Initial situation
Since the 1970s, Germany has seen an increased application of External Thermal Insulation Composite Systems (ETICS) for the external insulation of buildings. With this method, insulation plates are directly glued or bolted to external building walls and then plastered. This significantly reduces the consumption of heating energy in both old and new buildings.

However, the dismantling of ETICS is disproportionally costly. Since the insulation material - polystyrene in 80% of the applications - is directly bonded to the wall and plastered, the classic dismantling methods consequently result in heavily mixed waste which is not recyclable and expensive to dispose of. There is the alternative to manually dismantle the ETICS; it can be removed and disposed of per layer with the help of various manual labour methods. This involves additional expense for the provision of scaffolding and personnel costs. Another option is to peel off ETICS together with their plaster layer using an excavator with a digging bucket. This method is significantly faster than any other manual method and only involves very little additional cost since dismantling projects generally require the deployment of large machinery.

In fact, excavator buckets can scrape off ETICS and thus separate insulation from outer building walls, however, there will still be material left on the walls. For this reason, the quality of the resulting construction waste is low and its impurities prevent re-use and optimal disposal. The disposal costs decrease with the degree of separation (up to 50% less per ton).

Research scope and objective
BaDA is a cooperative state funded project („Zentrales Innovationsprogramm Mittelstand - ZIM“) for the development of an innovative system to completely ablate ETICS on existing buildings. This new system is intended to provide a new standard to replace the common practice of using excavators with bucket diggers to scrape the material off walls. Within the scope of this project, an excavator attachment with quick-change system will be developed to allow for fast, economically feasible, and low-emission ETICS removal while providing a high degree of separation at the same time.

However, the basic idea of using a bucket digger will be maintained. The building walls will be machined with the help of a scrubbing drill attachment to remove plaster, insulation material, and adhesives. The brush head will be enclosed to retain dust and shavings and collect the material with the help of a suction system on-site. The separation and collection processes are not separated like in other common procedures.

The excavator attachment, which looks like a spoon, can easily and intuitively be used by any excavator operator. This new system’s planned working speed is comparable to the existing method, however, as a result, the outer building walls will be free from residues. Neither personnel nor machine cost will significantly increase, but the attainable degree of separation will substantially be improved and the waste disposal costs reduced.

WIMAG GmbH subproject: Concept, production, and testing of an innovative excavator attachment with variable housing and suction to remove ETICS in an emission-free, uniform, and targeted ablation process.

TMB subproject: Development of a tool prototype and test procedure incl. test rig for the experimental study of the process behaviour of machining tools when ablating ETICS.