Basic land surveying equipment

4. Moisture meter

The basic machine uses two metal probes and measures the electrical resistance across the probe pins. The wetter a material they are pushed into, the less resistance there is across the material due to the presence of moisture and the higher the reading given. A moisture meter is used to check the moisture content of timber and walls above and below the damp proof course to check that the damp course is working effectively. Several readings should be taken to ensure that an accurate average is obtained. You should also make a visual check to ensure that a damp course is present within a building and take into account the age and construction of the building.

5. Camera

The improvements to cameras in the last ten years have been phenomenal. Digital imaging has made the old film-based systems nearly obsolete. Time and date recorded photographs of properties and different aspects of the survey can

be instantly captured, and used as a historical record, especially for dilapidation surveys. This technology enables images to be stored and emailed very easily, enabling a report to be completed more quickly. A digital camera is very useful when conducting measured surveys as it enables you to take a second look at any aspect that you have missed, for example, you can count brick courses from a photograph.

6. Binoculars

These extend your range of vision, especially in surveying roof work. Small defects can be spotted more easily by using binoculars to identify weaknesses within the structure. Binoculars are especially useful for high-rise buildings where your scope of view of the outer walls is limited from the inside. A set of 10x8 binoculars is all that would be required for a surveyor’s tool kit and will help to reduce eye strain when surveying exteriors in strong sunlight.

7. Boroscope

This is a very useful tool for gaining access into a structure with the minimum of disruption and damage to the fabric of the building. The boroscope consists of a telescope with a mirror at the end that diverts the line of sight by 90 degrees. This is especially useful when you need to inspect the cavity of a wall. A light within the equipment enables a good visual inspection of these inaccessible areas of a structure. Adding a camera to this process enables a record of the inspection to be made.

To use the equipment, a hole must be drilled through the outer part of the structure that you are trying to inspect. This must be oversized to allow the camera to slide though easily. Once the inspection has been carried out, the boroscope is withdrawn and the hole must be made good. Obviously, the larger the inspection area, the more holes you will have to drill in order to make an evidenced judgement as to the defect.

8. Thermal imaging equipment

This is very complex equipment that requires specialist training to use. It is often better in smaller building surveying practices to obtain the services of a specialist subcontractor to undertake this work. A thermal camera with some form of recording media will be required along with a digital player to observe the buildings.

9. Spirit level

This is available in a number of differing lengths and measures the horizontal and vertical positions of the surface it is placed upon. Care should be taken when measuring vertical walls as you obtain a better measurement when using a longer level.

10. Optical levels

An optical or automatic level, as we can see from the photograph, is used with a staff to establish what the difference in level is across two or more points.

This can be used to establish the settlement of a building, whether it is even or is dipping in one corner. Taking several levels over a period of time would provide a course of monitoring to establish if the building is continuing to settle. A known reference point away from the building must be established as a control point to establish if the building levels are moving.

Theodolites, ranging poles and optical reflectors can be used to survey large areas of land and buildings to quickly plot an area to scale. Modern surveying equipment uses global positioning equipment to measure electronically an area by using satellite navigation to triangulate a known point. All you have to do is locate a grid coordinate and then print out your survey.

Exercise 2. Decide if the following statements are true (T) or false (F):