Tutor transferring levels
- 2. Reasons for Transferring Levels There are a number or reasons for the transfer of levels in substructure work. These include: • To establish the level of the ground for excavation (both oversite and trenches). • To ensure materials such as concrete and hardcore are laid to an accurate level. • To establish datum for bricklaying, e.g. DPC level. • To establish a level for concrete formwork, e.g. when constructing a concrete raft foundation.
- 3. Transferring Levels from the Datum to the Foundation (Strip) During the process of setting out, a datum peg is positioned to mark a predetermined level, such as DPC or floor level, this is called a Temporary Bench Mark (TBM) This is the level from which the bricklayer or ground worker will transfer levels helping to control the depth of the foundations and brick footings.
- 4. Datum Peg Spirit level and straight edge Gauge Rod or tape measure Concrete thickness pegConcrete thickness Multiple of brick courses Transferring Levels from the Datum to the Foundation (Strip)
- 5. Having set the first peg to gauge from the datum, the level must be transferred all around the building’s foundation to provide a guide for the top of the concrete when poured. Optical or laser levels are most commonly used to do this. However, at times the, bricklayer will find it more convenient to simply transfer the levels around the trench by the use of a straightedge and spirit level.
- 6. Using a Straight Edge and Spirit level It is essential to REVERSE the level and straightedge at each peg reading. This ensures that any discrepancy in the straightedge or level is not repeated at every peg, but cancelled out at every other reading. Datum peg Depth to work brick courses Spirit level and straight edge
- 7. Boning Rods Another method of transferring levels around a trench is by the use of boning rods. Boning rods are made from timber and are usually painted so that they are easily seen. Boning rods are typically used in threes, the middle one being known as the ‘traveller’. Boning Rods Traveller Levelling pegs