Setting Out for Construction
We use accurate setting out plans for setting out for construction across the north of England.
A key element of the construction process is absolute accuracy when setting out buildings or infrastructure around Great Britain. Our experienced and dedicated land surveyors ensure that all setting out is implemented with accuracy and efficiency using a combination of Leica robotic total stations and GPS equipment.
If the correct process flow is followed and the appropriate quality checks are put in place when the work is being done then any potential errors will be picked up immediately. Taking the time to ensure we have the most up to date version of a site plan and that the building coordinates are calculated correctly and uploaded onto our Leica Total Stations rather than calculated by hand is also imperative. We realise that eliminating the amount of human error on a project is key to reducing waiting times and minimising costly mistakes.
The following is our proven process flow of how we deliver any setting out project we undertake:
- All total stations are calibrated on a yearly basis by a trained professional. A certificate of calibration is available for each piece of surveying equipment and can be sent to the client prior to going on site. Tribrachs and Levels are also subject to rigorous tests on a regular basis to ensure that they are working correctly.
- Architects and engineers drawings are also checked and overlaid on top of each other as well as on top of the topographic survey to ensure that any discrepancies are easily detected prior to a site visit.
- Setting out coordinates are calculated prior to going on site using Applications in CAD software and uploaded onto our Leica total stations. There are no human calculations used in this process which greatly reduces the risk of human error.
- Using the total station with the uploaded coordinates, our land surveyors can easily set up a network of control stations and reference objects in order to set out the points required on site.
- Positional Error Checks– once work has been completed on site our surveyors will check that the position of the building is in line with the design and layout of the plans from the architect or client. Measurements taken include:
- Building position from the boundary
- Position of the building from other buildings or from potential new roads, drainage and pavements.
- Orientation of the building in relation to the site (is it the facing the right direction?)
Details of the measurement checks are written on the site plans and left with the client and a copy kept in our archived folders for each site.
- Individual Peg Checks – the coordinated points of the building are then checked by tape measure at random intervals to ensure that the size and shape of the building is correct. These measurements are then written onto the site plan and either left on site or stored along with all of the site details at our offices to ensure a historical record is retained for future reference. The peg to peg checks will highlight any discrepancies in the coordinated points versus the original architect’s plans and any discrepancies that may prompt a review of any of our equipment’s accuracy levels.
- Whilst on site, we are often asked to set out further building plots, pavements or boundaries not requested in the original scope of the project. In this instance our surveyors will speak to the guys in our office who will relay coordinates over the telephone. The risk of human error is greatly increased in this the instance and all points calculated are checked by tape measure and against the original setting out plan. A note is made of the calculations taken and checked again when our surveyors return to the office.
Examples of some of our setting out projects include:
- Individual building plots for residential clients leading to more complex multiple plots for house builders.
- Large scale apartment blocks and office buildings.
- Roads and highway infrastructure.
- Sewer lines.
- Drainage schemes.
- Complex steel infrastructures.
Frequently Asked Questions
(1) How can I position my building on site from proposed drawings?
The proposed site layout should be based on the same grid as the original topographical survey. From the layout we can extract s/o coordinates for the building corners and using an electronic theodolite referenced to existing site control we can peg out the required corners.
(2) What if there is no existing survey and just a dimensional layout?
The building can still be set out but its overall position within the site cannot be positioned as accurately as it would be from existing site control. A base line would have to be set up by measuring directly off existing features shown on the site plan and then the building can be set out accurately from this base line.
(3) Can building corners be set out using GPS?
Yes and no - Setting out using GPS is a great way of pegging out a boundary line over large open areas of ground. It can also be used to set out building corners for site clearance and footings. Its relative accuracy of 20-30mm is not good enough to set out building corners for brick work or steel work. Electronic theodolite is still the best way to achieve relative accuracy in setting out.