Finlock Type Concrete Gutter Aluminium Liner Installations:
In order to stop water penetrating buildings through concrete "Finlock" type Gutters, it is necessary to provide a watertight and extremely durable lining to the water-carrying channel. "Finlock" Gutters were installed, as standard, on many large-scale house building projects from 1945 onwards, in an attempt to provide an alternative to traditional wooden or iron guttering; both materials being in very short supply after the Second World War. It has become apparent that water is penetrating vast numbers of dwellings via the concrete "Finlock" gutters and causing serious structural defects.
Finlock type concrete gutter
In an attempt to stop the water penetration problem very many of these gutters have been treated, often several times, with bituminous applications and, in some cases, with roofing felt linings. Whilst offering short term cures, in ideal conditions neither of these methods of water proofing could be expected to provide a long term answer to this most serious problem.
In order to restore the gutter's water carrying capacity it is necessary to remove as much of the previously applied bitumen and felt etc, as possible. The gutter should then be thoroughly cleaned and all debris removed.
On inspection the sarking felt laid under the roof tiling is often found to have perished at the point of it's entry into the gutter. Where this is found to be the case, it is advisable to remove the lower course and a half or roof tiles or slating in order to expose approximately 300mm of sarking felt and slate battening.
Before refixing the battening and after carefully cleaning the "Finlock" guttering, install the Alstream site roll formed Continuous "Finlock" Gutter Liner. By installing the liner at this time the battening and sarking felt can be laid over the aluminium liner back flap thus ensuring that driving rain and snow will always ultimately find it's way into the liner and not into the concrete "Finlock" Gutter and thus into the dwelling.
Finlock Design
Corner units and stop ends are best fabricated and powder coated off site to suit the profile of the liner and then underlying "Finlock" Gutter by Aluminium Roofline Products. The design of these fittings should allow and overlap joint between the fittings and liner of at least 50mm, and sealed by Arbosil 1090/1096 silicone sealant and pop riveting as recommended and supplied by Aluminium Roofline Products.
If water is to be discharged from the liner via the existing down pipe as is normally the case, then the base of the liner should be opened at the outlet point and sealed to the underlying concrete by means of Arbosil 1090/1096 silicone sealant using a soft polythene 60mm outlet fitting provided by Aluminium Rainwater Good, following measurements being taken on site.
