Almondia – Bautipps Die Bauherrenberatung

Shell house: how long does it take to build?

Imagine you are celebrating the topping-out of your new house with your friends over a glass of sparkling wine. You have already covered a large part of the way on the way to the finished home. But how long does it take to complete the shell of the house and how many trades does it take to finish the shell? Which decisions have to be made? In this article we would like to take up the most important questions about the topic of shell construction and provide answers.

the essentials in brief

  • The shell designates a new building whose foundation, outer and load-bearing walls and roof construction have been completed.
  • The shell construction work should not begin or take place in winter, as this entails risks for the building fabric. If this cannot be avoided, the construction company must prepare the construction site.
  • The shell construction takes about 3 weeks. What all belongs to shell construction, is explained in the following article. After the shell you should allow about 7 months to complete the house.

What does the shell of the house include?

After the complete planning has been carried out down to the last detail, the construction project has been approved by the authorities and the contract documents with the construction company have been signed and clarified, the shell construction can now begin. But builders often ask themselves which services actually belong to the shell construction. A precise definition for the construction phase of the shell is not that easy.

The shell designates a new building whose foundation, outer and load-bearing walls and roof construction have been completed.

When comparing construction companies and their offers, builders occasionally come across terms such as “closed shell” or “finished shell” . Caution is advised here. Often such terms hide pure sales vocabulary and an unjustified surcharge for individual services that the client in question could provide himself or must already take into account when choosing the expansion stage. An independent review of the offer is always recommended.

The client must agree in advance with the developer on the appropriate materials, trades and stones . The flexibility of the construction companies and the possibility of responding to the individual wishes of the builder also depends on whether the interested party has opted for a prefabricated house or a solid house . Both construction methods have their advantages and the decision is now a question of taste and less a question of quality.

Shell house – step by step

The coordination with the developers is done. Now the shell construction can begin. The following steps are necessary for this.

Shell house step by step

Construction site equipment and earthworks
foundation and floor slab
Preparation of connection to supply and disposal
walls and roof

1. Site setup & earthworks

Construction begins and the site is set up . All necessary construction equipment, machines and materials such as excavators, cranes and cement are delivered. First earthworks are carried out. The topsoil is removed and in some cases stored for later steps.

2. Foundation

The next step is the foundation excavation and further work for the erection of the floor slab. Depending on the requirements of the substrate, the depth, the type of insulation and the built-in parts, such as pipe penetrations, can vary. When excavating the foundation, it should also be noted that the prices per cubic meter removed depend on the soil class. This means that, for example, an excavation with rock that is difficult to remove can cost ten times the price per cubic meter for topsoil. First, the developer sets up a so-called blinding layer of at least 5cm, mostly using gravel as the material to keep moisture away from the floor slab. The respective construction company creates additional insulation using PVC or PE foils. The next step is pouring the bottom plate. This consists of concrete, which must not dry too quickly after pouring, otherwise cracks may appear.

The floor class

The soil class determines the price per removed cubic meter. Before every construction project, the construction company carrying out the work requests a so-called subsoil report, which provides information about the composition of the subsoil and its load-bearing capacity. There is also information about the soil class: is it normal topsoil, clay soil, rocky subsoil or other components? The subsoil report is usually provided by the client via a geologist.

3. Supply and disposal lines, necessary shafts

Depending on the building permit, the construction company lays the sewage pipes and other shafts for disposal and supply lines. However, the correct connection is usually only made after further construction phases have been completed.

4. Structure & Roof

Next, the load-bearing masonry of the ground floor is built onto the dried floor slab. All necessary openings and details for windows etc. must be taken into account. In the case of a prefabricated house, finished complete walls with windows and shutters already installed are often delivered, erected and assembled.

The ceiling and all the necessary elements are then installed. The roof truss is then erected and anchored according to plan. If the house was planned with a chimney, the chimney or a prefabricated chimney is installed according to the regulations and the roof construction can begin. This means that the formwork, insulation and sealing of the roof now follows.

How long does the shell construction take?

The time it takes to complete the shell house depends on whether the builders have opted for a solid house or a prefabricated house. A prefabricated house is often erected within a day, since the prefabricated parts only have to be assembled. For a solid house, the process takes about 3 weeks on average. In the meantime, however, there are also mixed forms between solid and prefabricated houses. Such “massive prefabricated houses” usually have a short shell construction phase.

When should the structural work begin?

The timing of the structural work is at least as important as the duration. If the shell is not sufficiently dry and is unheated and partly exposed to the adversities of winter, this can lead to long-term damage to the building fabric. The water contained in the building materials can expand during frost and cause cracks. If the construction of the house does not start until late autumn, in the worst case the shell must be left without a roof because the weather does not allow work to continue. This allows rain and snow to enter the house without restriction.

Shell construction in model house settlement
The shell is complete ©2020 Kemb GmbH

Adequate preparations must be made before the start of winter, e.g. closing the shell, preheating with electric heaters or covering the masonry with foil (in the case of an open shell). The rule is: better safe than sorry. It is better to start building early enough so that seasonal weather conditions are not an enemy of builders.

What comes after the shell?

Once the shell has been completed and the topping-out ceremony celebrated, the next step is the interior work. The interior design of a house includes screed work, door and window installations, painting work and the installation of sanitary facilities. In the case of very damp screed in particular, it is extremely important that it is given enough time to dry. Coordination is essential here. If the screed work is postponed for a variety of reasons, but the follow-up appointments for floor work follow the original schedule, then floor coverings on damp screed can lead to damage to the house. In some cases, the screed has to dry for up to two months, otherwise mold can develop in the house, a typical consequence of botched construction.

How long does it take from shell construction to moving in?

This question is relatively difficult to answer and depends on many things, such as the coordination of all those involved in the construction, the individual services taken on by the client, the agreed expansion stage (turnkey or ready for expansion, etc.), the weather and the season. Here, seven months is usually the rule.

Whether you decide on a prefabricated house or a solid house, the shell construction is the biggest step towards owning your own home. Find a construction company that you feel comfortable with and that fits your needs from the start to be in good hands with this step.

Autorin Sarah Völkl

Sarah Völkl hat Architektur studiert und ist seit Jahren das Gesicht von a better place. Mit ihren Videos ist sie bei YouTube vielen Personen schon länger bekannt. Sarah teilt Ihr Wissen jetzt auch bei den Bautipps von Almondia.

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