Assessing your own contribution to house construction correctly

Experts warn: Building owners should not overestimate the value of their own work. It is true that the so-called “muscle mortgage” can actually reduce construction costs – but only to a very limited extent. With some works there is even a risk of trouble with the law: What you should know about your own work in construction.

“Those who build by themselves need know-how and a lot of time,” warns architect Bernhard Riedl, building owner consultant at the Association of Private Building Owners (VPB). Many overestimate the value of their own work when calculating construction costs. That can take a bad revenge later and blow up the entire construction financing.

One can save so much by the own contribution

The VPB has calculated how much can be saved by the “muscle mortgage” for two regions: In the Munich area, a terraced house with three floors including a cellar and 140 square meters of living space, which costs around 254,000 euros, can save up to 19,000 euros.

Calculate the value of your own contribution

In order to determine the value of his own work, Axel Dr├╝ckler of the consumer advice centre Mecklenburg-Vorpommern advises to compare his own performance with that of a craftsman: “The tiler demands 5000 Euro. If there are 3000 Euro labour costs, I take them as a basis.”

Eva Reinhold-Postina prefers to consider the total expenditure: The saved working time for the specialist is compared with the costs incurred for journeys, material and equipment procurement as well as possible rental fees for tools.

Liability risks due to own contribution

For safety reasons you should leave your fingers completely off all work on the statics, as well as on the connections and lines for electricity and water. “If, for example, you lay the electrical lines in the house yourself and are not a qualified electrician, you have to reckon with trouble if a fire breaks out due to the lines laid by a layman,” warns the VPB.

“The insurance will probably not pay then. It is therefore better to leave such work to the specialist, which is even required by law in some cases – for example when installing a high-voltage connection.

Beware, moonlighting!

Whether a high proportion of own work makes sense also depends on who is to carry out the work. The law sets strict limits for the payment of helping friends and relatives. The threshold to undeclared work is quickly reached. “Already with 500 euro you are thick in it , warn the resident of Munich attorney Peter Oppler, chairman of the working group for building and real estate right in the German lawyer association.

For leniency owners cannot hope here – the treasury shows rather tendency to the severity than to the leniency , report Oppler from its experiences. In addition, private builders are generally obliged to insure their helpers against accidents. They also have to take care of occupational safety. Anyone who fails to do so can be punished and must be liable in the event of an accident.

Contributing to house construction on schedule

But it is not only uninsured construction workers who can get clients with a high proportion of their own work into trouble. A wide variety of trades are employed on a construction site. For example, the heating engineer can only install the new boiler once the screed has been professionally tiled. If the building owner does not perform his calculated own work on the agreed date or if his work shows defects, he can become liable for damages.

This can be expected “if I do things that influence other trades,” says legal expert Oppler. For example, if the tiler can only start work later or not at all due to a screed laid incorrectly or too late. Experts are obliged to check the performance of others before starting their work – even those that a private person has performed, explains the specialist lawyer.

Calculate the share of own work cautiously from the outset

The best thing to do is to keep your cool right from the start of the entire construction project, when you are still in the process of calculating all the construction costs, and do not calculate the proportion of your own work to be particularly high.

Most home builders overestimate their craftsmanship as well as their time and nervous strain. If then in the actual building phase the respective own contribution would have to be furnished, they either assign nevertheless the specialized craftsman. The following costs can easily blow up any construction financing.