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WOOD Industrial Strength Sealant

SEAL-IT Wood Sealant creates a permanent, effective seal against moisture, acids, time and weather, while hardening, increasing density and strengthening new or existing wood.

SEAL-IT Wood Sealant does not stain* or colorize wood and allows for painting and/or staining wood surfaces. Paint and stains last up to 300% longer.

SEAL-IT Wood Sealant seals old wood and will also re-seal aged pressure-treated wood.


Do NOT use Seal-It Wood Sealant in a manner that allows contact with glass, glazed surfaces or aluminum.
SEAL-IT Wood Sealant may also be used on pressure treated wood if the pressure treated wood has been exposed to the outdoor environment for more than 6 months. (Also see Seal-It CCA Sealant)
SEAL-IT Wood Sealant is not recommended for veneers or man-made wood products.

* See Article on Tannins and Wood

  • Before Wood Sealant

  • After Wood Sealant

  • Dilution

    none, use as supplied

  • Freeze Temperature

    0 °C / 32 °F

  • Freeze Harm

    none, thaw and agitate completely

  • Boiling Point

    110°C / 230 °F

  • Shelf Life

    Several Years

  • Coverage

    150 - 200 sq.ft./gal (approx.)

  • Solvent For Clean-up


  • Color Of Solution


  • Color When Applied

    minimal darkening

  • Odor


  • Toxicity


  • Flammability


  • Fumes During Treatment


  • Organic Properties


  • Environmental Hazards


  • Polymerized Content


  • Aiding the Paint Trade

    Time-Tested Performance

    Before painting (i.e.: staining, varnishing, etc.) wood, SEAL-IT Wood Sealant is a necessity. We have all seen paint on wood that is flaked, blistered, cracked, or crumbled. Why do paints blister and crack on wood surfaces? It is due to a problem called saponification. When soap is manufactured, the basic ingredients are a form of alkali and oil. The combination of alkali in the wood and the oil in the stain causes saponification, which in this case, is more commonly identified as flaking, blistering, and peeling of paint from the surface. This occurs when using oil-based paints which are rapidly disappearing from the market.

    This beekeepers log home is coated with SEAL-IT Wood Sealant. Notice how the beauty of the wood grain is maintained.

    Although much better than oil-based paint, the vinyl, rubber, or latex-based paints which are in widespread use today, also have the tendency to peel and crack off the surface. The primary reason for this is that the alkali is still fighting the paints. In the event that these surface coatings are used as a sealer or waterproofing agent, they must be applied and periodically re-applied so that eventually the surface contains many layers of coatings. This provides only temporary relief, with high repeated maintenance costs, while leaving the finished product less than pleasing to the eye.

    The application of SEAL-IT Wood Sealant to wood surfaces will give an alkali free and moisture free (i.e. reaction-free) surface for better bonding of paint. When applied in accordance with the manufacturers' directions, the paint life on the structure can be increased up to 300%, providing a longer "fresh paint" appearance and reducing maintenance costs.

    Any treated or surface coatings must first be removed so that SEAL-IT Wood Sealant can penetrate.

    On occasion, foreign matter such as grease and oil will float to the surface after applying SEAL-IT Wood Sealant. This foreign matter should be rinsed away with water (in excessive areas, several rinsings may be needed), prior to painting.

  • Barns and Agriculture

    Time-Tested Performance

    Preserve & Protect

    Protection & preservation of your valuable investments makes economical sense. Repairs and replacements due to corrosion on metals, concrete deterioration and/or rotting wood seem to be a commonplace fact of life.

    High-quality, industrial-strength sealers & coatings matched with proven application techniques helps protect your valued investments - and livelihood.

    For your concrete...

    SEAL-IT Concrete Sealant gives a sealed non-slip surface which keeps urine from penetrating. As a result it reduces the breeding environment for harmful bacteria and odors. SEAL-IT Concrete Sealant stops the manure from destroying the concrete and makes concrete easier to clean. Another important feature is when applied to green concrete it reduces the problems of cracked hoofs for the sows until concrete is totally cured.

    For you metal and concrete...

    429 is a low-maintenance surface sealer for paintable surfaces. It is particularly formulated for a high corrosion, high moisture high traffic environment.

    • Comes in gray, clear & silver
    • Has a 24 hour curing time
    • Will cure at temperatures as low as 20 F or -7 C
    • Is a single component polyurethane sealer

    For wood...

    • Is a non-toxic penetrant sealer
    • Retards dampness, molding, fungus, warping, and rotting
    • Waterproofs and hardens the wood
    • Extends the life of paint or stain
    • Leaves a natural finish

    *Extends the life of concrete in high corrosion and high moisture areas by keeping the concrete from breaking down
    *Provides a non-slip surface
    *Allows for low maintenance cleaning
    *Shortens curing time of concrete
    *Eliminate concrete dusting
    *Prepares concrete for adhesives

  • Don't Give-up on Cedar

    Are you a fan of the "classic" or "rustic" look of cedar as a roof or siding treatment? Seal-It would like to pass on information that we feel is important to you. "Bad news - good news" scenario; bad news, cedar is not what it once was; good news, Seal-It can help.

    “Cedar Shake Roofs do not last as long as they used to"1

    The younger or second growth raw cedar blocks that are normally used for producing new Cedar Shakes produce two specific problems. First, it is harder to produce good hand-split cedar shakes from wood with the wider grain of young cedar blocks. Good Hand-Split shakes have had the longest life expectancy, but without sufficient supply, the product of choice is now being produced is the "Tapersawn Shake". A fully sawn 5/8" thick shake, it takes the lowest pick of the raw wood pile to produce this machine made shake, and it is now the "normal" shake provided by the industry in South West B.C.

    Tapersawn shakes have shown to have a shorter life expectancy as a roofing material. Where some may survive to 14 or 18 years of age before requiring re-roofing, many roofs with Tapersawns have suffered premature failure in as little as 8 to 10 years. This is a very short useful life for a roof as expensive as a cedar shake roof.

    The second problem, related to the newer growth cedar being produced into shakes and Tapersawn shakes, is the lateral strength of the wood as well as the rot resistance of the wood is diminished.  Younger Cedar does not contain as much natural oils and density of wood as the old growth product. Tapersawn shakes can often be seen curling up, cracking diagonally and checking, as well as weeping water through the cedar itself.”

    “Cedar Roofs: The Pros and Cons2

    • Quality matters on cedar shingles. The heartwood of old growth western red cedar is rated as extremely durable because of its extractives. There is consensus that second growth timber is not as durable as the old-growth timber.
    • Wood Shingles absorb moisture because their lower edge is exposed end grain. This end grain works like a straw to wick in moisture. The moisture results in swelling and shrinking of the wood that can eventually result in cracks. Decay occurs when untreated wood remains wet for long periods.”

    Many articles can be found that discuss how cedar and other wood species do not have the same properties they once had. These lost properties were high on the list that made these species desirable. Predominately cedar is purchased for “outdoor” projects, and to require minimal care for many years. There seems to be evidence that this is not what we are getting anymore.

    You can still use cedar for its “rustic” and “classic” look. By adding Seal-It Wood Sealant, you can have the longevity of your roofing, siding and outdoor structures. Just ask Mr. Gary Puckey. Gary has been in the roofing trade for over 38 years in south western British Columbia, Canada. He has seen the change in the performance of cedar as a roofing material. He has seen the premature failure.

    Mr. Puckey has also given new growth cedar the longevity of old growth cedar with the use of Seal-It Maintenance Cleaner and Seal-It Wood Sealant.

    “I’ve seen 40 year (old cedar roofing) that is still in good shape; I’ve seen “second growth” (cedar) that needs to be torn off and replaced at anywhere from 12 to 15 years; depending on the pitch.” says Gary. Gary recommends treating “second growth’ cedar with Seal-It before it’s too late. “Anything over 12 years should be torn off”, “up to 10 year old (cedar) can be cleaned with Maintenance Cleaner and treated with Wood Sealant and the roof will last another 25 years.” Mr. Puckey, the owner of, says “I can save (a home owner) about $8000.00.”  “A 20 square roof will cost about $12,000.00 to replace, whereas I can replace ridge cap, clean and seal (existing second growth cedar) for about $4000.00.”


  • Helping Beekeeper

    Time-Tested Performance

    SEAL-IT has been talking to numerous Beekeepers and they've noticed they all have one thing in common, damaged and rotting supers or bottom boards and the deterioration of extraction room floors. Beekeepers are asking the question "what can preserve and protect our livelihood?" Well, SEAL-IT has the answer, a line of products that not only saves Beekeepers money, but also gives them peace of mind.

    Seal-It Wood Sealant for your Wood:

    • For supers, pallets, frames, lids, feeders, etc.
    • Non-toxic penetrant sealer.
    • Approved by Food production and Inspection branch -Agriculture Canada
    • Approved by Food Safety and Inspection Service - United States Department of Agriculture

    Protect your wood from moist and damp environments and all the destruction and health hazards that can result. A major part of your moisture control program. Retards dampness, shrinkage, and warping. Waterproofs and hardens the wood. Leaves a natural finish.

  • Log Homes and Builders

    Time-Tested Performance

    Log Home:

    Here is one log home treated with SEAL-IT Wood Sealant. This log home has been protected by SEAL- IT Wood Sealant since 1989 (photo taken in 1996).

    For Concrete:

    • Aids in curing concrete. (See article on concrete curing)
    • Eliminates concrete dusting (see article on concrete dusting)
    • Leaves the natural surface texture
    • Prepares concrete for adhesives, paints, and mastics. (See article on paint trade)
    • Keeps sidewalks and driveways from pitting and rotting
    • Allows for low maintenance cleaning

    For Wood:

    • Retards dampness, shrinkage and warping
    • protect your wood from moist and damp environments
    • and the destruction and health hazards that can result
    • a major part of your moisture control program
    • Extends the life of paint, stain and varnishes
    • Requires low maintenance upkeep
    • Waterproofs and hardens the wood
    • Is a non-toxic penetrant sealer
    • Makes paint, varnishes, stains, urethanes last 300% longer with less maintenance

    For more info how, refer to paint trade.

  • Mold, Mildew, Fungus, Rot and Your Environment

    Time-Tested Performance

    There are plenty of articles and web sites that discuss the environment required for the success of mold to live, grow and multiply. According to research, two requirements that are accepted as fact are moisture and food. Also, what we generally call wood rot is caused by the natural action of fungi converting wood to a source of food. Oxygen, moisture and a 40°F to 100°F temperature is all that fungi need to colonize wood. Wood rot and mold can be prevented by eliminating any one of these factors. Seal-It’s solution is to control the moisture.

    There are naturally occurring woods such as Western red cedar and redwood that are toxic to fungi. The source of these woods is too small or too costly to meet today’s requirement for rot resistant lumber. Wood species that are not naturally rot resistant are treated with pesticides (CCA) to try to imitate nature. The world is becoming less tolerant of using pesticides, and many countries are either banning or restricting the use of Chromated Copper Arsenate (CCA) as a means of wood preservation. The wood preservation industry has started to utilize a new chemical formula ACQ (Alkaline Copper Quaternary) as a pesticide which is reported to be corrosive to metal fasteners and be more costly than CCA.

    Seal-It believes the traditional wood preservation industry has missed the obvious. The focus appears to be on killing the organism after it has colonized. However, what needs to be addressed is the environment that allows the organism to grow and flourish.

    Make Seal-It Wood Sealant an important part of your moisture control program.

  • Tannins and Wood

    Time-Tested Performance

    Many wood species contain naturally occurring, water soluble chemicals that tend to migrate to the surface with exposure to extracting agents. During the application of Seal-It Wood Sealant to previously untreated wood, coffee or tea-colored fluid may appear on the wood surface or flow down a wooden wall. When tannin extractives that are dissolved by the Wood Sealant, reach the surface they may remain as dark, coffee-brown stains after the sealant “cures”. This brown-black bleeding is unsightly, but not damaging to the wood, or sealant.

    Much of the tannins can be easily removed, while in the liquid state, by flushing with water; follow this flushing by re-application of Seal-It Wood Sealant. Tannin “bleed” does not occur on wood that has been treated with Seal-It Wood Sealant.

    Should there be a situation where the tannins reach the surface of the wood but do not get flushed away before drying, you may need to use Seal-It Maintenance Cleaner and a stiff bristle brush or broom to remove the stain.

  • Added weight of Wood Sealant

    November 2005
    Saskatoon, Canada

    Seal-It International Inc. was recently asked a question that we could not answer. No one at Seal-It could remember a customer, or distributor, asking this question before. When a Colorado distributor of Seal-It products was asked to help reduce maintenance costs for a wooden treaded, pedestrian suspension bridge; the question of added weight had to be answered. Seal-It contracted the services of Enviro-Test Laboratories, a division of CHEMSPEC ANALYTICAL LIMITED, to determine the weight added when Seal-It Wood Sealant is applied.   

    Two different sized pieces of “raw” wood (non pressure treated), cut from the same dimensional piece of fir lumber, were weighed. The smaller piece labeled SIW 1 weighed 53.1165 grams; the larger, SIW 2 weighed 699.7 grams before Wood Sealant was applied.   

    Seal-It Wood Sealant was applied to these pieces of wood following Seal-its instructions. The samples were allowed to cure and dry for two days, after which they were weighed again by Enviro-Test Laboratories.   

    Wood sample SIW 1 now weighed 53.5502 grams, an increase of only 0.8165%. Sample SIW 2 now weighed 703.7 grams, an increase of 0.5717%. That works out to about 1.5 lbs per ton of wood treated.   

    Seal-It, its customers and distributors feel this is a small “burden to bare” to get the added “rot” and wear resistance that Seal-It Wood Sealant will add to your wood structures and projects.

    This document is also available in PDF format

    Download Cover Page
    Download Data Sheet

  • Flame Spread and Wood Sealant
  • Prevent Rot

    At Seal-It, we knew our wood sealant prevented rot. We were told the wood sealant would prevent rot, we believed what we were told. Our customers told us it prevented rot, and of course, we have seen for ourselves, Seal-It Wood Sealant prevents wood rot.

    But, unlike Seal-It Concrete Sealant, our Wood Sealant had fewer reported laboratory tests that confirmed its capabilities.

    We also knew, and believed, that the best place to invest profits was back into the business that generated the profit. In the past this belief led to investment in advertising, both print and internet. With less than profitable results, actually less than breakeven results, we were disillusioned about advertising.

    Although, still believing in the principle of re-investment in your own business, we decided to enhance the value of one of our hottest selling products, Seal-It Wood Sealant. Could it be proven scientifically that our wood sealant prevented rot?

    Now to find a business that could prove Seal-It Wood Sealant would prevent wood rot, scientifically! This seemed to prove more difficult than we thought it should have, searching the internet provided sparse results. But the search did provide results. Lakehead University, Thunder Bay, Ontario, Canada could do what we were looking for. This made sense, Thunder Bay, Ontario, in the heart of lumber country!

    We talked to Dr. Mathew Leitch, Professor of wood science. He and his associate presented Seal-It with a plan to prove Seal-It Wood Sealant’s ability to prevent wood rot.

    This, below, is the text from email received from Dr. Leitch: 

    I have talked it over with the other Prof who will work on this and we have come up with a plan. The process of testing this according to standards is to place the blocks as I mentioned into a media that has white and brown rot fungi (separate for each type of fungi). The standards recommend testing of several boards. So we see testing 10 to 20 cubes in each fungi type and a similar number for controls in order to compare the mass loss.

    So, in our words, Seal-It would provide Professor Leitch with pine wood cubes, some treated with Seal-It Wood Sealant, and some not. We took pine lumber, fresh from the lumber yard, and cut 150 cubes ¾” x ¾” x ¾”. 100 of these cubes were treated with Seal-It Wood Sealant, and 50 left untreated. The cubes were individually identified and placed in sealed containers for delivery to Lakehead University. 100 treated cubes in one container, 50 untreated cubes in another container. Each container, as clearly as possible, identified as to its contents; “Treated with Seal-It Wood Sealant”, and “Not Treated”.

    From here on, we are told the blocks of wood will be placed in controlled environment containers. One of four types of fungus placed in these containers with the wood.

    According to the internet, these fungi are responsible for wood rot.

    The lab received the wood cubes mid December 2016, and Seal-It received test results in Late July 2017 with this quote from Dr. Leitch: “Please find the results for the durability tests we did for you.”, “It appears the solution you have is pretty effective.”

    We were quite pleased with that quote coming from a person that signs his name:                     

    Dr. Mathew Leitch, HBScF Chair
    Associate Professor
    Faculty of Natural Resources Management
    Wood Science and Forest Products
    Director, Lakehead University Wood Science and Testing Facility.

    At the end of about 7 months, with wood cubes and fungus in containers that had been temperature and humidity controlled for optimum growth conditions of the fungus, the containers were opened.

    Each cube would be weighed with the expectation that rot would have removed material from the wood. Less weight means more rot activity. The results of testing are in the table below.

    “Control” designates wood cubes placed in humidity and temperature controlled containers with “no” rot fungus added. Some of the cubes had been “untreated” (UT) with Seal-It Wood Sealant, and some cubes had been “treated” (T) with Seal-It Wood Sealant.

    So why did these cubes gain weight? Dr. Leitch addresses this and explains the increase in weight probably due to the addition of nutrients for the fungus, and the fungus itself.

    Further on in the results table we see that there are both treated and untreated wood cubes exposed to each of four types of rot fungus. Three of the four fungus show from 8+% to 29.5% weight loss for wood cubes untreated with Seal-It Wood Sealant. And for wood cubes sealed with Seal-It Wood Sealant, from just under 2% loss of weight to just over 1% increase in weight.

    So, to quote Professor Leitch’s: “All in all there appears to be a significant difference in the treated over the untreated samples in this study.”

    Decomposition results (UT = untreated, T = treated) (averages based on 5 blocks)

    Treatment                             initial weight              final weight      % weight differance                                               (average) (g)             (average) (g)  

    Control (UT)                              2.3166                      2.3736              2.46% increase

    Control (T)                                 2.4556                      2.4642              0.35% increase

    Fomitopsis pinicola (UT)           2.3216                      1.8782            19.09% decrease

    Fomitopsis pinicola (T)              2.6168                      2.5662              1.93% decrease

    Fomitopsis cajanderi (UT)         2.3058                      1.6254            29.50% decrease

    Fomitopsis cajanderi (T)            2.4694                      2.4952               1.04% increase

    Gloeophyllum sepiarium (UT)   2.3978                      2.1848               8.88% decrease

    Gloeophyllum sepiarium (T)      2.4414                      2.4126               1.17% decrease

    Trichaptum abietinum (UT)       2.2906                      2.3356               1.96% increase

    Trichaptum abietinum (T)          2.4848                      2.5164               1.27% increase


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Boost confidence using salvaged wood   12/31/2010 We built a fence from salvaged wood in 2005. 1 x 6 tongue and grove pine is used as vertical parts of the fence. Seal-It Wood Sealant was applied that same summer. We made sure that the cut end of the boards got as much sealant as they would…

Danial Home heir

Still going strong!   02/06/2011 We sent Seal-It a testimonial in September 2003 describing how your wood sealant was performing since we used it in 2000. It has been 10 years since we used your sealant and now we notice that there isn't even graying wood. There are no signs of rot or any other…

Steven Beatty Carpenter and commercial fisher

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