Why You Need A Material Schedule For Your Project - Osaz' Enobakhare

Sometimes the use of direct labour in conjunction with supervisory and quality control inputs from one or two professionals is seen as a more budget-friendly approach to the delivery of a project, especially small-scale projects. Other times, the project owner may choose to be engaged directly in purchasing and organizing the supply of construction materials to their site, also in a bid to save cost. Whatever the case may be, whether it’s your personal project or as a group, it is important to know what and what you should expect at completion. You don’t plant grapes and expect to reap blueberries. A project for example, a building development is essentially a product of the use of materials and workmanship. You don’t order for tiles and expect to see epoxy flooring; neither would you see a classic brick wall when you actually paid for blocks.

The usefulness of a material schedule is undoubted. You may never know it until you lose money buying the wrong or a substandard material at the same price as the original or even more. It is that piece of document that shows you the types, sizes, quantities, quality specifications and sometimes current price of all the materials you would need for a project from start to finish. It is not the same as a Bill of Quantities (B.O.Q) or Priced Bill of Quantities which gives brief details of all the items of work in a construction project and cost included respectively, it doesn’t give you the work item or work processes, it only deals with the materials aspect.

The Material Schedule is presented in such a way that the user can easily identify with what materials will be used in the construction of his/her project and it often reveals approximate quantity estimates of all the materials needed with minimal allowance for wastage. Usually the material schedule is a construction document prepared after all the relevant designs/drawings has been completed so that at no point is any material is omitted due to incomplete architectural and engineering details and a thorough market survey has been done to check availability and current prices of the required materials. It is often done in conjunction with the owner’s specifications.

When engaging a contractor, it is important to ask for a material schedule so that you can follow up on the quality of materials used for your work. If the materials used are not those you have agreed on as duly reflected on the material schedule in the absence of a pro-work variation, you can call for a replacement. But if there are no documents to show material specifications, then you can expect anything. Sometimes regret may follow; this is particularly the case when a nominated supplier is engaged without a material schedule to back up your claims on the specs of the materials ordered for. Take for instance, you need a simple timber (wood) to construct your roof carcass, if you don’t specify the product type, size and condition (e.g. Mahogany Hardwood, 50 x 75mm full lengths, new and smooth) but just say supply me ‘wood for roofing’ who is to blame when a truckload of used fragile softwood is brought to your site and workers begin installing them?  Although the material schedule comes at a cost, it is worth it.

Why It Is Structurally Wrong To Build Directly On Plain Ground - Osaz’ ENOBAKHARE

As construction cost rises due to attendant rise in prices of building materials, the trend of building houses directly on plain ground has been observed to be on the increase especially by unscrupulous developers and contractors. Having carried out an independent monitoring of construction activities in some areas in the Ajah axis of Lagos lately, it became obvious that in order to save cost people have resorted to constructing buildings directly on plain grounds.

The awkward idea been adopted in most of the cases under study is to sand-fill the land, level and compact it with the use of machines and the construct a reinforced concrete strip foundation directly over it without recourse to minimum construction/engineering standards.

They do so very quickly so that before any of the regulatory bodies saddled with the responsibility of building control gets wind of their ill act, they are already on super-structure level at which point it is burdensome to ascertain how the foundation was actually built. 

On a particular site, using this vague method the entire foundation including the ground floor slab was put up in one week and by the next week, they were already building up the walls and frame. Dishonest developers thrive in such indecent acts and sell or lease these buildings to unsuspecting prospective buyers who in-turn occupy them or cause others to do so by way of lease/rent too. There is no consideration for lives and properties put at risk of an imminent collapse even as some of the buildings observed are already exhibiting symptoms of instability and sick building syndrome pre-occupancy.

Five years post-occupancy, the building over-settles (or sink) and then tilt in a particular direction. When asked, some of these developers claim that before there will be any major issue with the building they would have recouped the returns on their investment and its left to the new owner to do a repair by way of underpinning as the need arises. To know that some greedy professionals have joined the bandwagon of quacks in delivering such poor structures is condemnable. This act should not be encouraged in any form.

Here are some structural considerations; normally after leveling and compacting operation has been carried out on a sand-filled land it still remains a made-up ground. Although the land becomes stiff at sub-surface levels, this doesn’t in anyway erase the fact that the underlying bad soil (or peat) remains intact and retains its poor attributes. Peats are highly compressible soils and will naturally compress upon the impact of load. As this happen, the building will settle indifferentially, especially during seasonal changes and mass movement of the earth; which occurs at various times of the year.  Such structural anomaly often leads to poor stability of the building and eventually a collapse if unable to bear the load, especially for single or multi-storied structures.

Rising cost of building materials should not be a yardstick to adopt poor construction methods in the construction of buildings and estate infrastructure anywhere. The authorities should not turn a blind eye to such activities that jeopardizes or threatens the lives of people as well as the overall health of the built environment. Project owners and developers should not connive with contractors or builders to manipulate well established engineering prinicples. It is important to select a good contractor for your projects. Yes, there is room for adopting cost-saving methodologies like the use of dry construction methods, cold brick construction, etc but bad construction methods is never the way to go.   

Dredging to Sand-fill an Estate: The Tricks and Gains -Osaz’ ENOBAKHARE

Developing housing or industrial estates close to large water bodies throw open the option of dredging to sand-fill with the aim of reclamation or just to prepare the site for the construction of buildings and infrastructure on it and/or to get sand for the actual construction. In more extensive application, sands can be dredged to stockpile and sell. Basically, for estate development the option of dredging is often weighed alongside the possibility and cost-effectiveness of the alternative approach of trucking sand from nearby sources.

Contrary to popular opinions, industry estimates reveal that for mini-estates (of 5 acres or less) located close to water bodies with shallow fill depth (not exceeding 1-metre) and where manual dredging is prohibited, the option of trucking has proven to be cheaper than mechanical/hydraulic dredging. 

Besides unlike dredging which restricts the user to the particular quality of sand deposits available in that water body at the material time, trucking also allows for the use of a variety of filling materials. However beyond these rare scenarios, mechanical/hydraulic dredging remains the best approach.

Although manual dredging is still the cheapest form of dredging, it is tedious, relatively slow and highly risky hence no longer in vogue. Mechanical/Hydraulic dredging allows for the digging up of mud, sand, gravel, pebbles, rocks and other deposit from the bottom or sidelines of the water bodies by means of a mechanically or hydraulic-driven equipment known as a dredge (or dredger). There are various types of dredgers each defined by its mode of operation. However local industry folks can easily relate with two popular types which are Cutter-Section and Plain/Jet Suction Dredgers.  The striking difference is that the former cuts into the bed, agitates it and sucks up the mixture before transferring it to the end point through a pipeline while the Suction dredger simply sucks up the sand directly and transfer.

Dredging activities requires you to obtain a license/approval which is given by the appropriate authorities after providing relevant documents. These conditions defer from state to state across Nigeria but generally a sand search is often conducted at first to determine the source, availability/quantity and quality of sand in the water body or shoreline to be dredged. This sand search result is often the first and major item developers look out for in a hydrological survey carried out pre-dredging. There is really no need attempting to dredge what is not available in required quantities? A Bathymetric survey is also carried out to determine the depth and bed ‘topography’. Both surveys are often used interchangeably to mean the same thing but they actually have their specifics. An Environmental Impact Assessment (EIA) is then carried out to determine the level of impact the proposed dredging activity will cause to the environment. 

The most suitable type of dredger to be used for a project is largely determined by the cost of purchase or leasing, the size of task to be performed, pumping requirements par efficiency as well as the nature of the sand deposits present. From observation, most small estate owners normally opt for suction dredgers of 8 – 14 inches with sand capacity averaging 350 cubic-metres of sand per hour; relatively cheaper to purchase or lease.  Larger cutter-section dredgers sizing up to 18 inches or more with sand capacity reaching 1000 cubic-metres of sand per hour is in high demand among medium and large estates’ owners. Experience shows that the rate of breakdown of jet suction dredgers on sites is relatively higher than the cutter-section type owing to their inability to withstand stresses associated with sucking up very stiff clay and rocks. But in any case, with a good dredger pumping sand constantly into your site, the heavy cost and risks associated with long-distance sand trucking is completely erased.