Leaking concrete gutter? Douglas Snell explores the problems with "Finlock" concrete guttering:
Most of us are familiar with the plastic or older iron guttering that edges our roofs to catch the rain and safely divert it into a drain or soak-away. But unless you have owned a house built between the 1950’s and 1970’s, you may not have come across “Finlock” guttering.
Finlock guttering is made from preformed concrete sections that act as a wall plate for the roof rafters, a lintel (above a window or door) and the gutter, all in one. These photographs are from a recent Building Survey in Watford by Woodward Chartered Surveyors Douglas Snell.
Concrete was used because of a shortage of metal in the post war period and to designers of the day this multipurpose use looked like a great design solution.
After a while the original bitumen lining in these gutters starts to fail and water can track back into the property causing internal dampness. Everyone has their own “fix” for a failing Finlock gutter, but the solution attempted by this home owner was to stick some plastic guttering inside it, which was never going to be effective.
Some recommend grinding off the gutter flush with the wall, fit a plastic soffit over the nasty mess left behind and attaching new plastic guttering. Others offer re-lining of the concrete gutter in bitumen and foil or EPDM (a rubberised roof lining material).
It all depends on the reason for the gutter failure, whether the concrete sections have moved (perhaps when replacing windows) or the lining has simply deteriorated.
If you have a guttering or internal damp problem and would like the advice of a Chartered Surveyor, please contact Woodward Chartered Surveyors.