For a new zero-energy housing concept, EGM architects worked with NETICS on the development of a facade composed of blocks made of compressed dredging sludge. Featuring their own surface print, they can give a project a distinct look.
Technical designer Hans van Pelt is very proud that EGM is introducing the sludge block into housing construction. Last summer the architecture firm took part in a competition for a facade concept. Van Pelt: “The commission for entrants was mainly to think out of the box. Nothing was too crazy. The first thing we did was to dip into architectural history to see what consumers find beautiful. The Amsterdam School style turned out to be the most timeless. That’s why it was taken as the source of inspiration but given a contemporary twist.”
During the quest, Van Pelt came across dredging sludge as a replacement for brick. Van Pelt: “We spoke to Netics, an engineering firm in Alblasserdam that processes dredging sludge. From that material they compress large blocks that measure 100x100x50 cm in size and use these for, among other things, dike reinforcement, naturally embanked watercourses and breakwaters. We asked Netics if they could also compress a small block, and they did just that.”
In the past, making blocks from dredging sludge was hampered by the slow combustion process and high energy consumption, so a different procedure was used this time. Van Pelt: “The blocks are compressed under such high pressure that the material hardens into stone that is as strong as sand-lime brick. Its structure is also similar, except much finer.”
The basic ingredient is dredging sludge, which is filtered to remove small twigs, valve caps and other waste. “Then a mineral adjuvant is added before the mixture is compressed. The method means that dredging, filtering and processing can be done on site. All you need to do is transport a compressing machine to the site where the sludge is dredged.”
Soon clients can choose from various reliefs and formats for blocks made of sludge. Van Pelt: “Lots of individual creations are possible. Buyers can therefore leave their mark on the house, while using the material ensures unity in facade composition.”
The idea phase has more or less concluded now, explains Van Pelt. “The big blocks have been tested and developed together with TNO. The small block is a derivitave of it. Now we’ve reached the moment to introduce our idea on the market, so we’re looking to collaborate with project developers and estate agents. We’ve open to ideas.”
The question is whether the Royal Dutch Building Ceramics will welcome this development. Van Pelt: “Major brick suppliers will no doubt be sceptical initially, but they will have to embrace an innovation like this. These are new times. I expect that the people in Alblasserdam will soon be very busy.”
Cobouw, the newspaper for the construction sector, published an extensive interview with Hans van Pelthenen concerning the development of the facade block made of dredging sludge.