Why Silvertjära Altan Tar Oil is Especially Suitable for Terraces in the Baltic and Scandinavian Climate
Decks in Latvia or Scandinavia face entirely different challenges than decks in Southern Europe. Here, the main "enemy" is not continuous sun exposure, but moisture combined with frost. Wet autumns, freezing periods in winter, and countless freeze-thaw cycles each season create stress that many deck oils are not designed to withstand.
In this article, we will explore what happens to a coating when the water in it freezes, and why traditional tar oil, such as Silvertjära Altan, often lasts longer in our climatic conditions than many modern deck coatings. We will also examine the limitations of this product, as no deck oil is a perfect solution for all cases.
Why is the deck the most challenging wooden surface to protect?
The facade drains water. The deck accumulates it. This difference makes horizontal wooden surfaces the most challenging surfaces to protect.
Rainwater accumulates on the deck rather than draining off. Snow can remain on it for several weeks. The horizontal surface receives direct sunlight, but daily movement gradually wears down any coating. All this time, the wood continuously absorbs and releases moisture, expanding and contracting with weather changes. A coating that works well on a facade can lose its properties surprisingly quickly on a deck because the stress is much greater.
Therefore, the most important question is not: "Which deck oil looks the best?", but rather: "Which coating can withstand moisture and frost cycles year after year?"
The main problem – freeze-thaw cycles
This is where the climate causes the most damage. Many modern deck oils and facade paints are water-based. They are easy to apply, practically odorless, and dry quickly – real advantages. However, in cold climates, the water present in the coating or gradually entering it during use becomes a problem.
When water freezes, its volume increases by about 9%. This expansion creates pressure from within the coating. Thawing, refreezing, expanding again – and after many such cycles, the coating's structure begins to break down at a microscopic level. The result is cracking, peeling, and detachment of the coating – phenomena well known to any deck owner. When cracks appear on the surface, water penetrates beneath the coating, and the wood decay process begins even faster than in untreated wood.
Why does Silvertjära work differently?
The answer is simple – it contains no water. Silvertjära Altan consists of pine tar, cold-pressed linseed oil, natural balsam turpentine, and mineral pigments. It contains no water or petroleum-based solvents.
Linseed oil penetrates deeply into the wood, while pine tar and pigments form a protective layer that reduces moisture absorption. Since the coating contains no water, it is not affected by the same freeze-thaw mechanisms that gradually damage many water-based coatings.
In addition, pine tar has natural protective properties. Phenolic compounds help inhibit mold and rot development, while resin acids naturally repel water. This material has been used for centuries to protect Scandinavian boats, docks, and buildings. It is not a romantic tale of traditions – these are physics and chemistry processes based on science.
Absorbs into Wood, Does Not Form a Film
Another significant difference is how the coating works on the surface. Many modern coatings form a film on the surface. On a deck, this film is continuously subjected to mechanical stress and wood movements. Sooner or later, it starts to crack. When this happens, water gets under the film, and the coating itself becomes a problem.
Silvertjära Altan absorbs into the wood and does not become a separate surface layer. Therefore, it does not crack or peel. Over time, the coating wears gradually. The practical benefit – restoration means cleaning the surface and applying a new coat, rather than sanding and removing the old coating.
Why is a Silver-Gray Tone a Smart Choice for a Deck?
Any wooden surface will turn gray over time. Ultraviolet radiation breaks down lignin – the natural substance that binds wood fibers. The wood surface gradually acquires a gray hue. Many coatings try to stop this process, but in the long term, it is practically impossible.
The product is specifically designed for wood that has already turned gray or has been outdoors for at least one season. Instead of the deck becoming patchy gray and uneven, Silvertjära provides a uniform and aesthetic silver-gray tone from the very beginning. The manufacturer notes another advantage – the treated surface produces fewer splinters, which is especially important if the deck is frequently walked on barefoot.
Comparison with Modern Deck Oils
| Characteristic | Modern Deck Oils | Silvertjära Altan |
|---|---|---|
| Resistance to Freeze-Thaw Cycles | May Crack if Moisture is in the Coating | Contains No Water |
| Operating Principle | Often Forms a Film | Absorbs into Wood |
| Wear | May Peel and Crack | Wears Gradually |
| Maintenance | Sanding Often Required | Cleaning and Reapplication |
| Drying Time | Fast | Approximately 1–2 Days at +18 °C |
| Odor | Slight | Distinct Tar Smell |
| Color Selection | Wide | Silver Gray |
| Application Temperature | Flexible | Above +18 °C |
| Required Number of Coats | Often Several | Usually One |
Things to Consider
- Slower drying: Silvertjära penetrates deeply into the wood, requiring temperatures above +18 °C and one to two days for drying.
- Distinct tar smell: The product contains no synthetic solvents, so the natural pine tar smell is noticeable. Over time, it gradually fades.
- Only silver-gray tone: The color choice is limited, but the resulting appearance harmonizes with the natural aging of the wood.
- A clean wood surface is required: The product is not intended for application over synthetic coatings.
If quick drying, minimal odor, or a specific tone is most important, a modern decking oil may be more suitable. Silvertjära's advantage is long-term protection in cold and damp climates, as well as easy renewal.
Where is Silvertjära most appropriate?
Especially suitable for:
- for wooden decks;
- for facades;
- for piers and boardwalk structures;
- for fences;
- for pressure-treated wood and decking boards
- for outdoor structures that have been exposed to weather conditions for at least one year.
Proper application is important
The surface must be clean, dry, and free of old synthetic coatings. Apply a thin layer with a brush in the direction of the wood grain. On horizontal surfaces, wipe off excess oil that has not absorbed after 20–30 minutes. This is the most important prerequisite for even drying.
Perform work in dry weather, at temperatures above +18 °C, and avoid direct sunlight. If a second coat is needed, it is recommended to apply it no earlier than 48 hours later.
Important! Oil-soaked rags can spontaneously combust. After use, immediately immerse them in water or store them in a fireproof metal container.
Maintenance intervals
The frequency of maintenance depends on the location and operating conditions of the deck. The manufacturer Claessons Trätjära recommends renewing the surface approximately every two years up to nine years of age. For older decks, annual maintenance usually provides the best results.
Decks exposed to intense sunlight or prolonged moisture will require more frequent maintenance than structures in protected areas.
Conclusion
The reason why the tar oil system with centuries of history often outperforms many modern coatings in our climate is not just tradition. It is based on two simple principles:
- The coating contains no water that could freeze and damage its structure;
- Protection is provided from within the wood, rather than forming a film that can crack and peel over time.
In harsh autumns and cold winters, these properties often prove more important than any other coating advantage. Silvertjära Altan requires more careful application and a longer drying time, yet it is one of the most suitable decking protection oils for our climate in the Baltic and Scandinavian region.