Easy and durable: modernising! A shaft-in-shaft modernisation is the simpler, faster and above all a more long-lasting solution to the problem. The core idea is to insert a new AWASCHACHT of the next smaller nominal diameter into the old, corroded shaft. The old shaft remains in the groundas permanent formwork. The result of the shaft-in-shaft modernisation is a new, sealed and structurally sound shaft with a service life of up to 100 years!