Glulam has many more possibilities than just the visible wood look, lacquered or untreated. If you treat the glulam surface it can take on a new form or look. A dramatic black top coat, a whitewash or silky gray steel are just some examples of finishes that both protects and enhances the look of your glulam.
Glulam ages beautifully, but it does so best when the surface has been treated, both indoors and outdoors. You can surface treat glulam using the same means and methods used for ordinary wood. What you choose depends more on how you want it to look like and what protection surface treatment you are looking for. Impregnated glulam provides effective protection against rot but must be treated and maintained in the same way as normal glulam.
A heated premises requires no surface treatment of glulam unless you want to have a different color other than the glulam’s own yellowish white. All types of finishes can be used, just as for in conventional wood - topcoat, gloss, wood stains, clear coat or oil. When painting for maintaining the wood, then it should primarily be the same type of surface treatment that was used originally.
In rooms with high moisture levels, such as swimming pools and wet areas or other premises with risk of condensation, then you should be restrictive with using surface treatments that require extensive pre-treatments during maintenance, for example, topcoat and clear coat. Its recommended to choose the appropriate wood stain or oil, which is more maintenance friendly.
Untreated glulam and glulam that is surface-treated with a non-pigmented treatment (colorless wood oil) becomes gray after a period of outdoor exposure. An untreated wood or poorly maintained surface can lead to increased moisture levels by rain, wet snow, melting or splashing water, which in turn can eventually cause discoloration and cracking.
The main destructive factors in outdoor conditions are rain, wet snow, sunlight and soil moisture. Weather changes from rain to sunshine puts great pressure on weather exposed surfaces. Glulam needs to be protected from rain.
In sunlight, a surface can quickly obtain a high temperature - dark surfaces can reach up to 70 ° C. This causes the surface to substantially dry out, which as the wood moves results in the risk that the surface layer can gradually begin to crack.
Glulam products that will be exposed to the outdoor elements, for example, exterior paneling boards, are available industrially surface treated and you can then finish or paint them after application. Such treatments should have a primer thickness of at least 60 µm (microns) dry film. 60 micron is equal to 0.06 mm, or 1 liter of paint for around 6 m2.
Minor cracks, or so-called dry cracks, are generally so small and superficial that they do not cause any major inconvenience. Larger cracks allow water to quickly penetrate the inner parts of the glulam. They are also pockets of moisture-retaining dirt and debris that can accelerate the attack of microbial growth.
On horizontal surfaces and in especially in larger cracks where water can pool, there is a great risk of rot. Cracks that appear should be filled with suitable material to prevent further cracking. With the help of the right structural design from the start, prolonged moistening can be minimized. Heating with radiators or warm air pumps can minimize the risk of local drying and cracking
Rapid moisture changes can be suppressed with moisture protective coatings or treatments. The end surfaces absorb moisture substantially faster than the other surfaces. Bearing glulam beams that have weather-exposed surfaces should be provided with a cladding such as ventilated sheet metal cladding or exterior panel boards, especially on end surfaces and on the sides. If this is not possible, the exposed surfaces should regularly be coated with a moisture protection, for example penetrating oil or wood protection treatments.
By using a pigmented coating treatment, you get better protection against UV radiation. The higher the pigment content, the better the protection - a topcoat provides optimum UV protection and durability. Wood stains give a specific but limited UV protection and less durability compared to topcoat systems. Clear coat and colorless wood oil generally provide insufficient protection against UV rays and should not be used on glulam that is exposed to the outdoors, that is hard to replace, unless you are looking to achieve a weathered look. Clear lacquer on the outside of glulam can eventually start to crack and flake off, which complicates maintenance. There are clear varnishes with built-in UV filters. Glulam can also be coated with a protective layer of polyurethane.
The maintenance of buildings accounts for a significant part of their total cost. To nurture buildings requires understanding, knowledge, care and judgment. A building or facility not properly maintained, degenerates. Wooden bridges have regulatory requirements for regular inspections.
The goal with maintenance is to preserve. Regularly reviewing the various parts of the building are included in the general maintenance and are necessary to detect problems or damage in time, to determine the appropriate maintenance measures.
There are no set maintenance intervals for different materials and designs. External influences can vary so much that it is impossible to generally specify how often a maintenance review needs to be performed, or the maintenance intervals for various measures in individual cases.