keeping out about 90 percent of the heat in summer the house was built by construction company owner heiko schultz for more than 25 years he's been building have to bring houses based on old designs but with the latest technology inside. it's a real challenge people used to build very differently centuries no one was concerned with energy efficiency and cetera these days we have to work with significantly thicker walls and accommodate very different things windows have to be fitted completely differently and it all has to be done so that it's not visible outside. the wooden skeleton is constructed in a carpenter's workshop using only timber grown in europe spruce fur large douglas fir or oak. just as in olden times no nails are used. instead the beams are connected with joints secured with opec's in keeping with traditional methods. this is a joint that has been used by carpenters for centuries only wood is used. the advantage is that it expands in the same way when temperatures fluctuate that's not the case if you use wood together with metal and that can cause damage in the long term a joint tha