Problems with concrete gutters
Concrete gutters or Finlock gutters were installed during the 1950's, 60's and 70's to carry out two functions of closing the cavity at the top of the brickwork and providing a wrongly assumed maintenance free gutter system. The gutters comprise units that vary in length between 200 and 600 mm and either the joints have been sealed with bitumen or a similar substance or the gutters are lined, often with torch on mineral felt.
When the seals deteriate they leak quite badly and because they cross the cavity, a good proportion of the water can actually leak into the house as well as into the cavity causing damp both inside and outside. This problem is often compounded by differential thermal movement in the gutters. Differential thermal movement is caused by different materials expanding and contracting by different amounts as the temperature changes. Such differences have caused the gutter sections to move relative to each other so instead of providing a smooth run for water, linings become damaged and water can sit in the gutters which also leads to dampness in the cavity walls and the concrete deteriorates over time. Thermal bridging or bridging cold has become a major problem with concrete finlock gutters due to central heating and double glazing being installed in homes. As a result the average temperature inside properties is now higher than in the past.
The bridging cold manifests as a black mark where the ceiling meets the wall, where the wallpaper is coming away at the top, as well as in bathrooms where tiles are dislodged.
In the summer it is not as great a problem but in the winter when the heating is on and the finlock gutters become very cold and moisture in the warm interior air condenses on the wall in the vicinity. This leads to cracking, mould and damage to the decorations.
The problem is caused as follows
LINING CONCRETE GUTTERS CANNOT SOLVE THIS PROBLEM
Cutting gutters off does reduce this problem substantially as between the cold and the top of the wall a 22mm wood then a 18mm PVC layer is created.
WHERE GUTTERS HAVE BEEN CUT OFF BY TLG GUTTERS DUE TO THERMAL BRIDGING IT HAS ALWAYS ELIMINATED THE DAMP |
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