Yesterday, my colleague asked me something on IBS; IBS has obviously been one of my favourite topics, and in fact, I have always been a believer in certain forms of IBS systems. I was the one who had 'pushed' for the introduction of system formwork usage in my office - since then, we used a lot of steel forms, table forms, the aluminium formwork system such as MIVAN, and most recently, the DOKA system.
The DOKA system formwork used at Menara Binjai.
Anyways, IBS is much more than just system formwork. I would say system formwork can only get 0.5 or 0.6 multiplier in terms of IBS scoring, cos it is still casted in-situ. In fact, The IBS is a system, or rather method of construction where the various components are constructed, and then assembled on site - similar like LEGO. =)
Precast elements plays a significant role in IBS.
- Pre-cast concrete frames, panels, columns etc
- Formwork systems - tunnel forms, permanent steel formworks
- Steel frame systems - portal frame, roof trusses
- Prefabricated timber frames - i.e. for roof trusses
- Block work systems - lightweight concrete blocks and so on...
My colleague got a little shock to see her newly purchased house - being built the un-conventional way - in the form of IBS. After explaining a bit to her on IBS systems, I have decided to come up with this post - to further explain on the advantages and... of course, disadvantages of IBS systems. Nothing is perfect in this world... so there are always pros and cons. =)
What would be the main advantages of the usage of Industrialized Building Systems?
The immediate advantage is... discounts on levy charges for contractors!!!!! Sorry - this is of course in the contractor's point of view - which would have plenty of advantages. But with due respect, it is the buyers/end users who need to worry about it - so here are some of the strong points.
Precast panels used in linked/terrace houses.
As most components are manufactured in the factory, the quality, or rather high quality can be consistent and maintained as the working environment in a factory is easier to control. The wall surfaces, the soffit surfaces and so on can be controlled right to the millimetres in dimensions, hence improved and consistent quality. Another good point for buyers is... IBS allows projects to be completed faster than conventional systems - due to the introduction of pre-fabricated components to replace on-site works. Assuming there is a massive amount of quantity - economies of scale-wise, IBS systems will result in cheaper total construction costs, and buyers can benefit if the savings are transferred to them.
We have the yin.. how about the yang?
In most cases, there is a high initial capital costs for the contractors - which might decide to transfer the costs to the buyers. Plus, with only a handful of IBS players in the country, there is quite a 'monopoly' system. Further to that, the standardization of building components and elements also results in a lack of aesthetics value - buildings tend to be very boxy and square-y, which may not look as impressive as the conventional curvy buildings. But this part here - IBS systems are being expanded to be more architecturally and eye-pleasing.
The Singapore's HDB flats - which uses a lot of IBS elements - looks pretty boxy to me.
Another major problem... is when the contractors have bad workmanship while using pre-fabricated panels. This can result in problems in the joints - resulting in water leakages. In a country like Malaysia where it rains practically everyday, the problem can be very severe. To counter this problem - one has to thoroughly check through the completed units during handover to make sure the developer sorts out these defects.
Owner tries to hack a precast wall - only to find steel reinforcements which he has a dilemma whether to cut or not to cut. Cutting it might result in affecting the structural integrity of the building.
Another disadvantage with pre-cast elements is that these components are considered to be inflexible, with respect to changes/renovations. Most people would want to drill holes for wall lamps and so on - which is okay. But for some, they want to hack to allow for additional conduit works and wiring works - which might be a hindrance. If one buys two adjoining units, they may have problems trying to hack down some walls to allow two units to breakthrough.
