How to seal exterior concrete surfaces

Between Concrete and a Hard Place —

The Choice of Whether or not to Reseal an Exterior Concrete Surface.

The phone rings. The job sounds simple: reseal an existing exterior concrete surface. It could mean repeat revenue down the road. But it’s not that easy.

Periodically cleaning and resealing exterior concrete isn’t always the best long-term solution. Applying layer upon layer of seal will eventually create problems and alter the look of the original concrete. Plus, there may be existing problems with the concrete itself that no amount of seal can fix.

Repeat after me!

We say it all the time. No two jobs are exactly the same, and no two solutions are exactly the same. So don’t agree to reseal an exterior concrete floor site unseen. Inspect it first hand and determine whether or not the concrete really needs to be resealed in the first place.

Reasons not to reseal:

1. The main reason not to reseal exterior concrete is that it won’t accomplish what most clients are hoping for — a new looking surface. No amount of seal will make a concrete floor look new again.

2. Resealing won’t fix problems or imperfections in the floor, and the client needs to know that. Set their expectations upfront that resealing their exterior concrete won’t fix damage due to ware, impact, or anything that went wrong during installation. It won’t fix flaking, chipping, or delamination. The concrete will certainly appear nicer for a while, but whatever was wrong will still be wrong.


A risky job is a risk to your reputation.
If you anticipate serious challenges or feel that what the client wants isn’t possible, if you can afford to, don’t take the job. Pleasing a client at the expense of what’s right is a risk to your reputation. If the floor doesn’t meet their satisfaction, you’ll hear about it, and so will the internet. One bad review it all it takes to lose business. Only take a resealing job if you’re confident it will come out well.

Consider other possible solutions.

Before deciding to reseal an exterior concrete surface, consider alternative solutions. If what the client really wants is a shiny new surface, a sealer rejuvenator, penetrating sealer, or statin might be a suitable way to breathe life into the existing sealer. There simply may be a more cost-effective to restore a glossy look.

Solvent-based vs. water-based acrylic sealers:
Once you’re sure that you’re going to reseal, you have to decide whether to use a solvent-based or water-based sealer. The choice comes down to which will adhere better, and form a stronger seal.

If you have a solution that works for you, stick with it. But generally, solvent-based sealers give you a big advantage in both important areas, adhesion and strength. Quickly after being applied, they liquefy the existing sealer coat, enabling the new seal to strongly adhere. For the new seal coat to wet out the existing sealer usually takes about a minute to a minute and a half, and often requires you to roll the reseal into the existing one. So be patient and go slow.

Factors that can result in a failed application:
• Poor adhesion
• Too many layers of seal already
• Dirt on the surface

If you have no choice but to reseal and are unsure about the condition of the floor, strip the existing seal and eliminate your risk. It’s not an easy step, but it’s the safest one you can take. Please feel free to call (866) 835 6595 for more information.

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