The tiny pores of a concrete slab and foundation can absorb water if not treated with a waterproofing
Although sealers will not keep pressure-driven water from penetrating the concrete, any water that is absorbed can evaporate since sealer materials are permeable to water vapor.
Concrete should be sealed to protect from mold and mildew.
When this moisture doesn't dry and the surface is left wet for an extended period of time, mildew begins to form and mold begins to grow. You'll know you have mold growing on your concrete by the greenish color that appears.
Concrete can also be protected against the water with acrylic, polyurethane, polyurea-based materials that provide waterproofing in areas that are exposed to direct water and sunlight such as roofs and terraces. All of these practices are applied directly to concrete surfaces.
If you apply the sealer and it rains within 24 hours, the unreacted material below the surface can be diluted by the rain. Unfortunately, there aren't many immediate signs that will indicate whether or not the sealer was affected.
Weather: Concrete sealers need a dry surface for proper application, and so you should avoid sealing if rain is expected within 24 hours of application. Additionally, try to choose a day with little or no wind, as strong winds can introduce debris and dust onto the freshly sealed surface.
Coating problems can include surface bubbles (aka solvent pop), peeling/flaking, white spots (aka blushing), fading (loss of shine). Surface bubbles (aka solvent pop) can occur during the coating application process when solvent is evaporating too quickly from a sealer.
Our top pick, BEHR PREMIUM Wet Look Concrete Sealer, can be used on multiple surfaces indoors and outdoors. It is also easy to clean and apply. Rust-Oleum Moisture Stop Fortifying Sealer is an excellent budget-friendly option that can be applied quickly and creates a waterproof barrier that protects your concrete.
Liquid Waterproofing Membrane
By using a liquid waterproof membrane, you can cover a large area as compared to other methods. When using this method, ensure the layer is thick as the thinner membrane can easily break. The technique provides optimized performance and longevity while yielding maximum results.
Sealers should be applied after pouring to help prevent water from coming into contact with the slab and provide protection against staining. The sheeting or membranes should be placed between the soil and the slab before the concrete is poured so that water does not come into contact with the surface of the slab.
Acrylic Concrete Sealers: Acrylic sealers last 1-3 years before they need to be re-coated. Epoxy Coatings: Epoxy coatings last 5-10 years before they need to be re-coated.
Sealer that is applied too heavily or too often will create an impermeable barrier and trap that water vapor beneath it. If enough pressure is created by trapped water vapor, the sealer can delaminate from the concrete surface, and might even take some of the concrete paste with it!
Sealing your concrete isn't really a labor-intensive, nor costly, job. By sealing your concrete every 2-5 years, as recommended by experts, you should keep your floor in good shape, preventing cracks, pitting, and additional damage.
Smooth Concrete Sealer Basics
Penetrating Sealers soak into porous concrete and masonry and create a permanent chemical reaction. They offer a flat appearance and protection that will only wear away if the substrate itself wears away below the level of sealer penetration.
Concrete is by design a porous material and water can pass through it by hydrostatic pressure, water vapor gradient or capillary action. Water can also enter at cracks, structural defects or at improperly designed or installed joints.
No, water isn't going to soak up like a sponge, but concrete does allow water to seep through when there is enough. Concrete also cracks, and those cracks will be the first routes of seeping water as it leaks through the slab.
Left unprotected, stains, foot traffic, and UV rays can cause the concrete to fade and discolor. A simple way to protect the slab and enhance its appearance is to seal it. Sealing repels moisture – If irrigation is near the slab, spalling (flaking concrete) can occur. It also prevents mold and mildew growth.
If it isn't already obvious, having a concrete sealer greatly improves your driveway's ability to stand up to the elements, thereby allowing it to last longer. With proper application of the sealer and regular resealing, a concrete driveway can be expected to last for many years without forming any cracks.
Normal concrete is not fully waterproof. The terms can get confusing, but waterproof concrete is both damp-proof and watertight – this means that not only is soil moisture prevented from getting through to the concrete, but liquid water cannot penetrate it either.
Acrylic topical coatings have the shortest lifespan, needing re-applied every 1-3 years. Epoxy and urethane systems last between 5-10 years, closer to 5 if the surface experiences heavy traffic.
When the sealer is applied too heavily, the air displaced through the surface can't escape, and it forms a bubble in the sealer surface. Concrete sealers are best applied in two thin coats.
During the late afternoon, any moisture present from condensation or morning dew will have evaporated off during the day. Also, both the surface temperature and air temperature are declining, creating a more favorable environment for concrete sealers to properly bond to the substrate and cure.
If you are resealing your concrete and pavers, and there is still a visible film on the surface, you will require 1-2 coats. We always suggest starting off with one coat and waiting 24 hours to see if you need a second coat. If this is your first time sealing, typically 2-3 coats will be required depending on porosity.