Last winter I had been to western Nepal, where a house, belonging to my relatives, was under construction. They proudly showed me the bags of cement and steel of brands that’s been advertised as the best building material in the country. Nonetheless, these brands had quite satisfactory lab test results in a different construction sites where I had a chance to view them.
When I reached to the pile of sand and aggregates, I was dumbfounded. The sand seemed to be directly borrowed from a quarry site opened in a flatbed river of Terai. Soil, pebbles, pieces of cattle dung, rotting vegetation was visible on the surface easily. When I inquired if it was washed, they promptly said it’s been washed by the supplier – maybe it’s washed – but obviously it did not meet requirements. This reminded me of a proverb Biralo baner shradda- the supplier just did the holy ritual of washing- for the sake of cleaning.
Aggregates followed the similar story; supplier dredged the aggregates from river bed, washed them with a jet of water roughly as preliminary cleansing should be carried out, packed into a truck and dumped at construction sites. Aggregates weren’t the well graded mixture of crushed angular rock like they are supposed to be, but rather ugly round shaped pebbles piled up.
Here, for my relatives building house, the cement and steel are of good quality but sand and aggregates will definitely diminish the quality of construction. Any house made with materials of substandard quality will not perform as intended structurally even if the best construction practices are employed. Building a house where you can feel safe, starts with good building materials.
Talking about the quality of construction materials like cement, steel, chemicals; checking if they conform or don’t to the national standard prescribed by national agency is must. These materials which holds the Standard marks have been periodically checked by the standardizing institution for the quality indicators they achieve or don’t for different batches of production. Moreover, asking the manufacturing company about the test results of a specific batch of the cement/steel that we are going to buy ensures their quality.
Likely for sand and aggregates, they need to be free from soil content, organic materials and excessive amount of stone and dust as well as any other harmful contents that can affect the concrete strengthening process. Respective codes for the material quality define the minimum requirement for acceptable standard of these materials and material we are using should meet them at least. Aggregates ground from low strength rock like phyllite must be avoided. Strong rocks like quartzite make strong aggregates. Aggregates with more sharp edges are better for binding with mortar than rounded and smooth pebbles. Physical properties like strength, water absorption capacity, density have to be in accordance with the prevailing codes.
Timber is another important and expensive construction material. A well seasoned timber from heartwood of exogeneous plants like Sal, Sissoo has more uniform color, texture, grains. Treatment of timber ensures it safe against insects and termite attack. Good quality timber should be without any bending, warping or blemishes, durable and less permeable to water. Doors, windows and panels from quality timber make them long lasting.
OK! Now, we have gathered quality materials, will the house we are going to construct be all good and safe?? Maybe, Maybe not!
Here comes the most important step: Design. Design considers all the loads the structures need to bear; the strength of the materials and structural members like beams, columns possess. Design also takes in account special conditions like earthquake, wind pressure, snow/permafrost to waterlogging, black cotton soil in the foundation to floor area ratio, setback from the road to the maximum height of the building allowed etc. A qualified engineer who knows better about the site specific conditions and quality of materials can make an optimized design. An optimized design not only makes best structures from the resources available, it also determines the optimum amount of material requirement. This makes us safe financially also.
There are buildings standards and norms devised and maintained by governmental authorities for building construction like NBC 101, NBC110 etc. These standards help us to choose the right materials for our intended work, design philosophies to follow, best construction methodologies and workmanship. Government agencies publish guidelines for regulation of construction time to time, likewise one of them has just published by Ministry of Federal Affairs and Local Development.
Summing up, a safe house is only possible with good quality of materials with optimized design in the place of interest following the guidelines and standards.
Oops! I forgot to talk about paints, choose your colors and express yourself through your house and don’t forget to check if they conform with the standards or not- both for health and durability!
Guideline from MOFALD