Waterproofing and Damp Proofing Consultants
HIGH COURT JUDGEMENT
OUTWING CONSTRUCTION –V- THOMAS WEATHERALD
A recent ruling in the High Court of Justice, Queens Bench Division of the Technology and Construction Court, is likely to have significant implications for the waterproofing industry.
Thomas Weatherald Ltd. was the main contractor responsible for the design and construction of a new nursing home at Bramley Hill in Croydon. The structure included the construction of a basement built into the well-drained chalk on the site.
The floor was constructed in reinforced concrete. The walls were constructed out of two skins of concrete block, sandwiching a layer of concrete in between.
The structure was waterproofed externally using Bitite, a bonded sheet membrane.
A land drain was positioned approximately one third of the way up the wall, and discharged to a soakaway a little distance from the building.
The construction of the basement structure, waterproofing and land drain was subcontracted to Outwing Construction.
Shortly after completion, leaks occurred internally after a period of prolonged and heavy rainfall. Thomas Weatherald withheld money from Outwing Construction, on the basis that they had incurred additional expense in applying Sika render internally. Outwing sued Thomas Weatherald for the balance of money owing, and Thomas Weatherald counterclaimed for the cost of the Sika installation together with other damages.
THE OUTWING CLAIM
Phil Hewitt, Expert Witness for Outwing Construction, argued that there was a significant fault with the design, for the following reasons:
1. Clause 3.3 of BS
8102, Code of Practice for the Protection of Structures Against Water
from the Ground, states that the designer should i) Consider the consequence
of less than adequate workmanship, ii) Consider the consequence of leaks
and iii) Consider the form and feasibility of remedial work.
THE THOMAS WEATHERALD DEFENCE AND COUNTERCLAIM
John Mawditt, Expert Witness for Thomas Weatherald Ltd., argued as follows:
1. Clause 3.1.1 of
BS 8102 says that the membrane alone must be capable of withstanding a
head of water of at least 1m without leaking.
Recorder Colin Reese QC found for Outwing Construction without any qualification. In his 25 page judgement, the following exact extracts are pertinent:
1. Having read their
reports and heard their oral evidence, I unhesitatingly prefer Mr. Hewitt’s
evidence and reject Mr. Mawditt’s views that a self-adhesive tanking
system of waterproofing such as that which was installed could be expected
to resist water penetration in the event of a build up of hydrostatic
This is a High Court judgement, and now sets a precedent for future similar cases. As a result, designers of waterproofing systems should now give serious consideration to:
1. Ensuring that, where
there is any risk of water pressure building up against a membrane, (whether
it is permanent or temporary) the water is removed before it comes into
contact with the membrane.
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