Liquid roofing? Sounds like something out of a sci-fi flick, doesn’t it?
The term probably brings up an image of unburstable water balloons used as roofing membranes, but liquid roofing is a lot less skiffy than it sounds.
So, what exactly is liquid roofing? How does it work? And what sets it apart from other roofing systems? We address these questions and more in this guide, so stick around.
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Overview of Liquid Roofing
Liquid roofing is an advanced polymeric roofing system that’s applied in liquid form to warm and cold roof designs to protect and waterproof them.
The material doesn’t stay in liquid form for long, though. It becomes touch-dry through moisture in around 1-2 hours and fully cures in 3-5 days, forming a seamless and waterproof membrane.
Liquid roofing is quite versatile in that it can be applied to a wide range of materials, from asbestos and metal to felt and concrete. It’s also suitable for both sloped and flat roofs.
Liquid roofing systems can last up to 30 years with good maintenance. That said, extreme weather conditions and heavy foot traffic may knock off a few service years.
Origin of Liquid Roofing
Liquid roofing isn’t a novelty. The concept dates back to the early 18th century when bitumen was combined with other materials for roof waterproofing purposes.
The concept evolved over the years and became commercial in the early 20th century, with materials like acrylics and unsaturated polyesters coming onto the scene.
The 1970s and 1980s are particularly noteworthy because they introduced not only the first elastomeric liquid roof coatings but also the first single-component moisture-cured polyurethane coatings.
Fast forward to today, liquid roofing is now a staple of the commercial roofing industry, with numerous liquid-applied roofing solutions available on the market.
Membrane vs. Coating
Liquid membrane roofing systems shouldn’t be confused with liquid roof coatings. People sometimes use the two terms interchangeably, but they’re actually different.
A liquid roofing system or membrane is a comprehensive roofing solution that consists of several layers. It’s thicker and more durable than a liquid coating. It’s also backed by a long-term manufacturer warranty.
Per contra, a liquid roof coating is a thin layer of roofing material that helps prolong the roof’s life and resistance to moisture. It’s basically a short-term roofing solution.
Common Types of Liquid Roofing
Now that you know what liquid roofing is all about and how far it dates back, let’s briefly discuss the most common types of liquid roof systems on the market.
PMMA stands for polymethyl methacrylate. It’s an acrylic resin applied to roof surfaces in liquid form using a roller or squeegee. It’s known for its fast curing time and high durability.
This liquid roofing material can tolerate a wide range of temperatures. It’s especially suitable for roofing properties that experience freezing temperatures.
PMMA is solvent-free and highly resistant to chemical corrosion and water pooling (ponding). It’s typically applied with reinforcing polyester fleece for reduced cracking and a prolonged lifespan.
Polyurethane is similar to PMMA in that it’s durable and quick to dry. The difference is that PMMA is an acrylic plastic, while polyurethane is a synthetic polymer.
When combined with a top coat and some non-slip aggregate, polyurethane’s waterproofing properties can handle medium-to-heavy foot traffic. It’s generally low-maintenance and wallet-friendly.
Liquid-applied roofing systems that utilize a silicone membrane are durable and inexpensive. They can also handle extreme weather and temperature conditions without any problems.
Silicone liquid proofing is best for flat and low-slope roofs. It bonds well with a range of materials, including metal and concrete, without needing a primer.
There are a few downsides to silicone systems, though. They tend to accumulate a lot of dust and debris quickly. Also, their surfaces can be slippery and unsafe when moist.
While not as widely used as PMMA or polyurethane, butyl rubber has a few things going for it. Namely, it has a high tensile strength and can accommodate thermal movement—as in expansion and contraction.
Butyl isn’t the most common choice for roofing because it needs a lot of liquid material to reach the desired dry film thickness. This can be attributed to its low solid content.
Acrylics are some of the easiest waterproofing materials to work with. They’re also budget-friendly and offer superb UV and mildew resistance. They do come with a few caveats, though.
Since acrylics are water-based, they lose their effectiveness to ponding. On that account, they’re not a good choice for flat or low-sloped roofs. They’re also not suited for sloped roofs with poor drainage.
More importantly, acrylics tend to lose their thickness over time, which affects their waterproofing and UV protection. On top of that, they’re difficult to install when the temperature is low because they get brittle.
Benefits of Liquid Roofing
So, why should you choose liquid membrane systems? Here are a few reasons why:
- It’s safer and easier to install than most other roofing materials.
- There’s no need to strip existing waterproofing layers if your roof is structurally sound.
- Smooth and seamless finish across the entire surface of the roof.
- Highly resistant to thermal fluctuation, foot traffic, and building movement stress.
- It’s lightweight, so it won’t stress your underlying roofing system.
Liquid roofing is one of the most cost-effective ways of waterproofing new or existing roof surfaces. It can last up to 30 years if installed and maintained properly, and it costs significantly less than other roofing methods.
Interested in a liquid roofing installation? Go ahead and book your free roof inspection!