A Tiny House can be extremely well built, designed to withstand heavy snow loads and strong winds, but if the foundation is not done properly, problems will eventually arise. The house may not collapse immediately, but it can start to sink or shift. This can lead to issues such as sticking doors, cracks in walls and a structure that slowly becomes uneven. Choosing the right type of foundation depends on several important factors, which are explained below.
The soil
Most people love pizza, but if the base is not good, the toppings cannot make up for it. The same applies to the foundation of a Tiny House. No matter how beautiful the house is, the soil underneath determines whether it will remain level and stable.
In the Netherlands, the most common soil types are sand, clay and peat. Sandy soil is generally the most stable and least prone to settlement. Clay soil has good load-bearing capacity, but it can expand and shrink due to changes in moisture. Peat soil is the most challenging: soft, compressible and highly sensitive to subsidence.
To gain certainty about soil conditions, a soil test (sounding or soil penetration test) can be carried out. This measures the strength of the different soil layers and identifies where load-bearing layers begin. While this may seem excessive for a Tiny House, it is strongly recommended for permanent locations or heavier buildings. Preventing settlement avoids damage and long-term uncertainty.
Your Tiny House and the duration of your location
A THOW (Tiny House On Wheels) weighing around 4 tonnes requires a different foundation approach than a 40 m² Tiny House placed permanently on a plot. The THOW of TinyFindy founder Marjolein Jonker, weighing approximately 3,500 kilos, stood in Alkmaar for five years on its wheels and wooden blocks on stable clay soil. After that period, the house could be relocated without issues.
However, this is not possible everywhere. The weight of the house and the soil type together determine whether concrete blocks are sufficient or whether a screw foundation is needed. The length of stay also plays an important role. For temporary locations of one or two years, investing in an expensive foundation is often not cost-effective. In such cases, lighter and more mobile Tiny Houses with simpler foundation solutions are usually chosen.
Common foundation types
Most Tiny Houses are placed on concrete blocks or on screw foundations.
Screw foundation
With a screw foundation, steel piles are screwed into the ground until they reach a load-bearing layer. A frame is then installed on top to support the house. Costs typically range between €5,000 and €10,000, depending on soil conditions and house size. Advantages include fast installation, minimal excavation and the possibility to remove the foundation later. This makes it a relatively circular and soil-friendly option.
Concrete slabs and blocks
Concrete slabs are often available second-hand at low cost, such as used “stelcon” slabs of approximately 2 x 2 metres for around €75 per piece. However, proper ground preparation is essential. The surface must be level and strong enough to carry the load. On sandy soil, the ground is usually levelled and compacted first. On clay soil, extra attention must be paid to drainage and stability. On peat soil, using concrete slabs is not recommended, as settlement is almost inevitable.
The trailer as a foundation
For a THOW, the trailer itself already forms an important part of the foundation. Nevertheless, it is advisable to partially relieve the load using adjustable supports or blocks. This reduces long-term stress on axles and tyres and improves overall stability. Especially for long-term placement, this is strongly recommended. It also helps to keep the house properly level, which significantly improves living comfort.
Other foundation options
In some cases, pier foundations, point foundations or strip foundations are used, particularly for permanent Tiny Houses. These methods resemble traditional construction techniques. While they offer less flexibility, they provide a very stable base.
Final thoughts
A good foundation often goes unnoticed — until something goes wrong. It determines whether a Tiny House remains comfortable to live in, whether doors and windows keep functioning properly and whether the house stays level in the long run. Taking the time to choose the right foundation and adapting it to the location, soil type and house design is essential. Every Tiny House deserves a solid base.
Images scre foundation by Chiela van Meerwijk
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