Deck Sealing Services

1400 N Winnemac Sealing Post and Apron - CopyDECK SEALING SERVICES

Within the two basic categories of oil-based and water-based sealants, there are several types, each with different characteristics.  Depending upon the type of wood, the aesthetic preferences of the client and the project characteristics, one type will be more appropriate than another.  Different sealants also have different lifespans, always an important factor in the customer’s selections.  A description of the way our crews apply the product is included here, and advice as to how to determine when to reseal your decks.


There are innumerable deck sealants available, most of which do an effective job of sealing and protecting wooden surfaces, and they fall into two major categories: oil-based … and water-based sealants, usually acrylics. As a general rule, oil-based sealants can last 1-2 years longer than water-based sealants (acrylics), but acrylics are more environmentally friendly and require a much easier clean up.

Oil-based sealants soak into the surface and slowly wear away, for a rich, natural look, requiring no sealant removal between applications. The thinner the oil particles (low viscosity), the more deeply they can penetrate, so lowest viscosity sealants that penetrate deeper and last longer are always more expensive.

Acrylic sealants have a uniformly painted look, masking flaws very well and allowing creative color options, but are high-maintenance. They form a layer on top of the surface instead of soaking in, which often wears unevenly and requires occasional touch-ups, often monthly after the first year. Acrylic sealant remaining from previous applications must be removed prior to resealing the surfaces.

These GENERAL rules were augmented in 2009, when new EPA standards forced sealant formulas to change drastically to capture the benefits of an oil-base, while still conforming to these standards.  The EPA ordered that, as of July 1st, 2009, lower VOC (Volatile Organic Compound) limits will be in effect within the state of Illinois. Under these regulations, oil-based products (which have naturally higher VOC levels than acrylics) can no longer be applied or sold in Illinois unless reformulated to meet these new standards.

Manufacturers of oil-based products are continually reformulating their products, in order to conform to the new standards. Some have developed alternative formulas containing alkyds, an EPA-friendly combination of oil and acrylic, to substitute for the oil-based products. Others are experimenting with nanotechnology and modified acrylic formulas that have oil-base-like characteristics, yet are, essentially, acrylic.

Because new and better products are being introduced to the market every season, it is important, tho growing increasingly difficult, to research all new offerings. The sealant that was the best to use on your deck last time it was sealed, may very well not be the best to use next time.

Within both oil and water-based categories, there are essentially four sealant types:
• CLEAR sealants that allow natural greying to occur
• TONERS that are slightly tinted, highlight the grain for a natural appearance
• SEMI-TRANSPARENT sealants that partially cover the grain with color, and
• SOLID (opaque) sealants that cover the grain completely.

Expensive woods like cedar, Western redwood, or exotic varieties like Ipé, or the Brazilian hardwoods, are usually covered in a sealant that allows the natural beauty of the wood to show, while chemically treated wood and older, damaged wood is typically covered with a product that will effectively mask the stains. Most brands offer a broad range of colors from which to choose.

The heavier the tint, the more pigment it has, so the longer the sealant will last.

Clear sealants, whether oil-based or water-based, last no more than 1 year on horizontal surfaces and 2-3 years on vertical surfaces, depending upon exposure. This is an excellent choice for owners of cedar or redwood decks, allowing the full-bodied natural color of the wood to show through, while adding a richly burnished, translucent tone.

Owners of pressure-treated wood decks (like most multi-unit porches), want to minimize maintenance while enhancing appearance. They use a tinted toner, like Olympic’s Maximum line of sealants, that need not be stripped when resealed.  The toners are warrantied to last between 3-5 years, so flat decking is powerwashed and resealed every three -four years, and every five-six years the vertical surfaces are done.

Semi-transparent sealants can last up to 5 years, and solid (opaque) sealants last even longer, but sealant removal or sanding is required between applications, adding cost in the long term.

The cleaned surfaces of the wood must be COMPLETELY DRY, usually 24-48 hours after powerwashing or last rainfall.  Our crews take all possible care to protect the property and its surrounding area prior to sealing the surfaces.  All areas to be protected are tarped extensively and all plants are lightly watered with a garden hose before they are tarped.


While spraying is the easiest way to apply sealant, Chicago winds make it virtually impossible to spray sealant without getting overspray onto windows and walls. These airborne particles reach areas even blocks away and can destroy the finish on nearby parked cars, coat children’s toys and expensive grills in nearby yards or ruin the paint on siding and garages, costing thousands of dollars. The time saved by using a sprayer is not worth the risk of costly repairs or lawsuits from disgruntled neighbors.

While the sealant’s color will fade naturally in the months following your last application, this is a natural process and does not mean that the surface is no longer protected. If you fill a glass with water and spill it onto your deck, the water should form tiny beads on the surface if your sealant is still working.  If your deck is grey, and water no longer beads up on the surface … it is time to call POW! POW! Powerwash’nSeal ® to clean and reseal all your wooden surfaces!