For the layout of the building, provided that the ground characteristics allow it, we always use marking made with a topographic spray in fluorescent colours, because visibility of lines is better and precision is also considerably improved as compared to the traditional method using chalk.

At this stage we employ a qualified operator equipped with a self-levelling laser level so the excavation can be done at the desired height and completely level. Such operator is also in charge of checking that actual footings and beams agree to their specifications in the project at all times.

It is of common knowledge in this trade that iron deteriorates along years if directly in contact with ground, stone and gravel.
For this reason and as provided by current laws on building regulations it is necessary to use blinding concrete under reinforcement. A layer of approximately 5 cm is generally recommended.

Due to changes in regulations mainly introduced for increasingly demanding quality control, the footing dimensions are larger and larger, which determines both the gauge and length of corrugated iron or steel to be used, and in many cases it is necessary to use a mobile crane to put it into place.
In this way labour costs are significantly reduced and economic impact on the client is much lower.

To level the base plates in respect of the same height, we use the self-levelling laser lever, so all slabs can be level no matter how large the building dimensions are.
Likewise, to level the slab itself, two magnetic levels are used as shown in the photograph so that the slab is completely level in both directions X and Y.

We employ our own personal method devised after many years of work in this trade, which makes our task considerably easier. Such method can be summarised in three points:
1. Use of an extensible straightedge that can be regulated in height and which is welded to the mesh in the base plate to prevent any displacements.
2. Once the base plate has been placed on it we fix the plate by welding.
3. By means of 16-mm diameter corrugated steel re-bars the base plate remains perfectly welded to the mesh and it cannot be displaced at all when pouring the concrete.

Before pouring the foundation material we surround the perimeter of the premises with a 35 mm naked copper wire as ground connection, located on the beams. We even place a 100-cm pick and cable clips for a better hold of the wire.
We currently use HA-25/A/20 Amb/IIa. Without any doubt we will proceed to vibrate the concrete in order to get an homogeneous texture, insisting particularly at the foot of the base plates.
So that the prefabricated walls can be perfectly based on the concrete of the beams, we level it between each two base plates using a straightedge that must be long enough.
To round off our work, we will proceed to clean any possible concrete stains on the base plates.