Crazy paving
[Column]
It happened so gradually that I hardly noticed, until a visitor pointed it out to me. “Your paving slabs are in a bit of a state. Subsidence?” I suddenly saw my front garden through his eyes and he was right, it was turning into an obstacle course of uneven slabs.
Heel Holland Zakt was the title of an article on subsidence written a couple of years ago by science journalist René Didde for de Volkskrant newspaper, about the ground beneath our feet. An article with a sobering message. The wettest areas of the Netherlands will sink by up to 84 cm this century; the land is sinking faster than the sea level is rising.
Peat oxidises and reduces in volume when exposed to air. This can be prevented by having a higher water table, but the farmers don’t want this, because if their meadows get too waterlogged, their tractors get stuck in the mud. So the water table is kept low and the land continues to sink, which, in addition to peat oxidisation, leads to extra greenhouse gas emissions.
In Heel Holland Zakt , experts came up with all kinds of creative solutions, from lightweight cattle which cause less soil compaction, to floating housing estates. We urgently need to think outside the box, but the question is whether the proposed innovations will be in time.
It has been remarkably dry in the Netherlands for a considerable time, resulting in a low water table and extra subsidence problems. The KCAF, a knowledge centre for building foundation problems, warned this year that one million houses are under threat.
According to a report by RTL Nieuws news channel, houses built before 1970 are particularly at risk: one in four faces potential subsidence. The cost for home owners can be as much as 100,000 euros.
I think my house was built before 1970. I know I don't have 100,000 euros to spare. And my paving slabs are uneven.
On the way to the builders merchants for some sharp sand to level things out again, I tried to stay calm. Of course the KCAF would say there are huge foundation problems; it’s in the interests of any knowledge centre to give extra emphasis to its own specialist problem area. Just imagine the knowledge centre for foundations saying ‘subsidence, no problem, these foundations are fine for another hundred years’; they would put themselves out of a job right away.
Anyway Mudde, don’t get all worked up! - uneven paving slabs don’t mean there’s something wrong with your house. The house is built on piles, there are no cracks in the walls and all the doors and windows open and shut smoothly.
Back from the builders merchants, I lift the paving slabs one by one, spread and compact the sharp sand and replace the slabs.
A job well done - as smooth as a billiard table. For the time being, because there’s something going on underneath those slabs that no-one can stop...
