Building

 

Client’s wishes :

The German satirical writer, Kurt Tucholsky, in 1927 summarized the wishes of a future house owner as follows 

 

In a slightly Americanized prose version, this could read as follows:

Wouldn’t This Be Loverly?

A country mansion with plenty of space,

the Pacific in front and Fifth Avenue behind,

with a nice view, rustic and fashionable,

the Rockies visible from the bathroom window,

not far to the movies in the evening,

the whole setup modest,

with nine rooms or, better, ten,

a rooftop garden with oak trees,

with radio, central heating, vacuum,

servants well oiled and keeping mum,

a sweet wife full of sprit and mettle

(plus one for the weekend and as a standby),

a library and, all around,

solitude and bumblebee humming. 

 

This kind of wishful thinking has not changed to this day. Unfortunately, such dreams fail not only because of the distance between the Pacific Ocean and a mountain top in the Rockies. The socially important need to “economize land use,” i.e. make sparing use of land, which cannot be augmented, results in current prices of developed sites between EUR 120 and 850/m2 in West Berlin, EUR 600 – 750/m2 in Munich, approx. EUR 500 m2 in Frankfurt, or approx. EUR 400/m2 in Karlsruhe. At an average price of EUR 280,000 for building a semidetached house in Karlsruhe, the dream of a ten-room house will fade very soon.  

Cost Percentages in Housing Constructtion:

 

Comparing the cost categories of houses built will show approx. 50% of the costs to be due to construction work. This cost share can be reduced by rationalizing in building construction 

 

 

 

 

Sources of Building Costs:

Comparisons of building costs reveal at once that cost savings are most likely to be achieved in erecting the building shell or, more precisely, in building the walls and floors and slabs. On the average, these items make up 43% of the building costs. The labor share in this category is 55%. Prefabrication allows labor costs to be reduced. As a consequence, building will be less expensive.

 

Trade	Percentage of building costs	Of this, labor costs in %
Groundwork, masonry work, concrete work	43,0	55
Carpentry	2,5	47
Roofing work	3,0	40
Plumber	1,5	35
Windows and doors	6,0	35
Heating	7,0	27
Sanitation system	5,0	42
Electrical installation	2,0	50
Screed	2,0	53
Flooring	4,0	55
Tile setting	1,8	36
Plasterer	10,0	30
Painting work	1,8	60
Locksmith's work	0,5	43
Cleaning	0,1	80
Other	9,8

Sites:

The percentage of cost due to the site is limited by the trend towards smaller sites. In some building areas, motor traffic consumes more than 30% of the area available. In agglomeration areas with high real estate prices it makes sense to design areas for traffic as well as garages and carports at basement level. The “top of the tunnel” may be partly planted, providing for sufficient public space for children to play and for communication among neighbors.  

 

Requirements to Be Met by Sustainable Houses :

Sustainability is often equated with the conservation of natural resources, such as soil and energy. Of course, modern housing concepts must save energy, i.e. have good thermal insulation. After demolition, building materials should be recyclable or at least easy to dispose of. Hence, designs employing thermal insulation only by means of thick layers of PU foam or mats of mineral fibers do offer benefits in terms of energy consumption, but are going to cause problems in disposal.  

Sustainability is owed to future generations. As political debates show, our present society is not organized along sustainable lines in social areas, such as pensions or the health service. The trend seems to be in favor of more self-responsibility. This could mean that the “agreement between generations” in future will have to be executed more often within families, with public opinion sharing this concept. This takes houses very different from the current semi-detached designs. In addition to children’s rooms, there should be rooms without barriers for grandparents. In order to allow more teleworking, houses need office rooms of sufficient dimensions. Returning to the times of our grandparents, when women stayed at home, provided for the family and raised the children, can be prevented by expanding existing service sectors, such as temporary day care and nurseries with flexible management models.  

 

 

 

Some Figures about the Building Industry:

The building industry in 1999 employed approx. 1.1 million people. This number is declining very strongly. While 603,000 residential units were completed during the 1995 boom period, it was only 230,000 in 2006. In East Germany, only 5000 flats in apartment houses were built in 2005. In 1997, it had been 99,000. In West Germany, the number declined from 186,000 to 56,000 over the same period of time. In West Germany, 99,000 single-family houses were completed in 2005, in East Germany it was 22,000. Investments into housing construction in 2005 amounted to DM 119 billion. Of this, 56% (65% in the East) were invested into existing housing, and 44% (35% in the East) into new buildings 

Cutting costs in the building trade by reducing the labor cost share in building construction is going to destroy jobs. However, there is no disputing the fact that ecologically required refurbishing of dwellings, and meeting the wishes of many families, constitutes a giant job potential. It is up to politics to offer tax incentives in support of refurbishing and new construction activities to such an extent that the number of jobs is maintained as a result of growing.  

 

Prefabrication of Construction Elements:

Making consistent use of modern planning techniques up to walking virtual models of a house creates the basis of highly automated factories for prefabricating structural elements for conversion and new construction. Unlike factories producing consumer goods, such as cars or white goods, factories prefabricating individual houses almost always make one-off products. Once all data are contained in a product model, work scheduling at the factory can access them and produce individual manufacturing documents at little expense.  

 

 

Factory for Wall Prefabrication:

Over the past couple of years, several brick laying robots have been developed which are able to erect walls of small bricks. An alternative to this technique are walls made up of large building blocks. Narrow elements as high as the room can be prefabricated very easily in a factory with a clearcut process flowsheet. A saw is used to cut modules into shape which cannot be installed the way they are made. A robot mills slots for wall installations. Two persons put installation elements, such as conduits for electrical installations or pipe coils for wall heaters, into these slots and apply a basic layer of plaster. The parts delivered in the correct  order can be assembled into a solid house on site in a matter of hours.