Concrete Sealing in Corvallis, OR

The problem with wet concrete

Concrete is porous. On a patio or walkway that stays damp from October through spring, water soaks in and carries dirt, tannins from fallen leaves and spores with it. Moss, algae and lichen take hold in the pores and turn the surface green or black. In shady yards under firs and maples, the surface can become slick enough to be a hazard. When cold snaps arrive, the water inside the concrete can freeze and expand, causing surface flaking over time. Sealing reduces how much water the concrete absorbs, which slows all of that down.

Cleaning comes first

A sealer locks in whatever is on the surface, so we never seal dirty concrete. We start by treating moss and algae, then clean with a rotary surface cleaner and hot water where needed. Oil and rust stains get specific treatments. Old, failing sealers are stripped so the new product can penetrate. Then the concrete must dry, which is the trickiest part of the schedule here. We watch the forecast closely and seal during dry stretches, typically in late spring, summer and early fall.

Choosing a sealer

• Penetrating silane or siloxane: soaks in and repels water without changing the look or making the surface slippery. Our usual choice for walkways, steps and driveways.
• Acrylic film-forming sealer: adds a wet look and deepens color on stamped or colored concrete. It needs reapplying more often and can be slick unless grit is added.
• Densifier: hardens the surface of interior or covered slabs and reduces dust.
• Polyurethane or polyaspartic clear coat: a tougher film for covered patios and garages where more protection is needed.

For most outdoor concrete in this climate, a breathable penetrating sealer is the safest bet. It lets moisture vapor escape from the slab instead of trapping it under a film that can turn white or peel.

Areas we seal

We seal patios, walkways, front steps, pool decks, driveways, garage floors, retaining walls and concrete around hot tubs. For businesses, we seal sidewalks, entries, loading areas and parking structures. We can also seal brick and paver patios with products designed for those materials.

How long it lasts

Penetrating sealers typically last several years on walkways and patios, depending on sun exposure and traffic. Film-forming acrylics often need a fresh coat every couple of years. A simple test tells you when it is time: if water stops beading and starts darkening the surface quickly, the sealer has worn. We are happy to set up a reminder schedule so your concrete stays protected.

Keeping it clean

Sweeping off leaves and needles before they sit through a rainy week does more than any product. A gentle rinse each spring removes the film that feeds algae. Avoid harsh acids and high-pressure wands held close to the surface, which can damage concrete. If your driveway also needs attention, see our driveway coating page, and for interior slabs, ask about garage floor coatings.

Getting started

Tell us what you want to seal, how large it is and whether it has moss, stains or a previous sealer. We will visit, look at the surface, and give you a written estimate with the product we recommend and the timing that fits the weather.

Safety on shaded walks

Front steps and walkways that sit in shade under evergreens are the surfaces most likely to grow a slick film of algae. Beyond sealing, we can add a fine anti-slip additive to film-forming sealers on steps and ramps, and we can recommend simple habits, such as trimming low branches to let in more light and air. A cleaner, drier, sealed surface is far less slippery for family members, guests and delivery drivers, especially in the dark, wet months. When we finish, we leave you with a short checklist for spring and fall cleaning so the protection lasts as long as possible between visits.