House building / solid house: The house building on a property in slope situation is not so unusual, as it seems at first sight. In some areas it is normal to build on a sloping site. In some places such properties are particularly desired and accordingly expensive, as for example in Hamburg Blankenese, where alone the (unobstructable) view of the Elbe constitutes a large part of the property value.
A house on a slope can offer a special quality of living, but this also requires a suitably motivated building planner, because in terms of planning there are usually special requirements and other framework conditions to be taken into account. Only with a clean construction planning from the beginning, mistakes and thus additional costs can be avoided when building a house on a slope. Hillside houses are usually built with several floors, which requires special measures in terms of barrier-free construction.
In principle, the slope of a plot of land is not an obstacle to building a house if the motto "work with the slope" is followed during construction planning and the slope is not resisted.
The special advantages for building on a slope are made clear in the following video.
The main "sticking points" of building a house on a slope are explained in particular below and are in alphabetical order:
Orientation (north slope, south slope)
Construction methods (stilted construction, split-level construction)
Geological conditions (soil expertise)
The orientation of the hillside house
The orientation of the plot is considerably more important for building a house on a slope than for a plot on a flat surface. The steeper the slope, the greater the demands on the designer, because the technical requirements change with each degree of incline.
Now what is the best location for a house on a slope?
A south-facing slope with large panoramic windows allows the building to be optimally opened to the sun and thus also to use solar energy. Houses at north slopes against it lead frequently in the wahrsten sense of the word a shade existence. A house on a north-facing slope has to cope with the shading of large areas, so a lot of emphasis has to be placed on large glass areas.
For properties facing east or west, you usually have to give up the evening sun or the morning sun. In this case it is advisable to work with balconies resp. To arrange projections and recesses, at least in part, a reasonable illumination of the house.
Before you start to buy a building plot on a slope, you should visit the plot at different times of the day in order to be able to assess the respective sunlight more precisely.
So, important for the assessment of the quality of the building plot are mainly the requirements for houses on a north slope and houses on a south slope.
House building on a north-facing slope
The problem with building a house on a north-facing slope is that the planned new building will be shaded to a greater or lesser extent. With the considerations to the property purchase it should be clarified therefore also whether above the planned own house still further buildings are established, which would increase the anyway existing shade disadvantages further. In the winter time, the shadows become longer and longer, so that the sunlight and natural lighting would be endangered and affected by additional buildings. Of course, one must then also reckon with additional costs for heating, windows and lighting. Also the use of solar energy is not or only very limited possible with a north slope property.
Building a house on a south slope
When building a house on a south-facing slope, the conditions for optimal living are ideal. The slope protects the building from adverse weather conditions towards the north. If the house is then cleverly placed, it can be practically packed into the terrain. The conditions of the solar use are then optimal, both passively by the solar irradiation over the large window fronts, and actively by solar plants. However, special heat protection measures may be required in summer.
A hillside house is not the best candidate for barrier-free building and living, however, by taking appropriate measures, it is certainly possible to build a hillside house barrier-free. In any case, this requires a stair lift or even an elevator that connects the individual floors and the entrance and garden area with each other.
Construction methods for the house on the slope
The orientation and even more the degree of inclination of the slope is decisive for which construction method should be used. There are three architectural variants for the construction of the hillside house.
The first and most common method of construction is similar to building a house with a basement on a flat plot of land. However, the basement is built as far as necessary into the slope. The rear part of the basement is then also windowless, while the front area can be used normally. The house itself is then built on the basement level.
As a second variant, the stilted building is very often used. In this method of construction for the hillside house is built virtually on stilts. The house on stilts is used for particularly steep slopes and for subsoils that are difficult to work on. The house itself floats above the plot. The connection between the house and the plot must be found for the house entrance with architectural solutions.
The last variant in the construction method is a so-called "split-level" construction. This is certainly the most complex way to build a house on a slope in terms of construction technology. Visually, the individual rooms follow the sloping elevation of the terrain. In this way, mezzanines are created, but they also have the disadvantage that you have to climb a lot more stairs.
Energy concept for a house on a slope
For a positive energy balance of the hillside house provides especially a house that is built on a southern slope. If the house is built into the slope, natural insulation is created on the building envelope facing the slope. This natural thermal insulation already contributes significantly to a positive energy balance.
Through solar systems, both solar thermal systems and photovoltaic systems, additional energy can be saved and the hillside house can then be brought with little additional effort to the level of K houses or even a passive house. K standard is automatically associated with the entitlement to a substantial public subsidy for the building project from the K bank.
It is in the nature of things that the development of a hillside property is associated with more circumstances and special features than a "normal" property. Prime examples of this are site equipment and the site access road. With steep driveways, the use of heavy equipment is sometimes not feasible, or only at great expense. If the plot is in a particularly rocky area, it is also difficult to lay the utility connections for electricity, water, gas, telephone, internet and, if necessary, cable television.
Foundation and structure
The main problem in the static calculation of the foundation and the building itself is the slope, which gives rise to special loads and must prevent the building from slipping down. Under certain circumstances, retaining walls and reinforcements must be used to support the bearing capacity of the subsoil for a solid house. In the most common variant of construction "into the slope", attention must be paid to the earth pressure and the foundation must be adjusted accordingly. In order to be able to absorb these loads, driven piles, concrete bases and various reinforcements are used.
When building on stilts, the concrete stilts must be placed on a concrete foundation that can withstand all wind speeds and other expected weather conditions.
Geological conditions must be explored, a soil survey is therefore urgently required
When building on sloping land, great attention must be paid to the geological conditions that prevail on the site. The soil conditions of the building plot must therefore always be checked, so that at some point the building does not actually go downhill. For this purpose, a soil expertise is required, which can provide exhaustive information about the load-bearing capacity of the soil and in the context of which it is determined whether the property is at all suitable for building a residential building. In addition to the findings on the load-bearing capacity of the soil, information on its stability against slipping and any water-bearing layers also play an important role.
It is therefore essential that the soil expertise contains statements about
the nature of the building site
the load-bearing capacity of the soil and its stability against slippage
Existing water-bearing strata
Existing slope water
The term slope water refers to a special form of stratum water, which usually occurs during precipitation. This water accumulates in front of the exterior walls of the building on the slope and thus creates hydrostatic pressure, which allows the water pressing from the outside to penetrate the masonry and thus damage it.
As a protection against the penetrating water, construction waterproofing and drainage pipes are used to drain the water away. The DIN regulations (DIN 18195) for the protection of structures against moisture and water must therefore be taken into account during construction planning.
Cellar, a must for every house built on a slope
Slope houses usually have a basement, although not a classic one, which protrudes from the ground on one side, because in the basement the planned living spaces are on the valley side, while the ancillary and technical rooms are on the slope side. The basement or parts of it are also very suitable for a granny annexe with its own access, a garage or a garden level.
The cost of building a house on a slope is not necessarily higher than for a conventional plot of land. There are alternatives, with which purchase and development of a slope property can turn out even more favorably.
The property itself may be more cost effective, as hillside properties are not necessarily popular with buyers, depending on their location. If a basement has to be placed only halay into the slope, the costs are lower than for an extra dug complete basement excavation.
Additional costs can undoubtedly arise in the context of the construction site equipment, the development and the construction itself. If measures to secure the property against slipping become necessary and the drainage of the slope water requires additional measures, additional costs will also be incurred.
Those who build a house on a slope will be compensated for their efforts and costs with much more quality of life and an invaluable and priceless view.