What to Avoid With Roof Membranes

When sourcing roofing materials, there are a number of things to avoid. Here we’ve delved into the two most common issues to help raise the roofing standard...

Date: 2021-10-01

Author: Klober

Category: Industry Topics

Tags: Membranes Support Value

When sourcing roofing materials, there are a number of things to avoid. Here we’ve delved into the two most common issues to help raise the roofing standard:

1. Focusing on Cost Per Unit

Taking a price-led approach per unit cost can create a false economy for a building project. The true cost of quality roofing is relative not only to the price, but to the performance and how long it will last. Simply, a slightly higher investment up front can translate to savings in terms of both time and money later into the product’s life. What’s more, the longevity and protection that a secure, weatherproofed, and well-ventilated roofing system provides, cannot be undervalued.

A quick online search shows many reports of cases where new or recently installed roofs are leaky and dangerous, or even falling apart. This is concerning as a good roofing system should last for decades with routine maintenance. If a roof degrades prematurely, within the first year, then the housebuilder or roofing contractor may be responsible for making repairs. As such, choosing products that are built to perform will make a difference to the overall quality and longevity.

Both breathable and non-breathable membranes provide the essential barrier needed to protect the property from unexpected water ingress. Breathable options have less vapour resistance so that water vapour can exit freely and, in some cases, without the need for separate ventilation above the roofing insulation.

Whether it is a cold or warm roof, products with a higher price tag may have test data to bolster claims of strength, permeability and durability. To this end, Klober invests in rigorous product testing to ensure that membrane roof coverings meet the requirements they claim.

Testing also allows products to be verified by trusted industry bodies. For roofing membrane types without additional ventilation, the National House Building Council (NHBC), will only accept third party approved air open membranes. This includes Permo Air, which is British Board of Agrément (BBA) approved for both cold and warm roofs without the need for additional ventilation.

Given that not all membranes and barriers suit all applications, low pitch roofing felt must be selected for low pitch applications, for example. Choosing the correct low pitch roofing membrane is important because the roof may otherwise fail.

2. Not considering the UK climate

When selecting a breathable roofing membrane, UK weather and climate requires more robust roofing components. Extremes in temperature and weather mean waterproof membranes for roof projects, vapour permeable roofing membranes and non-permeable membranes are valuable additions to any roofer’s portfolio.

One of the key challenges is condensation. Modern buildings are designed to be as energy efficient as possible, in line with building regulations and environmental targets, meaning new homes tend to be more air tight. With people spending more time at home, there is a greater risk of condensation. Specifically, this is linked to the tendency to heat the home for longer periods and at higher temperatures, with weather events impacting this.

Therefore, selecting breathable vapour membranes like Klober’s Permo Air, which does not require additional ventilation, means condensation risk is minimised. Klober champions breathable membrane technology as a high-performing technology, with the most breathable being known as a air open or air permeable roofing membrane.

Other components such as roofing membrane tapes, also known as breather membrane tapes, should also be considered. The membrane tape selected should be compatible with the roof tile underlay chosen, as not all tapes are made equally, or a product with an integral adhesive tape can be considered.

Vapour Control Layers are also available and, when installed on the warm side of the insulation, are an effective way of controlling the passage of water vapour to reduce the risk of condensation in the roof space.

For more information on Klober’s full range of membranes and barriers, click HERE.