I read the many posts here with great interest. We were about 3% under budget. We still had 7 K Euro left for an additional terrace roof and the generous roofing of the entrance area. The whole thing was very thoroughly planned in Excel and each item was tracked in a target/actual comparison. That way I immediately knew if something was getting out of hand. In case of deviations, we inquired further and usually found a cheaper provider. Or increased the share of own work. Planned was completely without own work. Only painting work for 1500 Euro material. (for 84 m² living space). Regarding the additional costs: Floor slab: 18,000 House: 135,000 ("schlüsselfertig") Plot: 70,000 Additional costs: 19,000 Double carport 9 x 7 m: 6000 (material, own work) Outdoor area: 10,000 (material, labor in own work for paving driveway and terrace)