Does Your Membrane Roof Need Repairing Or Replacing?
Do you have a membrane roof with insulation, stability, or drainage issues? Is your membrane roof old and worn and in need of some loving care?
Here we’ve put together an Membrane Roof Guide to give you more information about this specific roof type …
JP Franklin Roofing Membrane Roof Guide
Overview of Membrane Roofs
Membrane roofing is a type of roofing system for buildings and tanks. It is used to create a single layer watertight roof covering to protect the interior of a building. Membrane roofs are most commonly used in commercial application, though they are becoming increasingly common in residential application.
Membrane roofs are the perfect option if you have a flat roof or low sloped roof. At JP Franklin, we install, repair, and replace Membranes roofs. We have a range of high-quality, latest technology options to choose from including EPDM (Ethylene Propylene Diene Monomer) and butanol roofs, so you get the best Membrane for your budget and the size, location, and style of your roof.
A Bit of History About Membrane Roofs
The original solution for flat roofs about 120 years ago was the Built Up Roof (BUR) which involves several layers of a special type of roofing felt that has been impregnated with asphalt and embedded in bitumen applied with a hot mop. Modified bitumen was developed in the late 1960s to replace BUR using similar technology but adding polymer reinforced roof wear layers or cap sheets to provide improved elasticity and flexibility in lower temperatures.
The latest products of rubber and synthetics began to appear in the 1950s with the boom of the rubber and plastics industries.
In 1966, a German company, called Trocal, formulated and produced the first known PVC roofing Membrane. PVC is one of the pioneering single-ply roof materials that was specifically designed to address a wide range of roofing problems resulting from water leaks. PVC’s superior performance to other flat roofing systems were quickly recognised, and within a few years, Trocal’s PVC roofing Membranes covered millions of square feet all over Europe and the use of PVC Membranes started spreading across the world.
EPDM single-ply rubber roofing Membranes were first introduced in the early 1960s. It was cost-effective and simple to install, and quickly became known for its exceptional hail resistance, UV stability, and weathering resistance due to the cross-linked nature of its chemistry and the UV-absorbing power of its raw materials.
Since its introduction, numerous enhancements have been made to the system components, making today’s EPDM systems far more robust and a greater value than ever before. This single-ply rubber roofing Membrane is still one of the most appealing choices for the flat roof and low-slope commercial roofing industry 40 years later.
For more information about EPDM, visit the EPDM Roofing Association Website.
Membrane Roof Materials and Varieties
There are different types of Membrane roofs and it’s important to check with your roofing contractor to find out exactly which material they plan to use.
The major types of Membrane roofs offered today are: thermoset (EPDM), thermoplastic (PVC or similar material), modified bitumen, glass reinforced plastic (GRP), and liquid ‘paint-on’ roofing.
EPDM is perhaps the most popular Membrane roof these days and, with the latest advancements in technology, has redefined the flat roofing industry. Its two primary ingredients, ethylene and propylene, are derived from oil and natural gas.
Thermoset Rubber Membranes
These materials are ones that chemically crosslink. This means that once seams cure they form one giant ‘molecule’ of roofing. Many of the synthetic rubber roofs such as EPDM (an elastomeric rubber supplied as a roll or sheet with vulcanised joints) and butyl (a synthetic rubber supplied as a roll or sheet with vulcanised joints) fall into this category (you also find the CSPE, CR, and ECR compounds/membranes in this group). These membranes are fairly thick and often in thicknesses of between 30 and 60 mils. EPDM withstands foot traffic well and should last for at least 40-50 years if well-installed and well-maintained.
Thermoplastic Rubber Membranes
These membranes are very similar to the thermosets, but there’s no chemical cross-linking or vulcanisation. Seams in the materials are welded together with solvents or heat. This category includes PVC (polyvinyl chloride), TPO (thermoplastic polyolefin), and TPE (thermoplastic polyolefin elastomer). Lifespans vary depending on the material but for a general idea PVC can last for up to 50 years, TPO 20 years, TPE 30 years, and PIB 30 years plus.
Modified Bitumen Felt Membranes
These Membranes combine asphalt with modifiers and reinforcement materials, including polymers such as APP and SBS (both modified bitumen with a mineral/ceramic chip, metal foil or acrylic coating). The bitumen-coated felt comes in a roll and is applied in two or three layers. It is supplied either in self-adhesive rolls or a blow-torch is used to melt the bitumen as it is laid out, bonding it to the roof. Felt is the most economical option for a flat roof, but also the least durable and it can be easily damaged. It comes in a very limited range of finishes and is not easily repaired to a high aesthetic standard, so is best used on roofs that will be hidden from view. Although these materials can perform well, they are not as advanced as other newer materials so more prone to leaking.
GRP (Glass Reinforced Plastic) Fibreglass Roof
This is a waterproof resin used to create a seamless roof covering. Originally used in the boat-building industry, modern GRP designed specifically for roofing is extremely durable and resistant to damage, with a life expectancy of 50 years or more. Most companies offer a 25-year guarantee for these but they are known to last longer if well-maintained.
Liquid or Paint-on Roofs
Liquid roofing is the process of waterproofing a roof by the application of a specialist liquid roof coating. It is suited to all types of roof, including flat, pitched, and domed. Liquid roofing involves the application of a monolithic, fully bonded, liquid based coating to a roof.
The coating cures to form a rubber like elastomeric waterproof membrane, capable of stretching and returning to its original shape without damage. Such coating systems are usually reinforced with secondary materials such as glass-reinforced plastic to provide additional tensile strength. The coatings can be applied over most traditional roofing materials, including felt, asphalt, bitumen, and concrete.
See our partner Viking Roofspec for some examples of Membrane roof options.
How Long Does a Membrane Roof Last?
For general guidance, modified bitumen EPDM is considered to last 25-30+ years, PVC 20+ years, and TPO 15+ years, GPR 50+ years. However, the longevity of a roof is dependent on many factors such as climate, installation, system type, roof penetration, and proper maintenance. It could last as little as 10 years or up to 50 years and more.
This means that choosing a trusted specialist installer who can advise the best materials for your conditions is extremely important.
You should also make sure there is proper drainage and check the seams, flashings, and all around the rooftop penetrations periodically and after rainstorms.
Benefits of Membrane Roofs
- Fatigue resistance
- Proven hail resistance
- High resistance to ozone, weathering, and abrasion
- Resistant to some chemicals found on roofs such as acids and alkalis
- Flexibility in low temperatures
- Superior resistance to extreme heat and fire
- Thermal shock durability
- Ultraviolet radiation resistance
- No seams so less prone to leaks
- Relatively easy to install
- Versatile application methods – able to create a design using EPDM for any roof shape, slope, height, and climatic exposures
- Low lifecycle costs
- Reduced labour costs
- Long-term warranties
- Resistance to moisture, wind, fire, and chemicals
- Energy efficient
- Relatively eco-friendly
- Long lifespan
- Flexible membrane allows it to withstand punctures, tears, and impact damage
- Eco-friendly (heat-reflective)
- Relatively low-cost
- Resistant to bacteria, debris, algae, and dirt
- High seam strength
- Quick and simple to install
Modified Bitumen Felt
- Low cost
- Proven results
- Suits roofs of any size
- Hard wearing
- Long lifespan
- Seamless waterproof membrane
- Versatile – reaches the parts other membranes can’t
- High elasticity and film strength
- Easy to maintain
- Relatively quick to install
Common Issues With Membrane Roofs
One issue with rubber Membrane roofs is leaking and ponding of water. These are caused by poor design and/or installation as well as a lack of maintenance. IT is important you choose your roofing company carefully and make sure they are highly qualified and experienced.
Another issue with rubber Membranes is punctures. Tradespeople traffic on the roof can cause scrapes/cuts in the membrane and damage to the underlying substrate. One thing that can be done to avoid this issue is to add walkway paths or extra sacrificial layers of membrane.
Older EPDM roofs or modified bitumen membranes can experience shrinkage due to ageing of the material, poor installation, and UV exposure. The main concern is that it can pull at flashings, leading to splits and cracks that allow moisture in. A few decades ago, unreinforced rubber roof systems were plagued by shrinkage problems, but thanks to technological advancements and improvements to EPDM roofs, the problems have diminished.
To prevent this issue with modified bitumen/asphalt, roofing contractors should lay out the material to relax for 45 minutes, then when installed, alternate/stagger end laps. On an EPDM roof, the use of ballast or a coating can prevent UV from heating the membrane and causing shrinkage.
If you are already experiencing this problem with your roof, it can be repaired by cutting the flashing, securing the field sheet with a termination bar or RUSS strip, and installing a new flashing.
Let Us Help You With Your Membrane Roof Needs
Contact us at JP Franklin Roofing on 0800 456888 (or complete the form below) for professional advice and/or a competitive quote for your Membrane Roof installation, maintenance, repairs, or replacement. We provide top quality craftsmanship at affordable prices.