Lord’s Cricket Ground
Client
Lord’s Cricket Ground
Client Brief
To rectify water ingress coming through the front walkway of the balcony, with water dripping through onto the lower balconies.
Site Inspection
BCL attended the site in December 2008 to inspect the leaking gutter joints to the 2nd and 3rd floor levels of the pavilion balconies. In discussion with the client, we established that there was an additional work requirement relating to the replacement of a thin coat screed and associated expansion joints of the front walkway. The requirements for the screed and expansion joints interfaced very closely with the gutter repair which, after careful consideration we explained that we could offer a solution for the whole project.
We prepared a proposal for both the 2nd and 3rd floor balconies, which due to budget constraints, resulted in only the 3rd floor balcony works being undertaken. The deadline was completion before the 1st Test match of England v West Indies on 6th May.
A former proposal was prepared dealing with the anticipated work, which was duly reviewed and then accepted.
Product Selection
The gutter joints were to be reformed using Belzona 3131 (WG Membrane), incorporating bridging tape, with Belzona 4131 (Magma Screed - Light grey) laid along the full length of the balcony front walkway. A full length joint between the concrete cantilevered structure and the gutter was to be formed using Belzona 4521 (Flex Fluid).
Project Details
Work commenced on 20th March to remove the screed and it quickly became apparent that there were other construction issues which needed to be assessed and resolved.
1. The removal of the existing thin coat screed (6mm thick), revealed a further screed had been laid onto the concrete structure which, along its 90.0m length, varied in thickness from 10mm up to 40mm in places. We established that, as a result of an incorrect original alignment on the cantilevered concrete sections, the additional screed had been laid to rectify the problem. This screed was very loose and had to be removed and replaced with Belzona 4131 (Magma Screed), but with the screed bulked up to 50% by volume with an aggregate to provide a more cost-effective solution. This screed also needed to be laid to create new falls on the balcony walkway gutter, with the originally allowed 6mm thickness of Belzona 4131 (Magma Screed) being laid to complete the surface walkway.
2. We also exposed ‘infilled’ expansion joints between the individual cantilevered sections; these had been filled with a machine grout. However, the client’s architects insisted that the grout was not removed. We therefore decided to reflect the locations of each joint (26 in total) up through our new screed to prevent the defect occurring within the Belzona screed, and forming new expansion joints using Belzona 4521 (Flex Fluid).
3. Finally, the additional screed also masked a number of problems around the front handrail position and its interface to the concrete and to the gutter.
Solutions were put forward to remedy the situation using both Belzona 1821 and Belzona 4521 and these were agreed by all parties.
The first layer of screed to be laid to falls, was bulked out using a 5 – 8mm nominal sized kiln dried bauxite aggregate, which was pre-coated with Belzona 4921 (GP Conditioner), before the Belzona 4131 was combined into the mix.
Support for the galvanised guttering section proved very difficult as the pre-formed gutter had been cut and weakened around each handrail support post (with over 40 connections having to be reformed.)
On completion we carried out onsite testing of the Belzona 4131 (Magma Screed) for surface slip test and in both wet and dry conditions, and can report that in both conditions the Belzona 4131 achieves a Low-Risk rating.
The work was completed on 1st May, in time for the test – which England won!!!
As a result of the work, the 2nd floor balcony is scheduled to be undertaken during the next winter period.
« Back to Case Studies