You can use your invoices with the detailed work to add to the value of the house. If the work was carried out in 2010 and had cost CHF 30,000, the depreciation linked to the past 10 years will have to be reduced again. Knowing that a house loses approximately 0.5% of its value each year, in 2020 the work loses 5% of its value, you will have to add CHF 28,500 to the price of the house instead of CHF 30,000.