Concrete Sealer: What You Need to Know

Concrete is a sturdy material that’s practical and affordable. In many cases, it can even be quite beautiful. Unfortunately, it’s also an extremely porous material, so using concrete sealer is an absolute must – especially if your concrete is outside.

If you’re a DIY enthusiast who is laying or sealing some concrete for the first time, here’s what you should know before you get started.

What is a Concrete Sealer? 

Concrete sealer is a product that’s applied to concrete to prevent damage. It protects against everything from staining to outright corrosion. It seals the concrete against water, grime and other damaging elements that are present in everyday life. 

Sealers across different brands use a number of different ingredients and formulas, though most are either water-based or petrochemical. There are some sealant bases that are more common than others. These include polyurethane, epoxy, acrylic resins and various silicas. Some sealers can also provide colour enhancement or other appealing visual effects.

Most sealers are easy to apply for a DIY user and can be applied with simple tools like a roller, sprayer or brush, depending on the product that you buy. A good rule of thumb is to apply two thin coats. 

Popular concrete sealer brands in Australia include Chemforce, Environex and Stain Proof. We particularly recommend Stain Proof – they have a huge range of different sealers and have a great reputation for quality.

Why should you use it?

Concrete is very porous, so it’s particularly susceptible to damage and will stain easily. Concrete that’s unsealed will age much faster than concrete that is properly sealed and maintained. This is why it’s so important to apply a high-quality concrete sealer.

All of this is especially true if you live in an environment that regularly gets to freezing temperatures. The tiny droplets of water in the unsealed pores of your concrete will expand as they freeze. This will literally destroy your concrete, and it will do so fairly quickly.

There are two different types of concrete sealer available.

Now that you know what concrete sealer is, it’s time to figure out what kind of concrete sealer you want. Concrete sealers fall into one of two categories – Film Forming Sealers and Penetrating Sealers. Here are the differences between the two:

1. Film Forming Sealers (or Surface Coat)

A film-forming concrete sealer forms a solid protective layer, or film, over you concrete. This film will partially enter the pores of your concrete and then adhere, creating a resilient, hard-wearing coat of sealant over the surface. 

Sometimes called a surface-coating sealer or a topical seal, a film-forming sealer is easy to maintain and reapply, but isn’t quite as durable. Some film-forming sealers will leave your concrete with a glossy look, but many brands will offer matte-finish additives, and most will also allow you to select your desired level of sheen, gloss and tint.

Epoxy and polyurethane film-forming sealers are the more reliable and durable choices. Thinner acrylic-based sealers are a more affordable option, but they will need to be re-applied more regularly. Film-forming sealers are approved for interior and exterior use.

2. Penetrating Sealers

As the name suggests, penetrating sealers do a much better job of getting right into the concrete. They penetrate all the way into the pores of the concrete, forming a long-lasting and durable protective layer all the way through your surface. It’s great for both interior 

Penetrating sealers need to be reapplied much less frequently than a film-forming sealer and have better resistance against contaminants like grime, salt, oil and water. If you’re expecting your concrete to get very dirty or endure some heavy-duty conditions (think your garage) then you should invest in this type of sealer. It’s usually the better choice for commercial uses too.

One more thing – these penetrating sealers have a more natural-looking finish than film-forming sealers, which will be desirable for many people. However, you may not get quite as many choices when it comes to colour enhancement or tinting.

What are the safety considerations?

Sealer isn’t the most dangerous thing in the world, but it still requires a fair bit of caution. Getting it in your skin or eyes can do some real damage, so make sure to always wear gloves, eye protection, long sleeves and trousers when you’re applying this stuff.

Wear a mask while applying sealer if you can, and try to avoid breathing in any fumes at all, especially if you’re using a petrochemical-based sealer. If you’re applying it inside then take extra care to ensure there is ample ventilation, as these fumes can be toxic and may cause respiratory stress or damage.

When is the right time to apply sealer to my concrete?

You can put concrete sealer on at almost any time, but not if the concrete is fresh. You should let freshly laid concrete rest and cure for around a month before you put sealant on it.

In terms of when you need to re-seal, it depends on the severity of the conditions and the quality of the sealer. A lot of sealer companies will swear that you need to reapply every 1-3 years (no surprises there) and that’s roughly the lifespan of acrylic sealers. However,  the truth is that a high-quality concrete sealer can last for roughly a decade.

You can tell that it’s time for a re-seal when stains, grime and scratches are visible on your sealant layer. When water appears to soak into the concrete instead of forming droplets on the surface, that’s another sign that your sealant is losing it’s waterproof qualities.

 Finally, if you’re doing up some existing concrete, be sure to wash it first. The last thing you want is to trap pollutants and moisture beneath your layer of fresh new sealant.

Thanks for reading our guide to concrete sealers. If you’re a DIY user who is looking to seal some concrete, this information should give you a much better understanding of what you’re doing, and what kind of sealant you should use for the job. 

Multifors is an online hardware store that’s focused on convenience and quality. We stock a curated range of high-quality sealers, from trusted brands like Stain Proof, Environex, Chemforce and Envirosheild. Shop our range today with next-day delivery across Metro Melbourne for only $19.95.