Survey Access

Jonathan Taylor

Church buildings are notoriously difficult to survey. They are predominantly single storey structures with high walls, often with towers or spires. Much of the structure is beyond the reach of ordinary ladders, and many surfaces cannot be seen from the ground, including gutters and the upper surfaces of mouldings, beams and wall plates for example. Close inspection of these features is often necessary to assess the condition of the structure and for producing survey drawings and records for planning repairs or alterations. Survey work, structural investigations and recording usually have to be carried out months before repair work is carried out due to the time required to prepare estimates, program work, raise the necessary finance and gain the approvals required. The erection of a full scaffold so far in advance of the work is an expensive option as either it will have to be taken down and re-erected for a second time, or it will have to remain in position for months unused. Each time a building is scaffolded its fabric is exposed to greater risk of accidental damage, so scaffolding needs to be carried out the fewest number of times possible.

MEWPS come in all shapes and sizes: mounted on a dumper truck (above), small cherry-pickers become extremely manoeuvrable in tight spaces

Today there is a growing variety of possible temporary access solutions which provide safe alternatives to a scaffold. Each has its merits and disadvantages. For some work, direct access is essential. Samples may have to be taken, for example, to assess the amount of stone replacement that is likely to be required, or for archaeological investigations. This work must be carried out from a safe and stable vantage point. Direct access also allows essential maintenance work to be taken at the same time, such as for cleaning out gutters.

It is often possible to make a survey inspection remotely, either from the ground or from a higher level, or even from the air, using a camera or video to inspect and record the more obvious defects, or a stereo camera for the production of photogrammetric survey data. Laser scanning survey equipment, however, needs an extremely stable base and the temporary or mobile platforms described here are generally unlikely to provide the stability required.


Temporary access from a stable platform is usually achieved using either a scaffold tower or an elevating platform. As these provide direct access to the face of the building they can be used for surveying or for carrying out physical investigation. When selecting the most suitable system, key points to bear in mind are:


Interior restrictions
  • Access - restrictions on equipment size and weight imposed by maximum door widths, the need to transport equipment across steps, and the ability to turn in often confined spaces
  • Floor loads - historic pavements, tiles and other floor finishes may be damaged by heavy loads; structural damage may be caused where there are vaults and other structures below
  • Space - inside the church, pews, tombs and other features may restrict the available space for erecting scaffolds and platform lifts
  • Safety - will the platform remain stable on the floor surfaces and below ground conditions?

Larger vehicles provide the longest reach, in this case 40 metres. (© EPL Access Ltd)

Exterior restrictions


  • Access - restrictions on equipment size and weight imposed by access to the building through churchyards, including gate widths, the need to transport equipment across soft ground, steps or steep slopes, and the ability to turn in often confined areas
  • Ground loads - historic paving, turf and other exterior surface finishes may be damaged by heavy loads; structural damage may be caused where there are vaults and other structures below
  • Space - inside the churchyard, trees, surface finishes, headstones, tombs and other monuments may restrict the available space for erecting scaffolds and platform lifts: in the street, pedestrian and vehicular traffic requirements may similarly restrict the choice of system; the location of below ground structures such as tombs and vaults may also impose limitations
  • Safety - the stability of the platform may be adversely affected by ground surfaces (hard or soft landscaping), below ground conditions and wind

Small scaffold towers present a low-tech option. Because they can be brought into the church, churchyard or street in individual components they can be assembled almost anywhere. Their chief restrictions relate to their size. The larger they are, the longer they take to assemble and the less manoeuvrable they become. Where access conditions are suitable, the most effective means of providing a temporary but stable platform for direct access at a high level is a mobile elevating work platform (MEWP). There are many different sorts including small, trailer-mounted 'spider' systems which are designed to be wheeled by hand through ordinary doorways; and larger vehicle-mounted elevating platforms known as 'cherry pickers'.

Small trailer-mounted systems are much quicker to assemble than a scaffold. Commonly called 'spiders' because of the appearance of the stabilising legs which extend out from the trailer when the platform is raised, these systems generally provide access up to 17 metres. Trailers are designed to be sufficiently narrow to fit through the doorways of most churches, but they are long, making them difficult to manoeuvre in tight spaces, and they are far too heavy to negotiate flights of steps. It may also be necessary to provide floor protection, particularly where there are vulnerable surface finishes such as tiles.

Outside, a much greater height can be achieved using cherry pickers which can usually reach a height of 40 metres. The largest available at present reaches up to 72 metres in height. Cherry pickers can also reach out laterally, for example across inaccessible ground such as a churchyard, provided that the platform remains within a safe working envelope. On soft ground the load may be distributed across tracks, although this adds both time and expense.


Mounting a camera or other survey equipment on a pole extends the reach of a camera from safe vantage points to investigate more remote areas. One company, Hi-cam Ltd, offers this service using a digital camera fixed to a 55-foot mast mounted on a van. This has the same site access limitations as a MEWP. Its advantages are that the professional consultant (architect, surveyor or an engineer) can examine the structure from a monitor inside the van, without taking his or her feet off the ground, and that it is a dedicated photographic system. No other equipment needs to be hired.


Skycell's airship provides a ready access to interiors as well as exteriors enabling close-up photographic surveys and the inspection of defects via a radio link to a monitor on the ground. The detailed inset photographs show the quality of its photographic record. (©Skycell Limited)

One of the most exciting recent developments has been the introduction of a light airship by Skycell Limited, a company based in York Science Park. This helium-filled balloon is radio-controlled and powered by three electric motors. A lightweight medium format digital camera suspended beneath the airship is linked via a wireless connection to a monitor on the ground. The airship has none of the access limitations of a truck or van, so it can fly inside larger buildings which cannot be accessed by a MEWP, such as a church nave with a small or awkward entrance, or a flight of steps, and it can survey the exterior of buildings where churchyard monuments, soft ground and other such obstacles would prevent vehicular access. Its interior height range is unlimited and its external height range is more than adequate to survey any ecclesiastical building (although permission is required from the CAA for operations over 200 feet). The principal limitation of this system - and its advantage - is that, like the polemounted camera, the airship is dedicated to photographing and filming the structure and fabric of a building. It does not provide direct access.


Rope access specialists provide remote inspection and recording services, as well as repairs. WallWalkers (shown here), for example, employ staff who have been trained in the use of lime mortars. (©WallWalkers)

Steeplejacks and rope access specialists are able to carry out surveys, non-destructive testing and structural repairs at a high level without scaffolding. Steeplejacks tend to work from ladders and supports fixed at a high level, as well as from ropes, while rope access specialists tend to work exclusively by abseiling with two ropes attached to a safety harness, although the distinctions between the two trades are becoming less clear.

As a craft, rope access is relatively new, having really developed over the past 20 years or so. Although pioneered by rock-climbers who took to the building industry, today it is increasingly common to find specialists from within the building industry who have trained in rope access, including building contractors and craftsmen, structural engineers and other professionals. Training and practice is regulated by the Industrial Rope Access Trade Association (IRATA), and there is a British Standard code of practice, BS7985. The craft has an excellent safety record. Full qualification is attained in three stages, each involving five days training and examination separated by periods in which experience is gained at work under the supervision of somebody more experienced.

Rope access has the advantage that it is not limited to the one side of the building which can be reached by a MEWP. Most of the external fabric of even the largest church will be accessible by rope, and many interiors will also be. Rope access can be used to provide direct access if the person on the rope is qualified to carry out the investigation or repair work required, or if the specialist craftsman or professional required is prepared to undertake the necessary rope access training. It can also be used for recording and investigating using a digital camera or video, linked (usually by cable) to a computer on the ground. A professional can watch the monitor and direct the investigation without needing to leave the ground.


EPL Access, Tel 08702 407080

Hi-cam Ltd, Tel 01244 679199,

IRATA, Tel 01252 739150,

National Federation of Master Steeplejacks and Lighting Conductor Engineers

Skycell Limited, Tel 01904 435100

WallWalkers, Tel 01531 670966

This article is reproduced from Historic Churches, 2002


This article was prepared by JONATHAN TAYLOR and EDWARD GREEN

Further information


Measured Building Surveys

Non-Destructive Investigations

The Appointment of Professionals for Quinquennial Inspections

Quinquennial Reports


Survey/Maintenance access

Ecclesiastical work
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