LIFTING

Safe and effective lifting techniques for finds depend on the type, size, shape and condition of the find and the nature of the burial environment. Here you will find general advice on planning for lifting and specific guidance on appropriate techniques and materials for different scenarios.

Planning for Lifting Finds

Some finds can be lifted using a trowel without any additional support and be placed directly into a finds container. Others may need extra support and specialist lifting techniques, for example those that are:

Too fragile to support their own weight.
Fragmentary.
Waterlogged.
Large and heavy.
Associated together in a context where relative positions are important.

Planning for lifting should include an assessment of the condition of the find and determination of the most appropriate lifting method. This may require the input of experienced personnel or a conservator.

Considerations when planning to lift a find are given in Table 5.1.

Table 5.1 Considerations when planning to lift a find

Lifting Techniques for Fragile Finds

Lifting techniques for fragile finds aim to support the find on a pedestal of soil or burial matrix to prevent damage during the lift and to prepare the find/pedestal for transport to a conservator by enclosing both within bandaging or a block. The most common methods available for lifting of fragile finds are:

Capping
Encapsulating
Block lifting

The appropriate method for lifting each fragile find must be determined on a case-by-case basis. Whichever method is chosen, a barrier material must be used between the surface of the find and the lifting materials. This prevents contamination of the find by the encapsulating or block lifting materials and facilitates separation of these materials from the find during micro-excavation.

Materials required for lifting fragile finds are given in Table 5.2:

Table 5.2 Common materials for lifting fragile finds by capping, encapsulation and block lifting techniques

Capping

This is the simplest of the lifting techniques for fragile finds and can usually be achieved quickly with few supplies (Table 5.2). It is ideal for lifting small, fragile finds such as low-fired ceramic loom weights and friable bone.

To lift a find by capping:

Isolate the find from the surrounding soil matrix by excavating so that the find is standing on a low pedestal of soil, 1 or 2cm high (Figure 5.1). Do not clean the surface of the find.
Place a marked find label beside the find on the soil pedestal for identification.
Record the location of the find within the feature on a plan or using GPS.
Infill any undercuts around the find using polyether foam. Do not use any type of paper or acid free tissue for this as they are likely to go mouldy.
Cover the upper surface of the find and soil pedestal with several layers of barrier material. Suitable barriers are damp polyether foam for wet finds and cling film or lighter-grade aluminium foil for dry finds.
Cut a piece of heavy-grade aluminium foil large enough to fit over and around the soil pedestal and mould it to fit closely (Figure 5.2).
Support the foil-covered find with one hand and undercut the soil pedestal using a sharp trowel, knife or palette knife. Be careful not to damage any underlying archaeology.
Wrap the undercut pedestal with several layers of crepe bandage for additional support, feeding the bandage underneath as the pedestal is undercut.
Lift the capped find and soil pedestal and place in finds tray or another suitable container with a find label. Additional support from a baking sheet or thin aluminium sheet may be helpful for the lift.
Pad around the lifted block with polyether foam to prevent movement and secure the package with masking tape.
Label and mark the outside of the packaging with all relevant details. Include: site, context, find numbers, date, and excavator initials. Mark the orientation of the find in relation to its original context. Outlining the area of the find within the package can be helpful for its excavation in the lab.

Figure 5.1 Capping method of lifting showing the registered find exposed on a pedestal of soil matrix

Figure 5.2 Capping method of lifting showing the find on a pedestal of soil matrix with undercuts supported with polyether foam and the find wrapped in aluminium foil or wet polyether foam

Encapsulation

This method is similar to capping but uses more robust materials. It can be used for larger, fragile finds (e.g., weapons, tools and spreads of objects) and for waterlogged organic finds (e.g., fragile textiles and basketry).

To lift a find by the encapsulation technique:

Isolate the find from the surrounding soil matrix by excavating so that the find is standing on a low pedestal of soil, 1 or 2cm high (Figure 5.1). A deeper pedestal may be required to support a larger find but be aware of underlying archaeology.
Place a marked find label beside the find on the soil pedestal for identification.
Record the location of the find within the feature on a plan or using GPS.
Infill any undercuts around the find using polyether foam. Do not use any type of paper or acid free tissue for this as they are likely to go mouldy.
Cover the upper surface of the find and soil pedestal with several layers of barrier material. Suitable barriers are damp polyether foam for waterlogged finds and cling film or light grade aluminium foil for dry finds.
Undercut the soil pedestal slightly using a sharp trowel, knife, palette knife or a slater’s ripper for larger pedestals. Be careful not to damage any underlying archaeology.
If the pedestal block requires further support, wrap with several layers of crepe bandage.
Cover the pedestal block with several layers of a release material, either cling film or light grade aluminium foil.
Apply the chosen encapsulation medium over the release material (see Table 5.2).
- Surgical gauze bandage with plaster of Paris: Apply strips of gauze bandage which have been dipped in a thin slurry of plaster of Paris. Overlap the strips of bandage and smooth after application. Apply two layers of bandage and include supporting splints to offer additional support to larger finds (Figure 5.3). Be aware that plaster of Paris only reaches full strength once dry and will not dry in wet conditions.
- Plaster-impregnated bandage (e.g., Modroc): This can be more convenient than gauze dipped in plaster. Cut the bandage to appropriate lengths before dipping in water and applying.
- Casting tape (e.g., 3M Scotchcast): This is a woven fibreglass bandage impregnated with polyurethane which sets rigid within 20-30 minutes after dipping in water. It is more expensive than plaster bandages but its increased strength means fewer layers are required and its reaction curing is effective in damp and wet conditions.
Complete the undercutting of the pedestal whilst sliding the chamfered wood board underneath for additional support (Figure 5.4). Wrap the board in waterproof material (polyethylene sheeting) in advance to prevent it from becoming wet and losing strength. Metal sheets may be used unless the block will undergo X-radiography. If extra support is required temporarily whilst undercutting, use blocks of polyethylene foam.
Lift the pedestal block on its board. Several people may be required for this, depending on its size and weight.
Ensure that encapsulation medium is dry or cured and secure the block to the board with bandages, string or straps.

Figure 5.3 Encapsulation method of lifting showing the gauze and plaster of Paris technique

Encapsulation method of lifting with undercutting

Figure 5.4 Encapsulation method of lifting showing the gauze and plaster of Paris technique with undercutting progressing to allow insertion of the support board underneath

Block lifting

The block lifting technique is particularly useful for large and heavy finds (e.g., earth-bound pottery kilns, oven and furnaces), registered finds requiring additional support and complete enclosure (e.g., whole ceramic vessels), assemblages of finds (e.g., grave goods from the same burial), large waterlogged timbers, mosaics and wall paintings.

To lift a find by the block lifting technique:

Follow the procedure for encapsulation but do not complete the undercutting.
Dig a trench around the encapsulated find broad enough to allow access to complete the lift.
Construct a plywood box of correct dimensions to contain the soil pedestal and find. Leave space between the soil pedestal and the sides of the box to accommodate support material, such as polyurethane foam. Select the most appropriate thickness of plywood for the weight of the block and reinforce the corners with brackets or angle strips.
Cut boards for the top and bottom of the box which are large enough to overlap its sides. Do not attach them at this time.
Position the box frame over the pedestal block so that it sits on the bottom of the trench and secure in position by packing with loose soil to fill any gaps where the frame meets the trench.
Cut a separator (e.g. Correx or foil covered card) suitable to divide the interior of the box into at least two sections. This will prevent adhesion of the two halves of the bulking material.
Fill the space around the find with the chosen medium (Table 5.2), for example expanding polyurethane foam or plaster with vermiculite or perlite filler. Apply in layers, allowing expansion to occur fully before adding more if using polyurethane foam and for plaster to dry. Leave the dividers in place (Figure 5.5).
If polyurethane foam is used, cut the foam level with the top of the box using a knife or saw blade.
Apply the pre-prepared lid and screw down or secure with straps. Reinforce the corners with angle brackets if necessary.
Undercut the soil pedestal using a sharp trowel, knife, palette knife or a slater’s ripper for larger blocks. Be careful not to damage any underlying archaeology.
For larger lifts, create a series of tunnels underneath the block and insert wooden battens or rods as the undercutting progresses, securing to avoid slippage. These act as lifting points to raise the block.
For smaller lifts, ease a support board under the block as undercutting progresses, followed by a pair of wooden battens beneath the board. Secure these to the box and use to raise the block.
Fix the lifted block and box to its permanent base, leaving the board in place.
Secure the box onto a wooden or plastic pallet, label the box on all sides and lid with site and find numbers. Include the site context orientation (N-S) and packing instructions with the box.
Transfer the block lifted find to a conservator as soon as possible. Rapid decay may occur in the uncontrolled environment within the box.

Figure 5.5 Block lifting method of lifting showing the box, divider and fill medium

Lifting a Vessel

A complete ceramic, glass, stone or metal vessel may require extra support during lifting which can be achieved using a bandage technique or a block lifting method. This is most likely where:

The contents of the vessel are in place (e.g., a cremation).
The ceramic body is low-fired and friable.
The metal is significantly corroded.
The vessel has been fractured by pressure from the overlying soil.

Block lifting is likely to be required for larger, heavier vessels containing soil which are more than 20cm high and require more support. Soil should not be removed from within vessels before lifting.

Materials required for lifting a whole ceramic are given in Table 5.3.

Table 5.3 Common materials required for lifting whole vessels by bandage or block lifting techniques

Bandage method for lifting a vessel

The bandage method offers sufficient support for a ceramic or glass which retains its integrity. It can be achieved using only crepe bandage or may also employ plaster bandage or casting tape for additional support. Before lifting, prepare a suitable container to receive the find, for example a box lined with polyether foam padding.

To lift a complete vessel by the bandage method:

Excavate approximately a quarter of the upper side of the vessel, leaving a thin layer of soil on its exterior surface and ensuring that any undercuts or handles remain covered and protected by soil matrix. Use only wooden or plastic tools which will not damage the friable ceramic fabric.
Do not disturb the soil within the vessel, this provides support and can be micro-excavated in the laboratory.
Begin winding crepe bandage around the rim and top of the vessel, overlapping the edges and tucking the end of the bandage into one of the upper folds.
Fasten the bandage with a safety pin ensuring that there is tension in the bandage (Figure 5.6).
Excavate the remainder of the vessel exterior in spits, winding the bandage around the vessel as it is exposed.
Make an extra turn of the bandage at the base of the vessel and begin winding the bandage back up in the opposite direction.
Fasten the bandage at the top of the vessel, again ensuring that it is under tension.
If the vessel requires additional support:
- Wrap several layers of aluminium foil or cling film around the bandaged vessel to act as a barrier or release layer.
- Dip plaster bandage or casting tape in water to activate and wrap around the vessel.
Free the base of the vessel from the soil matrix and lift the vessel using two hands. Expect it to be heavy.
Place the vessel upright in the prepared container and pad with polyether or polyethylene foam to prevent movement.
Include find labels in the container and label the outside of the container (include context orientation and arrows to show the top and bottom of the vessel).
Transfer the vessel to a conservator as soon as possible.

Figure 5.6 Bandage method of lifting a vessel

Block lifting a vessel

Block lifting can be an appropriate method for very fragile ceramic or glass vessels. As with the bandage method, prepare an appropriate container to receive the block containing the vessel, such as a strong box.

To lift a vessel by the block lifting method:

Excavate around one half of the vessel (Figure 5.7), leaving a thin layer of soil on its exterior surface and ensuring that any undercuts or handles remain covered and protected by soil matrix. Use only wooden or plastic tools which will not damage the friable ceramic fabric.
Do not disturb the soil within the vessel, this provides support and likely contains archaeological evidence. It can be micro-excavated in the laboratory.
Line the excavated hole with aluminium foil or cling film to act as a barrier and release layer, ensuring that it covers the exposed surface of the ceramic vessel.
Fill the excavated hole around the ceramic with expanding polyurethane foam or plaster/vermiculite mix and allow to dry.
Repeat this process for the remainder of the vessel, creating a block which surrounds and contains the vessel.
Excavate around the block to allow it to be wrapped in crepe bandage or gaffer tape to hold the block sections together.
Lift the block and place upright in the prepared container and pad with polyether or polyethylene foam to prevent movement.
Include find labels in the container and label the outside of the container (include context orientation and arrows to show the top and bottom of the vessel).
Transfer the vessel to a conservator as soon as possible. Be aware that polyurethane foam degrades over time.

Figure 5.7 Block lifting method of lifting a complete vessel

Further Information

Barham, E. 2007. Controlled lifting and x-radiography of gold threads from ancient archaeological textiles. In S. O’Connor and M. Brooks (Editors). X-radiography of Textiles, Dress and Related Objects. Routledge, London, UK.

Cronyn, J. 1990. The Elements of Archaeological Conservation. Routledge, London, UK.

Guichen, G. de and Nardi, R. 2008. Mosaics Conservation– Fifty Years of Modern Practice. Getty Conservation Institute, Los Angeles, CA.

Hadley, P. et al., 2010. To block lift or not to block lift? An experiment at the Early Mesolithic site of Star Carr, North East Yorkshire. Internet Archaeology

Payton, R. 1992. Retrieval of objects from archaeological sites. Archetype Books, London, UK

Price, J. 1975. Some field experiments in the removal of larger fragile archaeological remains. Studies in Conservation, 20:153-164.

Price, J. 1986. The removal and conservation problems of a twelfth-century stone screen, with notes on Purbeck marble. Studies in Conservation, 31:142-147.

Robinson, W. 1998. First Aid for Underwater Finds. Archetype Publications, London, UK.

Rowley-Conwy, E. 2020. Treatment of a block-lifted chicken skeleton. In C. Caple and V. Garlick (Editors) Studies in Archaeological Conservation. Routledge, London, UK.