What is Finlock Guttering?

Posted on Monday, December 31, 2018

Most people haven’t heard about Finlock gutters. So, when they hear the term, they ask themselves what this kind of guttering is this. If you’re one such individual who hasn’t come across this kind of guttering, this piece should hopefully enlighten you. Finlock gutters are a system of guttering made of concrete. They’re usually found in properties that were built between the 1950s and the ’70s.

The purpose for which Finlock gutters were introduced

These gutters were formally introduced as a replacement to cast iron guttering systems. This is because there was a shortage of steel at the time. Hence, concrete was logically a durable and low-cost alternative to steel. Furthermore, cavity constructed walls were becoming more common at the time and Finlock gutters served to close the top of the cavity walls. They could also be used as load bearing for openings where doors and windows were placed.

The composition of Finlock gutters

A Finlock gutter is built from two troughs that are horizontally positioned and sit at the head of a cavity wall. One of the troughs serves as the gutter while the other one distances the gap between the walls, also known as the cavity. This cavity sits on the internal wall. The Finlock blocks were varied in length, typically between 200 and 250 mm. These blocks were connected to one another using steel which was reinforced with mortar and rods. The sealing was then done, and the troughs were lined with a coating of bitumen or any other waterproof material, alternatively the lining was done using a mineral felt.

finlock guttering

 

Finlock gutter problems

Lining failure

The main cause of failure in these gutters is that resulting from expansion and contraction of the lining as a result of changes in temperatures. However, there many other causes of this problem as the thermal changes lead to the separation of weak points or at the junctions. As a result the heavy inflexible troughs of concrete often crack leading to points through which water can enter. This kind of failure should be addressed immediately because it can be extensive.

Cold/thermal bridging

Cold bridging is when cold materials meet warmer ones resulting in the cooling down of the warmer material. This often presents as horizontal grey bands at high levels of the perimeter walls. When there’s such a problem, the wallpaper can begin to peel away at the top of your wall. If the wall is tiled, the tiles could start to become slightly raised.

Sagging and uneven gutters

These gutters act as door and window opening lintels. However, without adequate filling or strengthening when they’re fixed, they can sag slightly. Sagging can also result from poorly replaced windows, such windows become difficult to close or open.

Solutions to Finlock gutter problems

The problems associated with these gutters can be removed through either complete replacement or relining and repair, the former option is costlier. The relining and repair options are a short-term solution, it’s often done using a waterproof material.