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European Journal of Applied Sciences – Vol. 13, No. 02

Publication Date: April 25, 2025

DOI:10.14738/aivp.1302.18510.

Sahin, C. K., & Merdan, R. (2025). Properties of Clear Coated Spruce (Picea orientalis) and Beech (Fagus orientalis) Woods for

Evaluating Outdoor Utilizations. European Journal of Applied Sciences, Vol - 13(02). 165-175.

Services for Science and Education – United Kingdom

Properties of Clear Coated Spruce (Picea orientalis) and Beech

(Fagus orientalis) Woods for Evaluating Outdoor Utilizations

Candan Kus Sahin

Suleyman Demirel University, Architecture Faculty,

Department of Landscape Architecture Isparta, Turkiye

Rahim Merdan

Isparta University of Aplied Sciences, Keçiborlu Vocational School,

Department of Interior Design, Isparta, Turkiye

ABSTRACT

It has become an important issue for protecting wood that is not harmful to users,

while wooden design elements provide many opportunities and amenity to visitors.

Some new types of wood-protecting agents have gained importance due to their

low-toxic chemical formulations. The study presents the experimental study on

outdoor exposure impact on clear coated of two different of Spruce and Beech wood

species. It was found that increasing coating number is usually having positive

effects, lowering the water absorption of both spruce and beech woods. The lowest

water absorption value of 1.7% found at fifth-time coated beech wood, which shows

approximately 97.2% lower than the control sample. However, increasing coating

time (durations) was found to have further lowering effects on water absorption for

beech wood species. It was found that the three-month duration of weathering was

not affected by the surface scratch resistance (hardness) of control spruce and

beech woods, while it is usually increasing effects on waterborne varnish-treated

samples regardless of treatment conditions. This is clearly indicating

physicochemical modification and creating tension on wood surfaces in outdoor

conditions. However, weathering significantly affects the surface color and gloss

properties of selected wood samples. The increasing coating layer was found to be

not affected by improving lightness values for spruce wood. The similar trend was

also observed with treatment time up to 3.0 min, and beyond this level, the wood

surfaces were found to be lighter (ΔL: + values). Moreover, varnish treatment

variables (coating layer and time) were also not any improvement effects found for

beech wood. The lowest ΔL value of-9.78 (in metric) was found for sample Be,

followed by B4 (ΔL:-9.38) and B5 (ΔL:-9.0), samples, respectively. It is important

that the surface total color difference (ΔE) of wood substrates appeared to be well

correlated with coating number and time of duration for both spruce and beech

woods. It was realized that increasing the coating number is not effective for

improving gloss properties for spruce wood, while some variations in glossiness for

beech wood could be realized by changing the treatment parameters.

Keywods: Waterborne varnish, landscape elements, beech, spruce, weathering, color

properties.

INTRODUCTION

While the landscape describes an environment, consists of mostly greenish infrastructures, the

architecture evokes a constructive work that was completed from the very beginning and will

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European Journal of Applied Sciences (EJAS) Vol. 13, Issue 02, April-2025

age over time [1,2]. It has already been well established that wooden material is an effective

material for both architects and users in planning space by positively addressing people's

feelings, particularly aesthetic features, which are very important even though the pattern

changes according to the cutting direction of the wood [1-3]. It has well-presented that wood

can be blended naturally with landscape elements to create a masterpiece with challenging

projects. Because of its versatility, variety of natural colors, and flexibility properties, it

could be used in numerous applications to provide a natural way to add value with a level

of warmth and soften with possibilities for creating unique elements [1,4,5]. Some of the

examples of areas where wooden materials are generally preferred are urban and

neighborhood parks, residential gardens, children's playgrounds, sports fields, squares, zoos,

curbing structures, garden beds, walkways, retaining walls, borders and edgings, pergolas,

planter boxes, and so on. However, wood can act as the focal point of green infrastructures,

gardens, yards, and other landscape elements [1-5]. Hence, wood could be preferred for

multiple purposes in landscape architecture applications in interior and exterior spaces,

creating options for designers for the place of use, usage expectations and desires thanks to its

many types [1,3,5].

However, the use of wood in interior and exterior design is only possible with well-known wood

materials. The use of the material in design disciplines will be possible by revealing its relations

with other materials, extending its usage life, and revealing the properties of wood in terms of

aesthetics and functionality [1,6,7]. Moreover, landscape architects should be considered

environmental products that measure and verify the life cycle of products with the need to

convince the people to do it. In this context, selecting the correct surface coating agent can

enhance the beauty of wood pieces, which requires considering the dominant tones in the finish

[1,4,5].

There have been numerous surface protective agents, available on the market. But it should be

considered the right choice in forming a protective layer in accordance with the end use of the

wood material. The most commonly used varnish types are two-component solvent-based (oily

varnishes) that are usually cured by a combination of both physically and chemically [4,5, 8-

10]. But these types of agents contain some toxic chemicals (volatile organic compounds; VOC),

which are released (emitted) during the service of wood products. Therefore, many varnish

types with more environmentally friendly formulations have emerged recently.

The water-based (waterborne) varnish systems, whose solvent is water instead of oil or

alcohol, have become increased gradually in recent years [9,11,12]. Although these systems

have some advantages over synthetic solvent-based varnish systems, they also have some

drawbacks that their effectiveness is limited when applied to only a single layer, could cause

some discolorations on certain woods (tannin contains woods), may not be effective for some

wood types (resinous woods), and needs to apply multiple layers for effective protection.

Numerous studies have already been conducted for selecting and application of wood

substrates for outside use [1, 4,5, 9-13]. It was reported that hardwood and softwood species

show a systematic trend to surface discoloration that occurs and is clearly visible as a natural

texture with natural weathering progress. However, the degree of changes varies with different

wood species [3-5].

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167

Sahin, C. K., & Merdan, R. (2025). Properties of Clear Coated Spruce (Picea orientalis) and Beech (Fagus orientalis) Woods for Evaluating Outdoor

Utilizations. European Journal of Applied Sciences, Vol - 13(02). 165-175.

URL: http://dx.doi.org/10.14738/aivp.1302.18510.

Although numerous literatures can be found for surface protective agents for woods, a

systematic approach for the application of water-based varnish systems on specific woods

under outdoor conditions is clearly needed. To find out, selected wood specimens were

subjected to waterborne varnish treatment and used to determine resistance against natural

weathering conditions. After specific time to outdoor exposure, the level of photo-discoloration,

surface hardness and water absorption properties were determined based on controls.

Therefore, the objective of this study is to discuss some of the most common concepts of surface

protection of wood in the context of weathering and suitability for outdoor use, emphasized in

landscape applications. Their importance in predicting the selected wood-weathering

interactions of two different species is discussed herein.

MATERIAL AND METHODS

Spruce (Picea orientalis) and Eastern Beech (Fagus orientalis) woods were selected for

investigation. The spruce and beech woods were acquired from the Black Sea region in Turkey.

The samples were cut into small pieces (5x5x1 cm) and dried in laboratory conditions to an air- dry level (12%) before the experiments. A waterborne type colorless varnish used in this study

was purchased from a retail store. The varnish was used as an emulsion formulation that

belonged to the company’s prospective, as supplied without any further purifications.

The varnish applications on samples were carried out for two different procedures. In one

procedure; in a soaking for 1 to 5 minutes, separately, then the drying was carried out at room

temperature for 8 hours. In the second procedure, in a soaking for 1 to 5 times, separately, the

drying was carried out in each stage for 2 hours and final drying in a room temperature for 8

hours. The all varnish-treated samples were soaked in distilled water at room temperature (23

°C, ±2) for 24 hours, and water absorption (WA%) was calculated. The water absorption

measurements were made with a digital balance, accurate to ± 0.01 gr. After the termination of

each experiment, the percentage maximum water intake was calculated by using the following

equations:

Max. water absorption (%) = 100*(Wet weight - Oven dry weight)/Oven dry weight (1)

The natural weathering tests were conducted on both control and waterborne varnish treated

samples for three months of duration on the south side of Sobu Heights in Isparta, Turkey. The

coating film hardness was determined by the pencil hardness (scratch resistance) test

according to the standard ASTM D3363. This testing checks one standard for film hardness by

comparing the ability of a graphite/clay pencil led to scratch the cured film. In the instrument,

the pencil is held firmly against the film at a 45° angle and pushed away from the operator. The

hardest pencil is applied first. The first pencil that does not mark the film before being marked

determines the “pencil hardness” of the film. This is expressed by the number and/or letter

denoting the hardness of the pencil.

Wood color studies are generally quantified by the CIE L*, a*, b* standard (1976) created by the

Commission Internationale de l’E ́clairage with a three-axis system, i.e., lightness (L*) from 0%

(black) to 100% (white); a* from green (-a) to red (+a); and b* from blue (-b) to yellow (+b).

The CIE color parameters of L*, a*, and b* were determined for un-weathered control and three

month weathered samples by the CIE L,a,b (1976), and their corresponding variations with the