Ashmolean Museum, Oxford University

Ashmolean Museum, Oxford University

Solution: Waterproofing
Architect: Renlon
Contractor: Rick Mather

Built in the 1670’s and the world’s first university museum, the Ashmolean Museum, part of Oxford University, recently underwent redevelopment to make it suitable for modern visitors. Sika 1, from renowned manufacturer of building materials Sika, was chosen to provide superior waterproofing to basement areas and protect the priceless artefacts they contain.

The £61 million project saw all but the original, Grade 1 listed elements of the structure demolished and replaced with a stylishly designed and fit for purpose new building. The redevelopment has doubled the gallery space of the museum and created dedicated conservation and education facilities. Crucially, given the Ashmolean’s collection of rare objects, it provides excellent environmental control.
Famed architect Rick Mather designed the structure, including its4000m2 basement. To provide the exacting standards of environmental control that the curators and managers of the museum required, consulting structural engineers Dewhurst Macfarlane and Partners specified Sika,safe in the knowledge its waterproofing system certified full protection.

The basement’s vast size meant the system required a total of 250 tonnes of Sika’s pre-bagged mortar, combined with 27,500 litres of Sika1. The provision of materials had to fit in with tight site deadlines, to which Sikademonstrated its ability to supply large specifications under pressure.
The system was installed by specialist contractor, Renlon. Over the reinforced concrete structure, the company cast a layer of Sika1 Spritz Mortar. This was followed by a second and third layer of Sika1 Render and Finishing Mortar to the walls and, equally, a second and third layer of Sika1 Screed Mortar to the floor – creating a three layer system of protection.

Using Sika’s innovative pre-bagged mortar solution, the company was assured of creating the perfect mortar mix.

To ensure no moisture permeated the structure, Renlon applied Sika’s EpoCem, an epoxy cementitous combination material, which acts as a surface mounted DPM when used in combination with Sikadur 32. This was essential to maintain the integrity of the artefacts held within the basement. The product also heavily reduced time on the project. Once applied on top of the mortar, it sped up drying times, allowing work to proceed ahead of schedule.

The waterproofing was specified to BS8102 Grade 4 – the highest recognised standard of waterproofing protection. This required a high level of technical ability to apply the Sika system. To ensure these requirements were met, Sikaprovided Renlon with comprehensive technical and practical training for several of its staff members.

BS8102 Grade 4 is chosen for the most sensitive environments. It denotes a basement area that is totally dry and 100% vapour impermeable. The only choice for the basement at the Ashmolean museum, given that it is home to a collection that includes such curiosities as Oliver Cromwell’s death mask and the lantern that Guy Fawkes carried on the night of the gunpowder plot, it is a key element of the environmental control that was specified in the design of the building.

The main contractor and client stipulated that as many sustainable products should be used on the project as was possible. Sika packaging complied with this policy, as it is all sustainably sourced.

Certified by the British Board of Agrément, the system guarantees the museum and its precious historical objects, stored within the new basement, total security for years to come.


ika1 provides a structural waterproofing render that is proven to resist water pressure below ground for over 90 years. Combining Sika1 with renders, screeds and mortars, it effectively blocks all capillaries, preventing the intrusion of water.

Now open to the public after the lengthy redevelopment, the Ashmolean Museum is striving to set a new mark for cultural institutions and attractions. With the help of exhibition planners Metaphor, whose clients include the Guggenheim Museum, Bilbao, and the Victoria & Albert Museum, London, they are using the added basement space to showcase their remarkable collection – protected from environmental damage by the ever popular Sika 1.bridge, Proun required a waterproofing solution that was unobtrusive. Due to the nature of the structure and the high profile nature of the project, it also had to be versatile, proven and 100% reliable.

Sika 1, from leading specialist construction materials provider Sika, was the answer, providing the venue with a proven waterproofing solution to keep the damp away from its high profile visitors and luxurious décor whilst enabling the structure to be easily inspected.

Providing protection from water and vapour ingress, Sika 1 is a complete pre-bagged waterproofing system that incorporates a specially developed admixture and all mortars and screeds.

Featuring a colloidal liquid, the Sika 1 admixture is mixed into the system. It then reacts to water by turning into a jelly-like substance, blocking all gaps and capillaries, and providing an impregnable and invisible seal.

Bonding monolithically with the substrate, it provided the ideal product for the project. Once applied to the brickwork walls, it essentially becomes one with the structure. If any faults or cracks appear in the substrate, they will also show up in the waterproofing system allowing inspectors to accurately maintain the bridge.

Peter Swain of Proun Architects commented, "Being physically beneath the bridge there were many challenges, especially in solving waterproofing details to accommodate structural movement."

Tom Bugg of Quickseal Specialist Contractors stated;”Being involved with Sika and Proun Architects from design stage to completion ensured that a relatively complex structure was successfully waterproofed in line with the main Contractors programme and cost budgets.”

To complete the waterproofing solution, Sika's advanced jointing system, SikaDur Combiflex, was also specified. A high performance joint sealing system, it provides proven protection from water ingress to all gaps between cracks, joints, panels and walls.

Certified by the British Board of Agrément (BBA), Sika 1 meets the requirements of BS 8102 Grades two, three and four, with grade 4 being the highest recognised standard of waterproofing protection.

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