Tuesday, October 14, 2008

Exterior Wood Care

Semi-transparent and Translucent Coatings

Exterior wood surfaces are exposed to a variety of harsh elements. Ultraviolet rays, rain, sleet and snow all contribute to damaging those surfaces. You have several choices when evaluating exterior wood coatings for siding and trim. Many choices will offer trade-offs with respect to translucency, frequency of maintenance, ease or difficulty of application, preparation required, and so forth. Some species will have specific coating requirements, especially dense hardwoods, and not all coatings are appropriate for all situations. The coatings listed below have all performed extremely well for us and our clients over the years, and each has it's own distinct features. Our wood care specialists can help with expert advice and high quality products direct from the following wood coatings manufacturers:

Structures Wood Care offers a Water-borne Satin Finish for Log Homes, Wood Siding, Timbers, Fencing and Garden Furniture, Entry Doors and Garage Doors.

One TIME is a Natural Finish for Log Homes, Decks, Wood Siding, Docks, Timbers, Fencing, Shakes, and Garden Furniture.

Sikkens carries Oil-Based Satin Finish for Log Homes, Wood Siding, Timbers, Garden Furniture, Entry Doors, Garage Doors

Waterlox is used for Hardwood Flooring & Decking, Exotic Hardwood, Entry Doors and Garage Doors, Garden Furniture. Use when a clear finish is desired.

The overwhelming principle we want to impart is that wood loves water. Unsealed wood will absorb moisture any chance it gets. Unsealed saw cuts, and uncoated concealed wood leads to a legacy of costly maintenance that can be easily avoided if we follow 3 principles during construction:

1. All end grain (saw cuts) must be sealed with a water-proofer, wood sealer, or glue if we want to avoid unneeded moisture intrusion and deterioration. The cost of backside and end-grain sealing during construction is offset fivefold or more over the expected life of the structure.

2. We must use a coating that is flexible and breathable to insure that trapped moisture does not cause coating failure (See
Spar Varnish).

3. Seek to
choose a coating appropriate for the UV sunlight exposure given the particular species of wood, while considering client expectations and maintenance capabilities.

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Monday, October 13, 2008

Stains and Finishes for Exterior Wood

Exterior wood care requires first the knowledge that a maintenance program is required regardless of your coating choice. Maintenance does not consist of simply reapplying coating to the house every 1-3 years. Many clients face conflicting information, and unmet expectations with respect to the various wood care choices. Basically, the more translucent or “ natural” the coating is, the more frequent the maintenance cycle when compared to more opaque or heavily pigmented products. Wood coatings manufacturers rely on a variety of ingredients to create their products. Many times, products sacrifice one benefit at the expense of another. A product that has all the elements of a premium product (appearance, UV resistance, moisture resistance, ease of application, and simplicity of use) will appear costly at first when evaluated only on a per gallon cost, or on the basis of the initial cost of the complete coating system.

Regarding the common problem with blackening and mildew, it is usually a combination problem. Many heavily advertised and available wood care products rely heavily on a linseed oil base, with inexpensive pigments and waxes, as do most of the products available at the “Big Box Stores”. While the linseed gives short term richening and waterproofing of the wood, that protection is short lived. Once the coating fails to repel moisture, a couple of things occur. First, the wood begins to hold moisture on the surface, and combined with the linseed base, you have a surface that is highly conducive to mildew growth. Further moisture intruding and exiting can “bleed” extractive from darker woods causing varying degrees of staining. This moisture transfer, combined with the breakdown of inexpensive pigments leads to UV degradation, that causes the coating to release from the surface, and also causes further organic growth on the surface of the wood in a continually accelerating cycle of deterioration.

The products featured at LogCare.net and PaintSource.net combine all the elements proven for premium protection and enduring beauty for various wood care projects. Coatings choices represent our research, testing, and continual evaluation of available wood care products.

Some choices are “rustic” or “natural” looking, while others are more “finished” or “varnished” looking. Some choices are oil-based, some are water-based, and one is neither water or oil. Each of these choices offers distinct advantages, performance capabilities, application ease or difficulty, and maintenance frequency. Your coating
choice should be made after evaluating your expectations, existing surface conditions, and desired appearance. We will be happy to assist you in making that choice.

One great coating choice if you desire simple natural looking wood protection with extended maintenance cycles is OneTIME Wood Protector. One Time is not shiny, is easy to apply , and gives you good color retention for 3-4 years on SW exposure (much longer on NE), and 7 years protection against organic growth on the wood surface. The One TIME has various advantages with some trade offs when compared to the Sikkens or Structures.

One TIME can be applied only to bare new wood, or to stripped wood. Any previously applied product should be chemically (or cob blast) stripped prior to the application of One TIME. One TIME represents probably the longest lasting, least costly option for exterior wood care.

Still, some clients prefer the look of a more finished surface with a satin sheen. For those clients, the following represent our coatings of choice.

Sikkens Cetol (see-through) refers to their “translucent line of coatings and stains, and there are three distinct products for logs and wood siding within the Cetol line. Cetol 1/23 , and Cetol Log & Siding. These choices offer various performance, application, appearance (degree of sheen),and maintenance variables that should be evaluated based on your specific project requirements. Sikkens products have exhibited excellent performance for our clients. Most surfaces require sanding for the use of Sikkens Wood Coatings.

If you desire the finished satin look of the Sikkens Cetol 1/23, or Log & Siding, but want a waterborne formulation, we would certainly consider Structures Nature One for mildew prone environments. See a recent Structures project here. Nature One is our product of choice when a translucent satin finish is desired by our client. Many clients convert to the waterborne technology of Nature One for maintenance on an existing Oil based or Alkyd Finish.

Again, all three choices offer a variety of performance, appearance, and maintenance characteristics. All represent premium choices that outperform most products available. All use expensive Transoxide pigments giving the most natural looking, longest lasting UV protection possible in each coating category.

I hope this information is helpful.

Doug Wilson
About PaintSource

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