When it comes to flat roofing, EPDM (Ethylene Propylene Diene Monomer) has established itself as one of the most reliable materials for both residential and commercial properties. Its durability, cost-effectiveness, and ease of installation make it an attractive option for homeowners seeking long-term protection for their roofs. But to fully capitalize on these benefits, knowing the correct EPDM roofing installation process is crucial and you stand to enjoy up to 50 years of service with minimal maintenance.
In this guide, we will walk you through each stage of installing an EPDM roof, from preparation to ensuring proper adhesion and finishing the edges.
Why Choose EPDM for Your Roof?
EPDM rubber roofs are a popular choice for flat or low-slope roofs due to their exceptional weather resistance and flexibility. The material can withstand extreme temperatures, UV radiation, and moisture, making it ideal for areas prone to variable weather conditions. Additionally, EPDM is lightweight and cost-effective, which reduces installation time and costs. With proper installation, EPDM roofs also offer significant energy efficiency by reflecting heat and reducing cooling expenses.
Given its high durability and relatively low maintenance needs, EPDM roofing is an excellent choice for long-term investments in your property’s roof. However, the success of your EPDM roof depends on how well it’s installed.
Preparing the Roof Deck for EPDM Installation
Before beginning the installation process, the first critical step is ensuring that the roof deck is adequately prepared. EPDM membranes need a clean, smooth surface for optimal adhesion. Start by removing any existing debris, dirt, dust, and loose materials from the roof. This step is vital because any moisture or imperfections can cause the membrane to adhere incorrectly, resulting in bubbles or poor performance over time.
Ideally, EPDM membranes should be installed on a timber deck such as exterior-grade plywood or OSB3. If there is any residual bitumen from a previous roof installation, it must be either completely removed or over-boarded, as bitumen can interfere with the membrane’s adhesive properties. A smooth, dry surface ensures that the membrane will properly bond to the roof deck, creating a long-lasting waterproof seal.
Installing the Drip Batten
Once the roof deck is prepared, the next step in the EPDM roofing installation process is installing the drip batten. This is essential wherever a gutter is present. The drip batten extends the roof deck slightly beyond the edge, ensuring that any rainwater will properly drain into the gutter system rather than running behind it. Proper water drainage is a key factor in prolonging the life of your roof and preventing water-related damage.
The installation of a drip batten ensures that your roofing system remains watertight and functional over the long term. Misplacing or skipping this step can lead to significant problems with water management later.
Laying the Drip Trim Backplate
Next, install the drip trim backplate. The backplate is one of the components of the drip trim system and provides additional support for the roof edge. When installing, use the nails provided, ensuring that the backplate is aligned correctly with the timber batten. The curved top edge of the trim should match up with the batten to create a seamless connection between the roof surface and the edge.
The drip trim plays a vital role in keeping water from seeping behind the fascia and into the structure of the building. This added level of protection ensures that your roof remains secure even in heavy rains.
Relaxing the Rubber Membrane Before Installation
A crucial step in any EPDM rubber roofing project is allowing the rubber membrane to relax before adhering it to the roof deck. After laying out the membrane on the prepared deck, leave it for about 30 minutes. This process allows the rubber to settle and any creases to smooth out naturally, reducing the risk of wrinkles or uneven surfaces during installation.
While this may seem like a minor step, relaxing the membrane prevents air bubbles or folds from forming, ensuring a smooth, watertight finish. Without this, the roof may experience premature wear and tear due to uneven adhesion.
Applying Deck Adhesive
After the membrane has relaxed, fold it halfway back to expose the roof deck. At this stage, apply the water-based deck adhesive using a paint roller. It’s important to leave about a 150mm gap around the perimeter, which will later be bonded with contact adhesive. The key to a successful adhesive application is working quickly—ensure that the membrane is rolled back into position while the adhesive is still wet. If the adhesive dries out before the membrane is relayed, reapply a thin coat to ensure proper bonding.
Adhesives used in EPDM installations are weather-sensitive, so they must be applied when the outside temperature is 4°C and rising. Extreme cold can prevent the adhesive from setting correctly, impacting the roof’s long-term durability.
Securing the Membrane and Removing Air Bubbles
Once the membrane is rolled back into place, it’s crucial to sweep the surface to remove any trapped air. Air pockets under the membrane can lead to bubbles and weak spots, which could compromise the roof’s performance. Use a broom or sweep with light pressure to smooth the membrane and ensure proper bonding with the roof deck.
If properly adhered, the EPDM membrane should sit flush against the deck, with no visible air bubbles or wrinkles. This step ensures that the roof remains watertight and performs as expected under heavy weather conditions.
Applying Contact Adhesive to the Roof Perimeter
Once the deck adhesive is applied and the membrane is secured, the next step is to apply contact adhesive to the perimeter of the roof. This adhesive will bond the EPDM membrane to the edges and any vertical upstands, such as parapets or walls. Use a paint roller or brush to apply a thin layer of contact adhesive around the 150mm un-bonded perimeter area of the roof deck and onto the back of the EPDM membrane.
Allow the contact adhesive to become tacky and touch dry before proceeding. It’s important to avoid puddles or uneven areas, as these can result in bubbles or improper adhesion. Once the adhesive is touch dry, press the membrane into place to secure it. Using a roller to apply pressure ensures a firm bond and prevents air from being trapped.
Securing Roof Corners and Trim Installation
When installing EPDM, attention to detail is especially important around corners and edges. Fold the membrane carefully around roof corners without cutting, which helps maintain the roof’s integrity. Pinch the excess membrane together to form what’s called a “pig’s ear,” then fold and secure it onto the side of the roof.
After the membrane is properly positioned, install the edge trim. The trim not only provides a finished appearance but also deflects water back onto the roof, preventing moisture from seeping behind the membrane. Use polypins to secure the trim and ensure that the foam sealer is compressed to about 70-80% of its thickness, creating a watertight seal.
Final Trimming and Inspection
Once the membrane is in place and the trims are installed, trim any excess rubber membrane to create a neat finish. Ensure that all joints, corners, and edges are properly secured, and that the membrane lies flat with no bubbles or gaps.
Finally, perform a thorough inspection to check for any imperfections or areas that need adjustment. With proper installation, your EPDM roof will provide long-lasting protection for your home, requiring minimal maintenance throughout its lifespan.
Ensure Your Roof’s Longevity!
Monastery Roofing LLC has over 15 years of experience installing durable, high-quality roofing systems. Whether you need a new EPDM roof or roofing repair services, we deliver exceptional results that last. Our expert team ensures every roof is installed with care and precision, providing you with peace of mind and long-term protection.
