Groundworks and excavation   

                      Building/Groundworks and Civil-engineering  

                                             Concrete floor plan details

I imagine that the building the floor is one of the most complicated and one of the hardest jobs to be undertaken in the construction of the extension as there are so many layers to the job!

The drawing below shows what has to be laid down and in what order.


                                                                          All the layers that form the floor

From the bottom up...

  • The hard-core base that will need to be consolidated with a vibrator and be at least 100mm thick.

  • A thin layer of sand to protect the damp proof membrane from being damaged

  • The damp proof membrane usually 1200g polythene (shown thicker here so that it can be seen)

  • The 80mm thick phenolic or polyurethane insulation layer

  • The 100mm concrete slab that might need to be reinforced if the floor is large

  • The final screed to provide a flat finish

  • The final floor - tiles for me.

                                                                                 The damp proof membrane shown in red

The above diagram shows the damp proof membrane in red (and thicker than it is in real life) and shows how it folds over the DPC material in the wall to form a complete watertight seal.

                                                                                        The thicknesses of the individual layers

The above diagram shows the thicknesses of the individual layers which vary around the country so it's worth checking with your local planning control officer.