Key Takeaways
- Match the coating to the surface, not to a price. Substrate, how much water the surface sees, whether it moves or cracks, sun exposure, and foot or vehicle traffic all narrow the options. Surface prep matters as much as the product, since the right coating over a failed or contaminated surface still leaks.
- Acrylic is the budget option for sunny, low-traffic surfaces. It’s water-based, so it goes on easily, dries fast, and runs low in VOCs. It holds up to UV without breaking down. It won’t bridge larger cracks, has poor chemical resistance, and isn’t strong enough for heavy foot traffic or a garage floor.
- Polyurethane is the flexible one for concrete. It soaks into concrete pores to cut absorption, stretches enough to bridge even large cracks, and handles chemicals, heavy traffic, and temperature swings. The tradeoffs are cost, a long cure time, difficult installation, and high VOCs that require good ventilation.
- Silicone is built for flat commercial roofs. It tolerates standing water without breaking down and reflects roughly 90% of sunlight, which lowers cooling load. High solids content means one thick coat. Two catches: it’s dangerously slick when wet, and it attracts dirt, so cleaning becomes part of the maintenance plan.
- Cementitious and bituminous cover the low-cost end. Cementitious is a powder mixed with water, cheap and simple, mostly used to seal basements and crawl spaces, but it’s rigid and prone to cracking. Bituminous membrane is durable, affordable, and self-healing on small cracks, though it’s petroleum-based and tricky to spread evenly.
Waterproofing is not a one-size-fits-all solution. The right system depends on what you are protecting, the material beneath it, how much sunlight or traffic the surface receives, whether movement or cracking is present, and where the moisture is coming from.
Common waterproofing options include acrylic, polyurethane, silicone, cementitious, and bituminous systems. Each has different strengths and limitations, which means a coating that works well on one surface may not be the best choice for another.
This guide compares five common types of waterproofing coatings and explains where each may be used. If you are dealing with an active water-intrusion problem or need help selecting a system for your property, contact us.
How Do You Choose the Right Waterproofing System?
The best waterproofing option depends on more than the material itself. Before choosing a coating or membrane, consider where it will be installed and what conditions it will need to withstand.
Surface or Substrate
Concrete, masonry, roofing membranes, decks, walls, and below-grade surfaces have different waterproofing requirements. A system should be compatible with the material it is being applied to and the conditions of the existing surface.
Exposure to Water
Consider whether the surface is exposed to occasional rain, recurring moisture, standing water, or below-grade water intrusion. Different waterproofing systems are designed for different levels and types of moisture exposure.
Movement and Existing Cracks
Buildings and exterior surfaces move over time. Joints, transitions, existing cracks, and areas subject to expansion and contraction may require a more flexible waterproofing approach or additional repairs before the waterproofing system is installed.
Sunlight and Weather Exposure
Exterior roofs, walls, and decks in North Texas are exposed to strong sunlight, heat, storms, and changing temperatures. The waterproofing system should be selected with those environmental conditions in mind.
Foot or Vehicle Traffic
A surface that people or vehicles regularly travel across has different durability requirements than a wall, roof, or other area with limited traffic. Decks, walkways, parking areas, and similar surfaces may require systems designed for additional wear.
Surface Preparation
Even the right waterproofing material can perform poorly if the surface is not properly prepared. Existing damage, failed coatings, cracks, contaminants, and moisture conditions should be addressed as part of the waterproofing process.
The 5 Types of Waterproofing Coatings
Most waterproofing coatings fall into five families. They differ in what they bond to, how much movement they tolerate, and how they hold up in direct sun, and those differences decide where each one belongs. The table is the short version. The sections below it go through each type, including where we see it fail on buildings in Dallas-Fort Worth.
| Coating | Where it works best | Where it falls short |
|---|---|---|
| Acrylic | Roofs and walls in full sun that drain properly | Poor chemical resistance, limited ability to bridge cracks, and not built for heavy foot traffic |
| Polyurethane | Decks, balconies, walkways, and other surfaces that take foot traffic | Sensitive to moisture in the surface during application, and some formulations need a UV-stable topcoat |
| Silicone | Low-slope roofs where water ponds after rain | Collects dirt over time, and very little will bond to it later except more silicone |
| Cementitious | Below-grade concrete, foundation walls, pits, and tanks | Standard formulations are rigid, so they crack when the structure moves |
| Bituminous | Foundations and surfaces that will be backfilled or covered | Breaks down in sunlight, so it cannot be left exposed |
Acrylic Coatings
Water-based acrylic waterproof coatings are extremely versatile and can be used in a wide variety of applications. One of the most common uses of acrylic coatings is for areas that receive direct sunlight, as the coating can withstand UV exposure without breaking down or getting damaged.
The ease of application also means it is one of the most cost-effective waterproofing options. Another advantage of acrylic coatings is that they are a more eco-friendly option since most of them contain much lower levels of volatile organic compounds (VOCs) compared to certain other types of coatings.
One issue with acrylic coatings is that they aren’t very chemical resistant. That means this type of coating isn’t a great option for a place like a garage or driveway since it won’t last as long due to chemical exposure. Acrylic coatings also aren’t as strong as most of the other options, meaning they aren’t suitable for places that receive heavy foot traffic. The other thing to note is that acrylic coatings can’t bridge or fill in larger cracks in concrete or other surfaces.
Polyurethane Coatings
Polyurethane coatings are generally considered one of the best options for repelling water, especially on concrete surfaces. This is because polyurethane penetrates deep into the pores in concrete, which greatly reduces how much moisture the concrete can absorb. This type of coating is highly elastic, meaning it is much more flexible than other coatings. The elasticity also makes it a great option for repairing even large cracks in concrete and ensures it is strong enough to withstand heavy traffic.
In general, polyurethane waterproof coatings are one of the most durable options since they are resistant to chemicals and can withstand extreme temperatures and UV exposure. That makes this type of coating an ideal choice for patios, garage floors, and a wide range of other applications.
The main drawbacks of polyurethane coatings are that they are quite expensive compared to most other options and take a long time to dry and cure. The coating is also difficult to install, meaning it needs to be done by an experienced, skilled professional. One other issue is that polyurethane coatings are quite high in VOCs, meaning the coating can only be applied in an area with adequate ventilation.
Silicone Coatings
Waterproof coatings made with silicone are an excellent option if you need help with commercial roofs, especially flat roofs. One reason is that it can withstand water ponding or pooling up on it without degrading or breaking down, which isn’t the case with other coatings such as acrylic. Silicone coatings are an especially great choice for hot climates, as they are highly UV resistant and reflect around 90% of sunlight. That means the coating can help reduce your cooling costs since it will prevent your roof from getting as hot.
Silicone coatings also have a high solid content, which allows the installers to create a thick membrane with just a single coat. That means you save money on the installation costs since the coating can be applied fairly quickly. The high solid content ensures that the coating is quite flexible and extremely durable as well, allowing it to withstand the elements without weathering. Silicone coatings also don’t contain any solvents and are very low in VOCs, making them one of the most eco-friendly options.
One of the main drawbacks of silicone coatings is that they are extremely slippery when wet, meaning they aren’t suitable for areas that receive foot traffic. Another issue is that the coating attracts dirt, resulting in increased maintenance and cleaning requirements. The area must be properly cleaned and prepared before the coating is applied, or else it won’t bond properly and can allow moisture to seep through. You’ll end up with moisture intrusion if the coating isn’t applied thick enough as well.
Cementitious Coating
A cementitious coating is essentially a thin concrete mixture made up of sand, silica and other organic and inorganic materials. The coating comes in a powder that just needs to be mixed with the correct amount of water before applying it. This makes it extremely easy to apply compared to most of the other options. The ease of application and the low cost of the cementitious powder also make it one of the least expensive options.
This type of coating is primarily used for sealing and waterproofing concrete basements and crawl spaces. Although it’s quite rigid and inflexible, it can also be a good option for walkways, patios, driveways, etc. The only issue is that it can be prone to cracking and may not last as long as other options.
Bituminous Membrane
Bituminous membrane is a coating made of a tar-like substance known as bitumen mixed with various other materials such as rubbers or polymers. Sometimes also referred to as liquid asphalt, this coating is commonly used in commercial applications, such as waterproofing a flat roof or sealing the walls and floors of a basement or crawl space.
It’s commonly used for driveways, parking lots and sidewalks as well. The reason it’s so versatile and so popular is that the coating is highly durable and long-lasting while also being quite affordable. It’s even self-healing, meaning that any cracks that form in the membrane will get filled back in fairly quickly.
The primary drawback to this type of coating is that it’s not all that eco-friendly since bitumen is produced from crude oil. Although the coating itself isn’t that expensive, the installation process can be complicated as well. That’s partly because liquid bitumen is highly viscous, meaning it’s sometimes difficult to spread evenly. It also takes more time to prepare the surface before applying the coating to ensure it adheres properly and creates a fully waterproof barrier.
With more than 20 years of professional experience, KPost Company is the company to turn to for all your roof waterproof coating needs. We offer a wide range of commercial waterproofing services, from deck and roof coatings to vapor barriers and below-grade waterproofing.
We also specialize in concrete and masonry repair as well as the full range of commercial roofing services. To schedule a consultation for your Dallas business and learn more about which waterproofing option will best meet your needs, contact us today.
Waterproofing a Commercial Roof
On a low-slope commercial roof, waterproofing means the membrane and every detail that interrupts it. The open field of the membrane is rarely where water gets in. Drains, equipment curbs, pitch pans, pipe penetrations, and the terminations along parapet walls are, and a coating rolled over the field without addressing those details will not stop a leak.
Where the membrane is weathered but the insulation below it is dry, a coating is often the most economical way to extend the life of the roof. We cut core samples before recommending one. Dry insulation means a coating is worth pricing. Saturated insulation means a coating would seal the moisture into the assembly, and replacement is the honest answer even though it is the larger number.
The choice of chemistry follows the drainage. Roofs that hold water after rain need silicone, because standing water breaks down acrylic. Roofs that drain properly can take acrylic, which costs less. In both cases the preparation decides how long the coating lasts, and cleaning the surface and reinforcing every seam and penetration before the coating goes down matters more than which brand is on the bucket.
FAQs
Traffic-bearing coatings are the most demanding application of the five, and this parking garage at Signature Exchange shows why:
