Lead neoprene joints
This technical update provides additional guidance on lead neoprene joints. It is important that all workmanship carried out during construction is completed in accordance with the relevant tolerances.
There are a number of materials on the market that can be used to form gutter details such as GRP (glass reinforced fibre), composites (aluminium reinforced polythene), etc. However, lead is the traditional flashing of choice when forming parapet or valley gutters to roofs.
In conservation areas and refurbishment of existing buildings, lead is often the only option. This article looks at the use of neoprene jointing to lead gutters.
Where there are long runs of guttering, it may be difficult to achieve the necessary fall for adequate water runoff. This has traditionally been achieved using a step detail every 1.5m in length.
Recently, with modern building practices advancing, the appearance of a neoprene joint has been brought on the market which removes the step detail and allows for a shallower fall.
The Lead Sheet Training Academy (formerly the Lead Sheet Association) have produced a bulletin entitled ‘Gutter Linings – Traditional or Flexible’ which gives guidance in the use of the two methods.
Fig 1: Traditional stepped detail Fig 2: Neoprene joint lead roll
The neoprene joints are welded to the lead sheets and then covered using clips and a capping section.
Our Technical Manual provides functional requirements for roof flashings in Section 11 - Roofs with detailed guidance in section 11.3, section 11.4 and section 11.5. For warranty purposes, systems must have a third party product approval and be tested to achieve a minimum of 15 years durability.
The use of neoprene jointing is relatively new to the market and at the time of writing this article, we are not aware of any third party independent testing carried out to assess its durability, therefore, the use of these systems do not currently meet our Technical Standards.
Figure 3: Neoprene jointing
Every care was taken to ensure information in this article was correct at the time of writing (March 2021). Guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant building regulations or applicable technical standards. For the most up to date LABC Warranty technical guidance please refer to your risk management surveyor and the latest version of the LABC Warranty Technical Manual.