We excavated the trenches to just over a 1000mm down ensuring that we had a suitable strata to pour the concrete on. We hit clay at around 5oomm down so continued the excavation until we were at a good virgin soil. The BCO will normally ask for an excavation to 900mm down but in our case between 1000 to 1100mm was nearer the mark.
Once the excavation had been passed by the BCO, it was time to start pouring the concrete. Prior to pouring we will have set up our depth pins, levels, shuttering and anything else necessary to help us prepare for the building after the concrete pour. By checking levels at this stage and setting the concrete to coincide to let’s say the DPC level, we can easily gauge courses to help us achieve accurate levels or datums for when we get out of the ground. We will have set out all of our levels with either a theodolite or a rotary laser level.
Please also note that it is vital in the setting out stage to ensure things are all square and the building lines are where they should be. It would be incredibly expensive, if not near impossible to have to change things around if they haven’t been worked out correctly beforehand! Many extensions by inexperienced builders or builders who just don’t pay enough attention to their work have ‘Gone South’ from a lack or proper planning techniques.
Here’s the concrete.