Concrete Bases

As no site investigation data is currently available, formation soil is assumed to be compact natural sand, gravel or firm low shrinkage clay, below topsoil and fill material. Design bearing pressure is 100 kN/m2. Formation soil is to be free from roots and organic material, and all excavations are to be kept free from water during construction.
For foundations on medium and high shrinkage clays, loose granular soil, made ground, peaty soils and soft or very soft clay or silt, consult Hi-Tech Steel Buildings engineering department for further advice.
Where trees are present or have been recently removed within 25 metres of the building and the underlying soil is clay, please consult our office on the risk of shrinkage and swelling due to the moisture content changes in clay.

- Typically, concrete shall be designated mix RC28/35 as defined by BS 8500.
- Create a 150mm thick concrete slab with 1 layer of A252 mesh and 40mm cover of concrete.
- Create 150mm depth of compacted hardcore.


General Guidance on Slab Thickness:

100mm deep concrete base – where loads are very light and for domestic use only i.e. Garden sheds. 150mm deep concrete base – minimum in any commercial situation and suitable for the following,

- Shelving or pallet racking with a maximum leg load of 2.1 tonnes
- A mezzanine column with a maximum leg load of 4.7 tonnes
- Fork lifts with a maximum lifting capacity of 2.0 tonnes
- or uniformly distributed loads up to 70kN/m2

A deeper slab may be required where loadings are in excess of those stated above. Seek advice from our office or a competent Engineer.

Base frame Detail