Ventilation Matters: DIY EPDM Roof Venting

EPDM is world-renowned for its durability, flexibility and resistance to weathering. However, much like any roofing system, its performance and lifespan heavily depend on the substrate quality beneath. 

This is where roof venting is a key factor, as a lack of moisture control and temperature regulation can damage the substrate, which will eventually take its toll on the EPDM system. 

To ensure the longevity of both your DIY EPDM roofing system and your substrate, we always recommend that your flat roof ventilation is taken into account.

Why is EPDM Ventilation Important?

Proper roof ventilation for flat roofs is essential for an EPDM system for the following reasons:

1. Temperature Regulation
   Effective ventilation helps regulate the temperature within the roof space. EPDM has exceptional thermal properties, however due to EPDM being a “glue-on” solution, extended periods of heat exposure can begin to wear away the adhesive, leading to flapping or bubbling underneath the EPDM membrane.
   
   This also has environmental impacts, as the retaining of heat will lead to greater energy consumption to keep the space cool.
   
   Another aspect impacting the efficacy of the EPDM roof is the possibility of ice dams forming in winter, which can damage both the EPDM system and gutters.

2. Moisture Control
   Adequate ventilation helps manage moisture levels in the roof space. If a substrate is exposed to moisture over a long period, the substrate will start to rot, causing potential structural damage and a huge reduction in the integrity of the EPDM system. 

Air quality
Long-term moisture exposure in a roof space can lead to mould forming, which poses a major health risk and has a detrimental effect on the air quality.

Steps which can be taken to improve EPDM roof ventilation

1. Soffit Vents - Soffit vents are intake vents located under the eaves of the roof. These vents allow fresh air to enter the loft space, and ensure ample airflow, reducing the likelihood of moisture buildup.

2. Ensure proper insulation - properly installed installation is essential in reducing the risk of heat transfer, resulting in condensation. 

Frequently Asked Roof Ventilation Questions

Does A Warm Roof Need Ventilation

Warm roofs work to prevent moisture from forming on cold surfaces on the roof. Because of this, warm roofs do not typically require ventilation. However, an air and vapour control layer (AVCL) should be installed on the warm side of the insulation.

How To Ventilate A Cold Flat Roof

The cold deck should have a ventilated cavity of at least 50mm, allowing two opposing vents to allow airflow through the space to avoid the buildup of moisture.

Do Flat Roofs Need Ventilation

If the flat roof has been installed on cold-deck insulation, ventilation is required. 

How Does Roof Ventilation Work

Roof ventilation works by allowing air to flow freely through the space, carrying moisture and condensation out of the space to avoid damaging the roof structure over time.

Conclusion

Roof ventilation on a cold-deck EPDM installation is vital; this will reduce the damage caused by wood rot and mould. We’re always on hand to answer any questions you might have regarding the longevity of EPDM, and offer installation videos, how-to guides & training at our High Wycombe premises.