A penetrating sealer with good breathability protects the floor from flaking and peeling. One with a good water barrier prevents stains from spills. No penetrating sealer is both highly protective and highly breathable. What's the best compromise?
Siloxane has the best breathability combined with reasonable protection from spilled liquids. It is the most likely not to spall (flake and peel) while still resisting stains.
How Liquid Affects the Garage Floor from Above
Anything that spills onto untreated concrete can permanently stain it.
Untreated concrete will suck in spilled coffee or motor oil. Concrete is highly porous, allowing liquid to seep deep within its structure.
A “water barrier” sealer prevents liquid from penetrating the floor surface.
A garage floor protected with a good water barrier seal will resist coffee and oil staining.
A good water barrier is protective because it stops seepage and staining from dropped liquids.
How Moisture Affects the Garage Floor from Below
Trapped groundwater seeping up through the floor can increase the pressure that will cause flaking and peeling.
Untreated concrete sucks up groundwater, especially if it is installed without a moisture barrier under the floor. The natural path of groundwater through concrete is to evaporate through the floor surface.
A “breathable sealer” allows water coming up through the floor to evaporate. A breathable sealer prevents extra pressure in the concrete.
A sealer with no breathability traps the moisture, creates pressure, and leads to spalling (flaking and peeling).
A breathable sealer is protective because it reduces damaging pressure.
How Penetrating Sealers Respond to Water and Vapor
Silicate, silane, siloxane, and silicone penetrating sealers are lightweight alternatives to film-forming epoxy, urethane, polyaspartic, and acrylic sealers.
Penetrating sealers have varying water and vapor response profiles.
| Differences in How Penetrating Sealers Deal with Liquid and Moisture | ||
| Type | Water Barrier Protection | Breathability |
| Silicate | Low to Medium | High |
| Silane | Medium | Medium to High |
| Siloxane | Medium to High | High |
| Silicone | High | Low to Medium |
Silicone is the most waterproofing penetrating sealer, followed by siloxane, silane, and silicate.
Silicate and siloxane are the most breathable penetrating sealers, followed by silane, and then silicone.
Siloxane has the best breathability combined with reasonable protection from spilled liquids. It is the most likely not to cause problems while still resisting stains.
If a penetrating sealer is not good at protecting the floor from spills, why even use it?
How to Balance a Sealer's Benefits with its Drawbacks
The moisture response of sealers is just part of the decision of which sealer to buy.
If your garage floor needs breathability because it's prone to sucking up water from underneath, then you must get a breathable sealer. The cons of that type of sealer will come along for the ride.
That's why I made this table that gives you the best features as well as issues with each type of sealer.
First, decide what you must have. Then decide among those sealers that have that feature.
For my money, the biggest must-have is breathability if there's any chance the floor will soak up groundwater. If that is positively not an issue for you, then you have more options.
For the table below, this is how I rate the sealer types on durability, protection, adhesion, appearance, and breathability.
Note that these are generalities! Any individual sealer might lie outside these guidelines!
- Durability refers to the sealer's resistance to wear and tear over time.
- Protection indicates the sealer's ability to protect the concrete from water, salts, and other potentially damaging substances.
- Adhesion refers to the sealer's ability to bond with the concrete.
- Appearance indicates the change in the concrete's look after the sealer has been applied.
- Breathability refers to the sealer's ability to allow water vapor to escape from the concrete.
| Penetrating Sealer Qualities to Judge Before Buying | |||||
| Sealer Type | Durability | Protection | Adhesion | Appearance | Breathability |
| Silicate | High | Medium | High | Natural | High |
| Silane | Medium-High | High | Medium-High | Natural | Medium to High |
| Siloxane | Medium-High | High | Medium-High | Natural | High |
| Silicone | Medium | Medium-High | Medium | Glossy | Low to Medium |
Benefits and Problems of Silicate Sealers
On the happy side, silicate sealers are great for hardening the floor and reducing dust. On the unhappy side, they
Why You Might Want a Silicate Sealant
Silicate sealers penetrate into the concrete and react with it to form a hard, dense layer. This can strengthen the surface of the concrete, making it more resistant to abrasion. And since untreated garage floors are naturally dusty, a silicate sealer stops that fine film of dust that settles on everything in a garage.
Silicate sealers are breathable, meaning they allow water vapor to pass through. This can help prevent problems such as spalling due to trapped moisture.
Silicate sealers are usually very durable because they react chemically with the concrete and aren't just a surface coating. This means they can't peel or flake off and don't need to be reapplied as often as some other types of sealers.
Silicate sealers typically don't change the appearance of the concrete much, because they're not a surface coating. They can sometimes darken the concrete slightly, but they don't leave a glossy or wet look.
Why You Might Regret a Silicate Sealant
Silicate sealers aren't as effective as some other types of sealers at resisting stains from oil, grease, or other common garage substances. If staining is a concern, a different type of sealer may be a better choice.
While silicate sealers can provide some resistance to water penetration, they're not fully waterproof. If water issues are a concern, a waterproofing sealer might be necessary.
Silicate sealers require the concrete to be properly prepped and cleaned to ensure a good reaction. This may require additional steps compared to some other types of sealers.
A silicate sealer will not provide a shiny, glossy finish, something that some people prefer. They generally leave a natural matte finish.
Benefits and Problems of Silane Sealers
Sealing a garage floor with a silane sealer also has a number of pros and cons, depending on the specific needs and circumstances of your garage.
Why You Might Enjoy a Silane Sealer
Silane sealers penetrate deeply into the concrete, helping to provide protection below the surface.
Silane sealers are hydrophobic, meaning they repel water effectively. This can be beneficial in a garage setting where the floor might be exposed to water, such as from rain or snow tracked in on vehicles.
Like silicate sealers, silane sealers are breathable, allowing water vapor to escape. This helps prevent issues like efflorescence and spalling.
Because they penetrate into the concrete, silane sealers don't wear off the surface as quickly as some other types of sealers. They can provide long-lasting protection.
Silane sealers generally do not significantly change the appearance of the concrete. They do not leave a film or gloss on the surface.
Why A Silane Sealant Might Not Work for You
Silane sealers offer limited stain protection from things like oil and grease.
Silane sealers require excellent preparation before application. They might require more effort compared to some other sealers.
Silane sealers can be more expensive than some other types of concrete sealers.
A silane sealer will not provide a shiny or glossy surface.
Benefits and Problems with Siloxane Penetrating Sealers
Siloxane sealers can be a good choice for garage floors as they offer a unique combination of benefits and have a few potential drawbacks.
How Siloxane Sealers Work for Your Floor
Siloxane sealers are excellent at repelling water. They create a hydrophobic barrier that helps to keep water and other liquids from penetrating the concrete. This can be particularly beneficial in a garage environment where the floor may be exposed to various liquids.
Despite providing good water repellency, siloxane sealers are also breathable. They allow water vapor to escape from the concrete, which helps to prevent issues like efflorescence or spalling that can result from trapped moisture.
Like other penetrating sealers, siloxanes penetrate into the concrete to provide protection below the surface.
Siloxane sealers tend to last longer than some other types of sealers because they penetrate into the concrete and don't wear off the surface as quickly.
Siloxane sealers typically do not alter the appearance of the concrete significantly. They don't leave a glossy or wet look.
Why You Might Regret Siloxane Sealer
Siloxane sealers do not provide high-level protection against oil and other stains.
The concrete must be properly prepared and cleaned for the siloxane sealer to be effective. This may require additional effort compared to some other types of sealers.
Siloxane sealers do not alter the floor appearance, or offer a glossy look.
Benefits and Problems with Silicone Penetrating Sealers
Silicone sealers offer a unique set of benefits and drawbacks when applied on garage floors.
What's Good about Silicone Sealers
Silicone sealers can provide excellent water resistance, protecting your garage floor from water damage.
Silicone sealers can provide good resistance to oil, grease, and other substances, making them a good choice for garage floors where these types of spills are common.
Silicone sealers are generally easy to apply compared to some other types of sealers.
Depending on the product, some silicone sealers can enhance the appearance of the concrete, providing a gloss or “wet look” finish that some people prefer.
What's Not as Good About Silicone
Silicone sealers, especially those that form a film on the surface, may not be as breathable as penetrating sealers like silicate, silane, or siloxane sealers. This could potentially lead to issues with trapped moisture.
While silicone sealers can provide good initial protection, they may not last as long as some other types of sealers, particularly those that penetrate into the concrete. They may require reapplication more frequently.
Depending on the specific product and application, a silicone sealer might make the floor more slippery, especially when wet. Some products might include additives to help improve traction, but this is something to be aware of.
While some people prefer the gloss or wet look that a silicone sealer can provide, others might prefer the more natural appearance of the concrete. The change in appearance could be a drawback if you prefer a more natural look.
Conclusion
A garage floor prone to moisture from below requires a breathable sealer or trapped moisture will cause flaking and peeling. Silicate and siloxane are the most breathable penetrating sealer types. Siloxane has the best breathability combined with reasonable protection from spilled liquids.
Help With Your Garage Floor
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