Garden house - plan and build the foundation

Garden house - plan and build the foundation

the essentials in brief

  • For a garden shed (€ 7.70 at Amazon *), different types of foundations are possible, e.g. slab foundation, punk foundation, strip foundation or concrete foundation
  • As an alternative to the concrete foundation, drive-in sleeves, plastic, wood or metal substructures can also be used
  • A concrete foundation costs around 30 euros per square meter
  • Old pavement slabs are an inexpensive and durable option for the garden shed foundation

Required material

The material depends on which foundation you choose. In order to save costs and reduce the workload, you can fall back on alternatives. However, thorough planning is crucial for the choice of the foundation, because the load-bearing capacity differs greatly.

also read

  • Erect a point foundation for the garden house
  • The right foundation for the garden house
  • Foundation and flooring for a garden house without a floor

Typical foundations:

  • Slab foundation : gravel and fine sand, paving slabs
  • Point foundation : formwork, concrete, concrete anchors
  • Strip foundation : shuttering, concrete, concrete anchors, possibly gravel
  • Concrete foundation : reinforcing steel, shuttering boards, concrete, gravel

Alternatives to the solid foundation

It is possible to build a foundation without concrete and slabs. You can fall back on prefabricated constructions made of plastic or metal, or design the foundation more individually with punctiform alternatives. With the wooden foundation, you must ensure that the beams must not come into direct contact with the ground.

fitnessadvantage
Drive-in sleeveslight to medium garden houseseasy compensation of uneven floors
plasticLightweight constructionseasy to use
Woodmedium-weight garden housesecological and inexpensive
metalheavy garden housesexpandable, change of location possible

planning

garden shed foundation

If you are using a simple foundation made of drive-in sleeves or plastic, thorough preliminary planning is less important. If you want to set up your garden house on a concrete foundation, the planning becomes an important part. You can make a simple sketch using pen and paper. It gets more professional with a computerized plan that gives you more flexibility.

SketchUp

With this software you can create simple two-dimensional or clear three-dimensional plans. The basic version is free and offers you various tools for planning. Here you can build the foundation true to scale so that you can identify and correct potential weak points. Such a plan makes sense for a foundation made of paving slabs, which are to be laid precisely and without cutting.

Thorough planning is also important for the foundation. The free basic version of SketchUp is a perfect tool.

costs

The most durable variants, which are characterized by high stability, are concrete slabs and strip foundations. For the material costs you should estimate around 30 euros per square meter, although the price can vary greatly depending on the source of supply. If you are paving a foundation made of stones or paving slabs, you can expect ten to 15 euros per square meter for inexpensive variants. If you have the foundation built, the costs will be more than 100 euros per square meter.

Calculation example

There are various companies that offer a full service. At Mein-Gartenshop24 you can get a small garden shed from Karibu with a floor space of around 180 x 120 centimeters and a towing roof including foundation and on-site assembly from around 1,800 euros. The shed is positioned on drive sleeves and can be painted with wood sealing or varnish if desired. Individual requests are specified when booking online.

How do I build a foundation for a garden shed?

If you want to build your garden house yourself, you can also create the required foundation yourself. Calculate beforehand the load that must be supported by the foundation. You can then decide on a variant.

Pavement slabs for sheds

garden shed foundation

The simplest solution for a quick foundation are disused sidewalk slabs measuring 30 x 30 centimeters. These can absorb flat loads of 90 kilograms per square meter. Since they cannot withstand punctual forces, paving slabs are only suitable as a base for light tool sheds or small greenhouses. (€ 34.95 at Amazon *)

Instructions for building:

  1. Dig the ground 20 centimeters deep
  2. Fill the area with gravel and compact
  3. fill up fine grit or sand
  4. smooth with a peel board
  5. Lay out paving slabs and fill the joints with sand

Pave the foundation

If you have paving stones left over from sidewalks or driveways, you can use these as a foundation for your garden shed as well. The load-bearing capacity is comparable to that of paving slabs. The construction process is similar. The foundation can be delimited by lawn edging stones.

  • Roughly stake out the area with wood
  • Dig about 25 deep and ten centimeters wider than the base
  • Compact the soil well with a vibrating plate (€ 214.60 at Amazon *)
  • Align the batter board
  • Place curbs on concrete and allow to harden
  • Fill the area with gravel or crushed stone and straighten it
  • Spread fine-grain sand
  • Lay paving stones with the same joint width
  • Compress the joints with sand
Youtube

Point foundations for small to medium-sized garden houses

Small and medium-sized garden houses find stable support on point foundations. The load is distributed over many individual foundations that lie under the load-bearing beams. The difficulty with construction is that all foundation points are at the same height and must be precisely aligned.

To do this, the ground is leveled and the individual points are marked with a wall cord. Holes with a depth of 80 centimeters and a width of 20 centimeters are dug at regular intervals. After the concrete has been poured and hardened, the garden shed beams are fixed with concrete anchors.

Tips

If the soil is very loose, then formwork will be needed. You can use shuttering blocks or thick KG pipes for this.

Strip foundation for large garden houses

garden shed foundation

With this variant, the sub-floor must be stable. The weight of the summer house is distributed on a 30 centimeter wide concrete strip that runs under the load-bearing walls. The strip foundation can be stabilized with an additional concrete slab. If no concrete slab is used, the area should be filled with gravel or paved.

Make strip foundation yourself:

  • Mark the outlines of the garden shed with stakes
  • Mark load-bearing walls
  • Excavate strips 80 centimeters deep and 30 centimeters wide
  • Board walls
  • Concrete trench

background

Why strip foundations have to be so deep

The soil temperature in Central Europe does not drop below freezing point at a soil depth of 80 centimeters even in the icy winter months. If the foundation strip extends to this depth, the dreaded frost stroke is avoided. When water collects and freezes under the foundation, it is raised under high pressure. Cracks in the foundation and masonry are inevitable.

Slab foundation made of concrete

A solid concrete foundation should be built on very sandy or swampy soils near water bodies that do not have a high load-bearing capacity. To protect against rising damp, the subsurface is covered with a compacted layer of gravel on which a PE film is spread. High point or surface loads are optimally distributed over the entire floor slab.

building instructions

The area is excavated 30 to 40 centimeters deep, with the pit being slightly larger than the dimensions of the floor slab. This space will be used later for the casing. Level the soil in the pit and compact it with a vibrator. The edges are lined with sturdy cladding boards that fit exactly with the surface of the concrete slab.

  • Fill in a 15 cm thick layer of crushed stone or gravel and compact it
  • Check the surface with a spirit level and smooth if necessary
  • seal with PE film
  • Fill concrete five centimeters high
  • Lay out reinforcement mesh
  • fill another ten centimeters with concrete
  • lay out second reinforcement mesh
  • Fill the formwork completely with concrete and then smooth it out

Tips

The reinforcement mat protects against cracking in the concrete. To further increase stability, you should compact the concrete before leveling it.

frequently asked Questions

What does a foundation for a garden house cost?

Depending on the type of foundation, the costs vary greatly. If you have a company build a foundation, the costs quickly rise to over 100 euros per square meter. It will be cheaper if you take over the construction work yourself. For the production of a continuous concrete slab, you have to reckon with around 30 euros per square meter. If you use individual pavement slabs as a substrate, which are laid on a bed of sand, the costs amount to around ten to 15 euros per square meter.

Do you need a foundation?

A foundation ensures stability and ensures that the wood does not come into contact with the ground. If the garden house is standing directly on the ground, rain, snow and temperature fluctuations can cause long-term damage. The soil moves over the course of the year, so walls can warp or cracks appear. A garden house without a foundation is not recommended. It has no base that distributes the loads evenly. The garden shed can sink at certain points if the soil has different properties.

Do I need a permit to build a foundation?

In principle, garden houses that are freely placed on the meadow without a foundation do not require a building permit. They must not be higher than 250 centimeters and not exceed an area of ​​300 x 400 centimeters or 10 square meters. As soon as the garden shed is to be placed on a foundation, you must inform yourself about the applicable regulations at the responsible building authority. The municipalities decide on the need for a building permit and refer to the state building regulations of the respective federal state.

Are there alternatives to the foundation?

A small garden shed can also be placed on a simple foundation made of cobblestones, provided the subsoil has been removed beforehand and filled with gravel. If the load is not particularly high, you can fix the garden shed on a structure made of wood, which is supported by several point foundations. This means that the wood does not lie on the floor. A quick foundation for the wooden lattice can also be built entirely without concrete. As point foundations, you can use square and superficially grooved stones, which are fixed with mortar.