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  Water ingress - information on water ingress into buildings
  Austin Winkley & Associates has particular skills in the assessment of water ingress into buildings.  This interest dates from the late 1970s when Austin Winkley wrote his conservation thesis on the topic of rainwater and how it is controlled in historic buildings.

A copy of this thesis can be downloaded here.  (The file is 15MB in size.)

The proper upkeep of rainwater goods (gutters, downpipes, gullies and suchlike) is a vital and often overlooked aspect of the care of existing buildings.  Many historic buildings have inherent problems in the design of their rainwater disposal systems, exacerbated in many cases because they are not easily accessible for clearing or repair on a regular basis.

We have extensive experience not only of diagnosing the causes of water ingress into buildings and the building fabric, but of proposing and carrying out creative and discrete alterations to ensure that the risks of water ingress are minimised.  Our project at St Giles' Church Camberwell is an example of this, where water ingress into the valley gutters had caused repeated outbreaks of dry rot in the roof timbers.  The valley gutters were virtually impossible for the parish to keep clear of leaves and blockage from the surrounding trees, due to the height of the building (it is cathedral-like in scale).

Our strategy was to reduce to a minimum the risk of blockages by applying eight simultaneous measures, such that if one or two of them failed, the others would continue to protect the building.  This approach may seem excessive, but only if one forgets the timescale over which these sorts of  buildings need to be cared for - a timescale which extends to multiples of 50 years.  (Many of the problems of historic buildings arise from an application of an investment mind-set more appropriate to shorter-lived buildings.)  These measures were:

  • the sumps to the lead parapet gutters were made very large indeed
  • the bottom of the sumps was lowered, and a very large through-the-wall outlet was created (between the corbels of the projecting parapet wall).  This outlet replaced a swan-neck arrangement.  Swan-neck arrangements will block regularly; a large through-the-wall arrangement will not except under exceptional circumstances
  • this outlet discharges directly into a very large rectangular hopper head
  • the hopper head has an overflow pipe so that if it gets blocked, this is apparent, and the water is thrown clear at the front of the hopper rather than soaking the wall behind
  • the 100mm (4") diameter downpipes were replaced with 150mm diameter (6") downpipes.  A 4" downpipe will block easily; a 6" downpipe blocks rarely.  (This solution will not be appropriate on all historic buildings - St Giles is large in scale and so the 6" pipes were aesthetically appropriate - in fact, more appropriate than the 4" ones.  It is the case however that the majority of rainwater pipes on existing buildings would now be considered too small to cope with some of the extremes of weather we now face.)
  • the hoppers and rainwater pipes were spaced off the face of the wall by means of bobbins
  • easy access for laypeople was provided to the high level parapet gutter.  This was via a door out from the tower bell ringing chamber and down some steps into the gutter
  • guard-rail edge protection was provided along the gutter, again so that laypeople can safely gain access for clearing, maintenance and inspection

Every element of the works had to be carefully designed in order to ensure that the aim of safeguarding the fabric of this important 1844 Grade II* listed building, which Pevsner credits as being  Scott's "first essay in the Gothic style".

This work was generously funded by English Heritage and the Heritage Lottery Fund.