemical reaction between cement and water. Actually, cement does not do much other than act as a strong adhesive agent between the aggregates. The strength of concrete significantly depends on the chemical reaction between cement and water. If water is not potable, meaning, if water has a lot of other molecules in it, this chemical reaction is interrupted with. Example - if salt water is used, there are a lot of chemical molecules in the water with sodium/pottassium being one of the most prominent ones. This can react with reactive aggregates the same way as alkalies in cement and cause undesirable results. Most technically accurate statement would be - water PH should be between 6 and 8 for use in concrete.
Q.Are wooden windows the best option?
Selection of wood plays the most important role from a long lasting perspective. The fact of the matter is that there are so many options available apart from wood as the choice of material for window frames. UPVC is a common option, so is aluminium, steel etc. Concrete window frames might be the cheapest option. The advantages of wooden windows: a. If wood is of superior quality, the windows last very long. b. It is aesthetically pleasing if it blends well with the overall design. Disadvantages: a. Wood selection is too critical. Warping, termite attack etc are common problems in wooden frames if the wood selection has gone wrong. b. Wood has to be painted as part of maintenance to protect it from nature’s effects, most common being termite attacks. c. Wooden windows are susceptible to effects of climate and may open/close with increased or decreased efforts according to climate due to swelling. d. Wooden windows with good wood is more expensive than substitute options.
Q.Is using fly ash brick a good choice as a building material for your house?
Simple answer - It depends. From a sustainability point of view, HIO any day recommends fly ash bricks over red bricks or concrete solid blocks or hollow blocks. Fly ash bricks are lighter, gives better compressive strength in almost all scenarios and has a better finish than concrete blocks which makes it easier for plastering or finishing. It becomes a good option from a cost perspective only in a scenario where the architect and the execution engineer is hand in hand and work so that a. the benefit of savings in labor of lead and lift of blocks b. the benefit of savings due to better structural design c. the benefit of savings in plastering material and labor are passed on to the home owner. In almost all other scenarios, from our experience, concrete blocks turn out to be cheaper.
Q.Is waterproofing necessary in toilets? Can it be avoided?
Water seeps through the slab through the pores that are there in the bathroom floor or walls and when water consistently falls on this surface, the water seeps through these pores or even micropores. What waterproofing does is closing all these pores by various methods so that the micropores sizes are smaller than the molecule sizes of water. The good practice is always to provide proper slopes in bathrooms so that water drains away properly before seepage.