Measured Building Surveys

Our information is used by many, but primarily Architects, Engineers and Surveyors. We cover all property, from residential and commercial buildings, to educational and heritage buildings, even including land. One of our previous and most challenging instructions was a Grade ll* windmills in Sussex!

Blackacres’ drawings are highly accurate and based off laser scan for its root data, because of this, we typically achieve a room accuracy of 1-3mm which is a vast improvement on previous surveying methods. Depending on the clients requirements we can provide a high or low level of detail (LOD). All structural elements, height information, plant and pipework can all be included.

As RICS surveyors we comply with the the relevant RICS Professional Guidance, Measured surveys of land, buildings and utilities, notwithstanding this guidance, in reality we find our information is significantly more accurate. Our team of scanning experts and CAD technicians are experienced in providing this information and consequently we experience a high repeat client list.

     1. Point Cloud dataset

     2. Set of 2D drawings (Floorplans, Elevations, Sections) 

     3. Photographic records

     4. 3D model

     5. Scan to BIM

Blackacre also provide Topographical Surveys. During our time on site, we can combine our digital laser scan, with our GNSS receiver information. Following this, we are able to provide external land surveys with fixed control points, georeferenced to OS and height information above mean sea level (AMSL).

How does it work?

The reason Blackacre achieves such accuracy is due to the technologies of today. We use Time-of-Flight (TOF) laser systems and complex software to transfer reality onto paper with tolerances less than a few millimeters.

The scanning phase: We use a Terrestrial Laser Scanner (TLS) which emits a laser beam up to 80m away. After hitting a surface, the laser bounces back, it’s then picked up by the receiver on the TLS unit. As the speed of light is already known (299,792,458 meters per second), the distance of the surface can be calculated, by the period of time from emitting to receiving the laser beam. We know this as the Time-of-Flight (TOS) method of scanning.

The TLS unit rotates and emits laser beams at a rate up to 500,000 times per second. It rotates and scans for a few minutes, then we reposition it to gain data from another angle. These stations are ‘registered’ together, culminating millions of different points, forming a geomatic ‘Point Cloud’. This essentially means a 3D digital representation of a building.

The drawing phase: The point cloud is rotated, manipulated and sliced to view any part required. This produces our Measured Building Survey 2D drawings. It’s possible to transfer the information into a line based drawings with useful CAD software such as AutoCAD or Revit.

Further to providing the client with the ‘point cloud’ in a number of different formats (.tdx, .tzf, .e57, .ptx, .las, .pod, .rcp) we deliver 2D drawings and a 3D model of the building. If desired, the client uses this for BIM (Building Information Modeling).