Bakau Rules the Day

the architect's vision

Originally, the 3-storey extension at the back of the house was to sit on a foundation of concrete piles. But we switched to using bakau piles after discovering there was only one piling contractor in all of Malaysia with equipment compact enough to enter the site. He was going to charge me over 3x the normal mobilisation cost, probably because he had a monopoly on the market. I wasn't about to spend the amount he wanted, which was almost a quarter of my budget. So, bakau piles it had to be.

bakau standing by

It turns out that bakau wood is an extremely suitable piling material for the soil conditions at Malay Street, and has been traditionally used in the area as a material for laying building foundations. As the area was reclaimed from what was originally a swamp, the water table is very high. This allowed the piles to be perpetually immersed in water - a pre-requisite condition for ensuring bakau - or mangrove - doesn't rot. Also, the 'soil', being composed of marine clay made it easy to drive the piles in using only a backhoe.

the backhoe, ready to go

I learned that bakau piles are called "friction piles" because the piles are suspended in the clay by friction between the pile and the surrounding clay - rather than resting on rock or a hard surface at the bottom. Its as if the clay were gripping the piles like a hand would.

bakau piles for one column, ready for capping

This would work out well. Except that the weight of the building had to be reduced. So, we scrapped the green roof and changed the concrete stairs at the back to one of steel.

pouring concrete to cap the pile