Wood is a natural material, very versatile and full of charm, capable of giving warmth and character to every space, both inside and outside a house: from furniture to fixtures, from cladding to flooring, from fences to garden furniture. To maintain it at its best over time, however, wood needs care and protection. Wood impregnants are one of the most effective solutions for preserving the beauty and functionality of wood. But what is an impregnating agent for wood and what benefits does it really offer?
- What is wood impregnating agent?
- Types of impregnating agents for wood
- How to clean wood before impregnating?
- How many coats of impregnating agent should be given to the wood?
- Can impregnating agent be used to stain wood?
- What to do after impregnating?
- How long does an impregnating agent for wood last?
- What is the difference between impregnant and stain?
- What is the difference between flatting and impregnating?
What is wood impregnating agent?
Impregnating agent is a product formulated to penetrate deep into the wood fibres, protecting it from the inside. Unlike varnishes that create a surface film, impregnating agent is absorbed by the wood, providing longer-lasting protection without altering its natural appearance, leaving the grain visible. To the question “How can wood be protected from rain and sun?“, the answer is, precisely, with impregnation. This type of treatment, in fact, is ideal for protecting wood from:
- weathering: wood exposed outdoors is subject to sun, rain, wind and snow. The impregnating agent creates a barrier against water, preventing it from penetrating the fibres and causing deformation or rotting;
- UV rays: the sun can deteriorate wood, causing it to fade or grease. Impregnating agents contain UV filters that protect wood from the damaging action of sunlight;
- temperature fluctuations;
- moulds: in damp environments, wood is particularly vulnerable to attack by moulds and fungi. Impregnating agents help prevent the growth of these organisms;
- swelling and bubbles: the impregnating agent allows the wood fibres to breathe. This prevents phenomena such as swelling or the creation of bubbles on the surface.
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Types of impregnating agents for wood
There are different types of impregnants. Their use must be evaluated taking several factors into account:
- degree of exposure to atmospheric agents;
- type of wood;
- maintenance intervals;
- position and reachability of the element to be treated;
- desired final effect;
- environmental impact.
The most common types of impregnants are:
- water-based: environmentally friendly and easy to apply, they are perfect for indoor environments and for those looking for an environmentally friendly product. In the Renner Italia Rio Verde range we find:
- theclassic water-based impregnating agent
- thewater-based impregnating gel: designed for vertical surfaces, as it does not drip;
- solvent-based: they offer deeper penetration and are particularly suitable for woods exposed to extreme climatic conditions, such as in marine or mountain environments. In the Rio Verde range there is theclassic solvent impregnating agent;
- hybrids, such as Hybrid Resolve, which is also perfect for very high weathering conditions. Water-based and formulated with high-solids urethanised alkyd resins and acrylate copolymers, it dries very quickly and does not flake.
What are waxy impregnants?
Both water-based and solvent-based impregnating agents can also be waxed: in addition to protecting the wood, they also give it a satin or glossy effect, ideal for those seeking a decorative finish. Rio Verde has two in its catalogue:
In both cases, if a finish is then to be applied, it must also be waxed.
How to clean wood before impregnating?
The procedure changes whether the wood is untreated or wood that has previously been painted or impregnated. On untreated wood:
- dust with hard or soft bristle brushes (depending on the hardness of the wood);
- remove any dirt with mild soap and water (then leave to dry for at least 24 hours);
- give it a light sanding;
- fill in any imperfections;
- Lightly sand the grouted parts;
- remove the dust again.
On already stained or impregnated wood:
- remove any varnish by sanding (or lightly sand if previously treated with oil or impregnating agent);
- fill in any imperfections;
- Lightly sand the grouted parts;
- remove dust.
How many coats of impregnating agent should be given to the wood?
The number of coats to be applied depends on many factors: the type of product being applied, the condition of the wood, exposure to the weather. Generally, on untreated wood, 2 or 3 coats are applied after sanding. On varnished or already impregnated wood, 1 or 2 coats are also applied after sanding.
How long between coats of impregnating agent?
The waiting time between coats can be about 1 to 2 hours, but can vary considerably depending on environmental conditions (with high humidity and little sun, times are longer). Solvent-based impregnating agents generally take longer.
How long does it take for the impregnating agent to dry?
At least 3 hours are required forfinal drying.
Can impregnating agent be used to stain wood?
Since the impregnating agent leaves the grain visible, an opaque colouration, such as would be achieved with a varnish, cannot be expected. However, the impregnating agent can be used to colour the wood. This technique is called staining. Colouring is carried out by means of iron oxides. These, in addition to imparting the pigmentation, protect the wood from damage caused by UV rays.
What are the colours of an impregnating agent?
It depends on the product. In general, there are impregnants with the same colours as the main wood species. 
In theclassic water-based impregnating agents, for example, we find: clear, teak, chestnut-light walnut, walnut, dark walnut, pine-larice, oak, mahogany, green and white. 
In thewater-based impregnating gel: clear, teak, chestnut, walnut, dark walnut, mahogany and white. 
As far aswater-based wax impregnation is concerned: transparent, teak-larice, chestnut-light walnut, walnut, dark walnut, mahogany, old walnut and white. 
Theclassic solvent impregnation: clear, green, larch, mahogany, dark walnut, walnut and chestnut. 
On the other hand, thewaxy solvent impregnation: clear, larch, dark walnut, walnut, medium walnut, white and light walnut. 
Finally,Hybrid Resolve: transparent, larch, chestnut, walnut, dark walnut, white and satin transparent.
What to do after impregnating?
What do you put on after impregnating?
After applying the impregnating agent and waiting for the last coat to dry completely, a top coat can beapplied. This is an optional step, but it is always recommended since:
- increases the strength of wood;
- extends the life of the artefact;
- improves the final appearance.
What finish after impregnating?
You can choose from various finishes. There are several in the Rio Verde product range for both exterior and interior use. Also for interiors, after the impregnating agent you can apply the Vintage Prestige textured effect opaque varnish. With a hybrid finish such as Hybrid Resolve, on the other hand, three coats are sufficient to achieve a complete cycle.
How long does an impregnating agent for wood last?
It is difficult to establish an amount of time that applies to all conditions. As with drying times, the weather variable is crucial. However, it can be said that a good, quality impregnating agent, such as those in Renner Italia’s Rio Verde range, can last for several years. However, it is advisable to reapply the impregnating agent every 2 to 3 years. Even more often if the wood is exposed to extreme conditions or suffers continuous wear. In order to assess whether a new treatment is needed, it is sufficient to rely on sight and touch.
What is the difference between impregnant and stain?
Like impregnating agent, stain penetrates deep into the wood fibres, however, unlike impregnating agent it is not a protective agent. It is usually used for interior wood, to bring out the characteristics of the material and to colour it without covering it with a film of varnish.
What is the difference between flatting and impregnating?
While the impregnating agent, as already mentioned several times, penetrates inside the material, flatting, on the other hand, creates a protective film on the surface. It can be used in combination with the impregnating agent, as a final finish, and is recommended for the treatment of wood that is heavily exposed to moisture and salt, such as nautical wood. The Rio Verde range includes the brilliant Flatting VB 3330.
