Modular house construction is a technology that involves remote fabrication of a building’s sections called modules. Modules like walls, beams, slabs are manufactured off-site brought and assembled on-site. Contrary to conventional building methods which involve mixing concrete on-site and raising walls at the site, in modular house construction modules are fabricated from a factory under laboratory conditions prior to their assembly. This is done to de-congest construction sites, speed up construction, cut down general construction costs among other reasons.
After the modules are manufactured, they are transported to site using trailers and put in place using cranes. They are anchored in place and joined together using interconnections that consist nuts and bolts. The joints are covered with mortar to protect them from weather elements. This technology is still new in Uganda but common in other countries and used to construct both single and multi-story buildings.
With the ever growing population and demand for housing, the construction industry ought to evolve and adopt new more advanced technologies. Major aspects that contribute to the efficiency of construction method are but not limited to speed of construction, cost efficiency, quality of product of construction, relative simplicity or complexity. Examining Modular construction technology across these fronts will assess its efficiency as an alternative construction method to conventional house construction methods.
Speed of construction
The first and most profound attribute of this technology is that it provides for a speedy rate of construction. In conventional construction, sections are laid, one after the other. A wall can only be erect once the foundation is finished, cured and set and a wall also has to be finished before a roof is laid. All this requires a lot of time for setting and curing which can be further delayed due to bad weather.
Contrary to this, in modular construction sections are brought to site already set and finished and simply screwed into place one after the other. This allows for erection of various parts of the building concurrently. Foundation, walls and roof can all be assembled at the same time. No time required for setting or curing since they are brought onto site already finished. It is also less prone to hindrances like rain which may interrupt setting time of concrete as in conventional construction. Modular houses can be raised to completion in as fast as three days.
Cost of construction
This technology cuts down construction costs in four ways. First, less of both skilled and unskilled labor is required. Services of an engineer are less required since most of the design complexities are taken care of by the manufacturer like module measurements and specifications. When it comes to unskilled labor, no porters or brick layers are required, just a few semi-skilled personnel to man the cranes and others to screw the sections into place.
Secondly, the modules are also relatively cheaper when bought from a factory compared to fabricated on-site. This is because, buying for example a wall from a factory that fabricates walls on a large scale will probably be cheaper because the manufacturer enjoys economies of scale due to bulk production. Simply put, the cost of production per section reduces with larger units of production.
Finally, expenses are also saved on costs of scaffolding and form-work, timber frames used to support building parts before they set. Such accessories are only required for conventional construction methods but not for modular construction methods. And lastly, wastage is minimized since extra material like cement, sand not used in construction can be recycled to produce other modules.
Planning and budgeting
Planning and budgeting is made easier and more accurate. This is because rather than counting costs to the smallest materials like nails, cement or screws, costs are counted for already whole fabricated sections, like walls or slabs. This simplifies making of Bills Of Quantities, hence very small chances of errors due to over or under estimates. Planning is also simplified because this method eliminates unexpected delays, like changing weather.
This is because contrary to traditional construction methods that are affected by factors like weather, modular construction isn’t, hence construction projects can be accomplished within the set period of time. For example, in case of conventional construction, if it starts raining during the process of raising a wall, construction may be stalled, or worse, brought to a complete haul which translates into further expenses.
In modular construction which is hardly affected by the weather, delays are only limited to the manufacturer’s ability to deliver the construction modules at any given time. This is advantageous to contractors whose contracts are usually supposed to be done within a specific period of time otherwise translate into addition costs in form of compensations for bridge of contract.
Quality of construction works.
One could also argue that the sections manufactured by this method are of generally higher quality than the conventional methods. This is because, these elements are produced under ideal laboratory conditions dictated by the manufacturer. Temperature, pressure and other factors are all set to the highest most ideal level of accuracy hence a proportionally high level of precision and quality.
This is in comparison to the convention construction where construction is left vulnerable to uncertainties like changes in temperature or pressure of the atmosphere. Quality of construction is also increased since a manufacturer specialized in fabricating sections like walls gains a lot of experience over time and develops ways to produce higher quality products.
This construction method is more environmentally friendly.
Since excess materials are recycled, less pollutants are produced compared to conventional construction methods. Another reason is that since modules are made indoors in factories, resultant pollutants are easier to manage and appropriately disposed of. Pollutants like fumes from baking bricks, or water mixed with cement are easier contained unlike in conventional construction where they are openly disposed into the environment.
Those are a few merits of modular construction. Advances in technology are constantly simplifying construction at lower costs and high efficiency. With increasing technology, construction process may become so automated that it may be as simple as ordering parts online with measurements and specifications and arranging them the way a toddler arranges Legos.