Finlock Background -

The design and construction of domestic properties in the UK has changed over the course of time. The changes have been influenced by styles, availability of materials and statutory policies. Circa 1950 - 1970, deviations from conventional practices saw the construction of system built properties (Cornish units, BSIF, Airey etc), the laying of pitch fibre drainage pipes and, for instance, the use of concrete gutters. These are correctly known as 'Finlock' gutters.

Originally made by the Royston company, Finlock gutters are, in short, small sections precast concrete moulded into two troughs - the inner 'lintel trough' and outer 'gutter trough'. There are three main types, the 'Royston', 'Type G' and 'Type N' (there were 5 designs originally). Finlock gutters are still made today.

The 'lintel trough' should be filled with concrete and reinforcement to form a structural lintel over window openings. The 'gutter trough' projects over the external wall face and receives the rainfall from the roof slopes. Finlocks were constructed on both local authority and private sector homes of the period; aswell as commercial buildings.

Finlock Gutters Ltd offered guarantees if the gutter was lined with hot bitumen over aluminium sheeting over hot bitumen. Example linings found today include bitumen, felt, lead, flashband, fibreglass and others. Linings in poor condition can cause blockages, overspill and internal damage. Downpipes are typically made of asbestos containing materials (ACM's).

As a reaction to differential movement, thermal tension etc, Finlock sections can open up at joints and cause leaks into the cavity and the inner walls of the property. Minor cracking can manifest on internal wall finishes, as a reaction to the stress / strain relationship. Although not common, dislodged sections must be considered for the risk of 'falling elements'. On Royston types, the front 'lip' often dislodges from the Finlock, because it is just a thin decorative fascia piece which is mortared on. The lintel troughs are not always filled with concrete, especially over windows etc, and this can cause instability, movement and displacement of the Finlocks.

Damp and mould can manifest on internal walls as a result of condensation and cold bridging. In short, as a thermal element, the Finlock is cold, especially as it spans from outside your house right into the inner rooms. Thus, it acts as a 'bridge' for the cold, which means the warm, moist air created in the inner rooms, if not adequately removed, will condense on the back of the Finlock. It is not uncommon to see patterns of mould along the tops of inner rooms, behind the Finlock. Damp and mould can cause health conditions, and may be considered a Category 1 hazard under the Housing Health and Safety Rating System.

Today property owners might wish to reline their Finlock concrete gutters or have them totally replaced with PVCu alternatives. Or, one may just require sensitive repairs or new sections of Finlock. Whatever the need, RemFin can help you get the result you require.

Contact us on 0844 561 7660 (7 pence per minute plus your own provider’s access charge).

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