4. Criteria when selecting wood and veneer flooring In this chapter we will help you to select the right wood flooring. In addition to optical and aesthetic criteria it is important to bear in mind the criteria that apply to the floor’s specific use. In the overview in Section 4.1 you can see which floors are suitable for different applications as well as the demands placed on flooring. There are technical selection criteria and information on usage of wood flooring subject to heavy loading. Important: Building criteria can also influence the choice of flooring. See the information in Chapter 7 - Sub-floors.
4.1
Overview table when using Kährs’ wood flooring
page 44
4.2
Criteria when selecting the type of wood
page 45
4.3
Selection in terms of sort, style and character
page 47
4.3.1
page 48
Interior design and aesthetics
4.4
Quality as a selection criterion
page 50
4.5
Technical selection criteria
page 51
4.5.1 Thicknesses and constructions 4.5.2 Kährs woodloc® 4.5.3 Impact sound insulation 4.5.4 Thermal conditions 4.5.5 Fire properties 4.5.6 Maximum floor width 4.5.7 Wear resistance 4.5.8 Electrical conductivity 4.5.9 Light sensitivity 4.5.10 Moisture sensitivity
page 51 page 52 page 53 page 53 page 53 page 53 page 54 page 54 page 54 page 55
Selection for public environments
page 55
4.6.1 Suitable products 4.6.2 Maintenance cost 4.6.3 Wiping off surfaces
page 59 page 59 page 59
Reference installations
page 60
4.6
4.7
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4.1 Overview table when using Kährs’ wood flooring Kährs 15 mm wood flooring Chapter 5
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Kährs 7 mm wood flooring Chapter 6
Characteristic and construction
15 mm fully-treated multi layer parquet with Kährs woodloc® joint or traditional joint. 3-layer blocked design with approx 4 mm wear surface.
Special variants
22 mm board with self-supporting structure (with special particle board core) for installation on joists with maximum 600 mm centres. 20 mm board with 6 mm wear surface for public environments.
Applications
Principally domestic. Also for premises subject to heavy wear with additional surface treatment.
Housing and similar premises.
Surface treatment
Fully-treated with silk matt lacquer, UV or natural oil.
Fully-treated with silk matt lacquer, UV or natural oil.
Sub-floor
See Chapter 7
See Chapter 7
Building height
Board thickness (15, 20 and 22 mm respectively) + underlay
7 mm + underlay
Underfloor heating See Section 8.6
Suitable (15 mm planks) See Section 4.2
Very suitable See Section 4.2
Pattern
3-strip board 2-strip board 1-strip board Ship floor Herringbone pattern Dutch pattern.
2-strip board 1-strip board 3-strip board
Types of wood
Hard Maple, European Maple, Birch, Beech, Oak, Red Oak, Alder, Ash, Iroko, Jatoba, Jarrah, Cherry, Merbau, Walnut, Rosewood, Sucupira
Hard Maple, Beech, Oak, Red Oak, Ash, Jatoba, Cherry, Walnut
7 mm veneer floor-boards with Kährs woodloc® joint. 3-layer construction. Wear surface of thin hardwood veneer, intermediate layer of HDF and base layer veneer.
4.2 Criteria when selecting the type of wood Type of wood - structure/colour/properties
Country of origin
Hardness
Colour change
Hard Maple (Canadian Maple): Light yellowish-brown to dark yellowish-brown wood Dense pores with brownish heartwood. Grain in thin streaks. Hard Maple reacts more than other types of wood to variations in room climate.
North America
4,8 (3,2– 6,9)
Goes yellow
European Maple: Light yellow to yellowish-brown wood The heartwood is brownish. Dense pores.
Central Europe
3,0 (2,3– 4,5)
Goes quite yellow
Birch: Whitish-grey to light brown wood with mother of pearl structure. Brown streaks in the heartwood. Dense pores.
Sweden
2,6 (1,6- 4,0)
Goes yellow
Beech: Light yellowish-brown to reddish-brown wood. Dense pores with reddish-brown heartwood. Beech has a very discrete grain. Beech reacts more than other types of wood to variations in room climate.
Sweden
3,8 (2,0- 5,9)
Goes yellow
Oak: Brown to dark-brown wood. Porous with white surface wood. Marked grain.
Sweden
3,7 (2,2-5,9)
Goes yellow
Red oak: Yellow to slightly pink wood with the same structure as common oak. Porous with white surface wood.
Central Europe
3,7 (2,4-6,9)
Goes yellow
Alder: Yellow to slightly red wood. Brown streaks in the heartwood. Dense pores with fine grain.
Sweden
2,1 (1,5-2,8)
Goes quite yellow
Ash: Light yellow to yellowish-brown wood. Brown heartwood. Porous. Marked grain.
Sweden
4,0 (2,8-6,2)
Goes yellow
Iroko (Kambala): Golden-brown to dark-brown wood with narrow grain. Dense pores.
Africa
3,5 (1,4-5,4)
Goes dark/quickly
Jatoba: Reddish-brown porous wood with grey/white surface wood. The grain is dense and moderate.
Brasil
7,0 (4,5-14,1)
Goes dark/quickly becomes bright red
Jarrah: Reddish-brown to dark-brown wood. Dense pores.
Australia
4,7 (2,9-9,0)
Goes quite dark
Cherry (Black Cherry): Light red, green to dark reddish-brown wood. Contains black streaks (gum). Dense pores with white surface wood.
North America
3,6 (1,7-6,2)
Goes dark/quickly becomes bright red
Merbau: Yellowish-brown to brown or blackish-brown wood. Visible porosity.
Indonesia
4,9 (2,7-7,8)
Darkens/goes red
Walnut: Brown to blackish-brown wood. Dense pores with white surface wood. Varied and significant grain.
North America
3,4 (2,0-5,1)
Goes yellow
Rosewood: Pink to red, light brown to brown. Dense pores with whitish-grey surface wood.
South Africa
4,6 (3,5-6,1)
Goes dark/quickly becomes bright red
Sucupira: Dark brown wood. Dense pores with slight grain.
Brasil
5,6 (2,8-7,8)
Little change
7 mm wood floor:
See the respective types of wood above
5,0-6,0
See the respective types of wood above 45
The hardness of wood flooring varies according to the type of wood and is measured according to the Brinell scale. A steel ball with a diameter of 10 mm is pressed against the surface of the wood with a predetermined force and time. The residual impression is then measured and the actual Brinell hardness calculated.
The harder the wood, the higher the value. The structure of wood means that relatively large variations occur. The stated value is an average of a large number of measurements taken on a finished floor.
16
14
12
10
8
6
4
2
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Jarrah
Merbau
Jatoba
Rosewood
Cherry
Red oak
Alder
Beech
Walnut
Sucupira
Iroko
Oak
Birch
Ash
Hard Maple
European Maple
0
4.3 Selection in terms of grading, style and character Most of Kährs wood flooring is available in different grading. This has nothing to do with the quality of the wood. By grading the different strips according to appearance we are able to offer flooring with a number of different characteristics. By using wood as a raw material, most wishes related to design can be accommodated. The choice is therefore primarily a question of taste. But the choice also affects how the floor will be used and in which environment it will be installed. • The structure of the wood, together with its hard ness, determines how durable the floor is. The Brinell value, measured to indicate the hardness, is an average value of a number of measurements. Major or minor variations can occur within each type of wood. See Section 4.2.
• Lively, natural products and strongly structured types of wood such as Oak are not so optically sensitive as light, evenly grained types of wood such as Hard Maple even though the latter is slightly harder. • When choosing the floor, appearance and the style of décor are equally important as the practical aspects. It is different if a wood floor maintains a low profile in the room so that furniture and other objects are more prominent, or if the if the floor is to character ise the entire room.
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Kährs has divided its products into three styles of wood flooring to be able to offer the customer the wood floor that best suits the person’s lifestyle and personal taste: Style Selection, Life Selection, Classic Selection and Design Selection. This is where everybody can find their own highly-personal floor.
Style
Life
Selection
Selection
Kährs Style Selection Stylish wood flooring in an even and discrete grade that provides a calm and timeless impression. These always work when it is not the floor but the furniture and other interior designs that set the tone. The floor plays a more unobtrusive role in this case. Wood flooring is designed to lift your interior design. Initially, certain Stockholm products may appear to have quite a range of colours but these even out quite quickly.
Kährs Life Selection Wood flooring with knots offers a very natural feeling and is produced with exciting variations in colour and structure. These floors appeal to people who wish to express a natural lifestyle.
4.3.1 Interior design and aesthetics The floor constitutes the largest part of the interior design in a house. There should therefore be harmony between the floor colour and the dominant colour of the rest of the interior design. In the product brochure you will find colour composition.
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Classic Selection
Kährs Classic Selection Wood flooring with charm and lustre from times gone by in both classic patterns and new, modern combinations.
Colour scale Yellow/brown colours
Red/brown colours European Maple
Hard Maple
Ash
Birch
Oak
Iroko
Sucupira
Walnut
Beech
Alder
Red oak
Cherry
Rosewood
Jatoba
Merbau
Jarrah
Note the colour changes in the different types of wood. Refer to Section 4.2.
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4.4 Quality as a selection criterion The quality of a wood floor is not always so easy to recognise optically. It concerns more than the characteristics that are defined in the standard for finished wood floors. Form stability Does the board maintain its shape during the normal climatic variation that occurs between summer and winter? The difference between high quality wood floors and cheap alternatives is not always evident until after a period of use. The correct moisture content in the different layers during manufacture is essential for the board shape, stability and quality over many years of use. The multi layer construction’s natural barrier function is distributed evenly compared with a solid floor’s major movements. Wood flooring of Beech and Hard
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Maple swells and shrinks more than other types of wood. Underfloor heating causes increased drying and this results in extra shrinkage. If the climate is cold and dry, such as in Sweden, gaps between strips and boards may occur. Quick and efficient installation: A good fit and straight edges makes installation problem-free. You always get the perfect result with Kährs woodloc®. Laying the floor is easy and quick which makes the installation efficient both for the professional and the DIY enthusiast. Healthy living environment and ecological attitude: Properly treated wood floors are the natural choice for those suffering from asthma and allergies thanks to the low natural emissions. They are also very easy to keep clean. Refer to Section 3.3.3.
4.5 Technical selection criteria 4.5.1 Thicknesses and constructions K채hrs wood floors are available in different thicknesses. Suitable thicknesses for homes are 7 mm or 15 mm. The following shows which thicknesses are available, how the planks are constructed and how they should be installed.
7 mm (veneer floor) Number of layers: 3 (base layer - veneer/middle HDF layer/surface layer) Surface layer: approximately 0.6 mm veneer (HDF intermediate layer absorbs the loading) Installation: Floating installation on a clean, level, dry and solid subfloor such as concrete, chipboard or wood. Suitable everywhere thanks to its low installed height.
15 mm (standard board) Number of layers: 3 (base layer - veneer/middle layer/surface layer - hardwood) Surface layer: approximately 4 mm Installation: Floating installation on a clean, level, dry and solid subfloor such as concrete, chipboard or wood.
20 mm
22 mm
Number of layers: 3 (base layer - veneer/middle layer/surface layer - hardwood)
Number of layers: 3 (base layer - veneer/middle - chipboard/ surface layer - hardwood)
Surface layer: approximately 6 mm
Surface layer: approximately 4 mm
Installation: Floating installation on a sub-floor such as concrete, chipboard or wood.
Installation: Floating installation directly on joists with maximum 600 mm centres. The studs must be clean, level, dry and solid.
15 mm (pattern floor) Classic: Amsterdam, Rotterdam, Toledo Number of layers: 4 (base layer - veneer/two middle layers/surface layer - hardwood) Surface layer: approximately 4 mm Installation: Floating installation on a clean, level, dry and solid subfloor such as concrete, chipboard or wood.
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4.5.2 Kährs woodloc®
Kährs wood flooring with woodloc® joints offers several benefits Strength Kährs woodloc® joints are stronger than traditional glued joints. The mechanical joint retains its strength during changes in the interior climate. This means that the joint between the boards remains tight during normal climate variations and loading. This property is retained throughout the entire life of the floor. Flexibility Since no glue is used it is a simple matter to replace damaged boards. Only the damaged board needs to be replaced. The undamaged boards can be put back in place again after the repair.
Mechanical joint Thanks to the mechanical joint’s immediate locking function, the line in the installation will be straight after two rows have been installed. No string line is required. The rows of planks align themselves and the floor can be walked on and used immediately after installation. Glued joints require a certain drying time to achieve their maximum strength. Woodloc® has its full strength immediately and needs no drying time. The obvious choice if you have underfloor heating is flooring with woodloc®.
The sub-floor can be easily accessed if repairs are required. This allows repairs to be made at a later date - not such a simple matter in the case of glued floors. In everyday use Kährs woodloc® offers flexibility and is therefore an economic option if an accident occurs or, for example, there is water damage to a small section of the floor. Highest precision The precision resulting from manufacturing makes it easy to lay the boards with a perfect result. Kährs Woodloc® has sharp edges, which means that the wood floor is virtually free from visible joints. Kährs original design construction with an intermediate layer of pine utilised to provide the best shape stability and climate resistance.
Wood flooring is beautiful. It has never been so easy to install a real wood floor without visible joints.
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4.5.3 Impact sound insulation The normal requirements for impact sound insulation according to BBR apply in Sweden. There is a range of technical solutions to achieve the required value.
Kährs have previously tested a number of floors with regard to impact sound insulation. The following shows the results from these tests performed by the Swedish Testing and Research Institute, SP.
The flooring underlay is placed between the concrete joists and the wood floor. This should be installed edge-to-edge without any overlap. When the underlay is used in combination with a vapour barrier, the underlay should be placed on top of the vapour barrier.
It is also possible to meet higher requirements in connection with solid joist structures. The wood floor in itself does not provide any noticeable contribution to impact sound insulation.
Description of the floor
Impact sound ΔLw (dB)
7 mm wood floor + floor paper L400 7 mm wood floor + Cellofloor 2 mm 7 mm wood floor + Cellofloor 3 mm 7 mm wood floor + Airolen® 1,8 mm 15 mm Kährs wood floor + Cellofloor 2 mm 15 mm Kährs wood floor + Cellofloor 3 mm 15 mm Kährs wood floor + Airolen® 1,8 mm 15 mm Kährs wood floor + Airolen® 3,0 mm
16 19 19 18 17 18 17 18
Impact sound Class 7 7 7 7 7 7 7 7
Airborne sound ΔRw (dB) -2,0 -2,0 -3,0 -2,0 -1,0 -1,0 -1,0 -0,5
4.5.4 Thermal conditions A wood floor is warm to walk on in bare feet because ‘of the floor’s low ability to conduct heat. Despite this, a wood floor has sufficient heat conductivity to
make it suitable for laying on underfloor heating (see Section 8.6).
4.5.5 Fire properties Kährs wood flooring meets the Swedish requirements for class G - the highest fire rating class according to the National Board of Housing, Building and Planning’s Building Regulations BBR 94. The requirements are met by all wood flooring with or without surface treatment. This is shown in a study conducted by Trätek. Floor
material is fire-tested according to Nordic method - NT Fire 007 - and complied with the test by a good margin. The result is shown in “Kontenta”, (summary of results from Trätek, the Swedish Institute for Research in Wood Technology) “Brandklassade trägolv” 9604029.
4.5.6 Maximum floor width The maximum width for wood flooring in a floating installation is 12 m. If the width is greater the floor should be divided using expansion joints. There is no limitation if the planks are glued to a concrete floor. If the surface onto which the wood floor is glued has limitations in terms of maximum width that is less than the above then the limited width will apply.
For example, a room with a width of 4 m shall have an expansion joint of 4 x 1.5 mm = 6 mm between the floor and all fixed objects.
!
The size of the expansion joint in mm can be calculated using the formula: 1.5 mm per metre of floor width
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4.5.7 Wear resistance The wear resistance will depend entirely on the surface treatment. In a normal domestic environment our lacquered floors will last a long time without further treatment being necessary. According to HusAMA98 Table MDB/1 the value shall be at least Class 5. Kährs’ lacquered products meet this by a good margin. The same applies to our UV-oiled floors.
Natural-oiled floors should be maintained to maintain their gloss and wear resistance. Natural-oiled and waxed surfaces become even stronger if regularly maintained. Where there are greater demands for wear resistance (public environments) the treated wood floors are provided with a further protective coating after installation.
4.5.8 Electrical conductivity A wood floor’s electrical conductivity is low. Wood had good electrical conductivity resistance, because of its insulating capacity, wood offers protection when using electrical machinery. The insulation is not so strong that it will prevent a static charge being built up by
rubbing shoe soles against the floor for example. These properties make wood floors suitable for computer suites. Oiled floors are normally used in these areas.
4.5.9 Light fastness/UV ageing Wood is a natural material which, during the first few months, matures to its natural colour. This characteristic underlines the beauty and character of a real wood floor. To produce an even surface, rugs should not be
Maple
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Beech
laid on the floor during the initial months after installation. If there are already light patches from carpets etc, these will mature when they are exposed to daylight.
Ash
Birch
Types of wood
Change
Types of wood
Change
Beech Oak Ash Hard Maple Birch Jarrah Jatoba
Goes yellow Goes yellow Goes yellow Goes yellow Goes yellow Goes quiite dark Goes bright red
Merbau Cherry Alder Sucupira European Red Oak European Maple Iroko
Goes red Goes very dark quickly Goes quite yellow Changes very little Goes yellow Goes quite yellow Goes dark
4.5.10 Moisture sensitivity Because of their open cell structure when dried, certain types of wood have a greater capacity to absorb and dissipate moisture than other types. Beech and Hard Maple are among these. See Section 8.6.2. It is particularly important to consider this when cleaning installed floors with a damp cloth etc.
!
In areas where there is a risk of water being spilt and this is not wiped up in time, we recommend additional surface treatment after the floor is installed. See Sections 9.1.1.1, 9.1.2.1 or 9.1.3.1.
4.6 Selection for public environments Wood and veneer floors from Kährs are generally suitable for use in public environments. The following issues should however be considered: • What is the area going to be used for? • What is the level of foot traffic in the building? • What type of wood has the right degree of hardness? (Refer to Section 4.2)
• How significant is the thickness of the surface layer? • Is gluing to the sub-surface the better option or is a floating installation preferable? • What type of surface treatment should be chosen - lacquer or oil? • What is the entrance zone solution for removing grit and moisture from shoes?
Kährs Beech Cambridge, Bad Berka Hospital, Germany.
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Kährs Oak London as a design component in a British fashion shop chain.
Kährs Hard Maple Stockholm, Art Gallery in Birmingham, England.
Kährs plank with a 6 mm wear surface (see Section 5.3).
Kährs Oak Monte Carlo with natural oil, at the environmental centre, Neckar-Fils, Germany.
Kährs Birch Monte Carlo, at the Café-Bar Metropolitan in Esslingen, Germany.
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K채hrs Beech Cambridge, oil finished, Rebmannshof Birnau, Germany.
K채hrs 7 mm wood flooring.
K채hrs 7 mm wood floor Beech 2-strip, Firma Schuttheiss Werbemittel.
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K채hrs Oak Monte Carlo
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4.6.1 Suitable products Kährs wood floors that can be used: 20 mm multi layer board with 6 mm surface layer This is designed for environments that are subject to considerable wear, where several re-sanding operations and significant material removal down to clean wood may be necessary. 15 mm with 4 mm surface layer This floor can be used in environments where wear is less and sanding with a normal amount of material removal is justified.
4.6.2 Maintenance cost It is important to follow the care instructions for environments where there is heavy wear. In certain premises such as in bars, department stores and libraries, special consideration is required when selecting wood floors, surface treatment, maintenance systems, inspection and cleaning.
7 mm wood floor: Since this material cannot be sanded it is preferably used in environments with low-level wear, nurseries and offices where there is little wear and where it is sufficient to protect against increased wear with additional surface treatment.
!
Kährs factory treatment is designed for domestic use and additional treatment is always necessary for floors in public environments.
!
Maintenance costs during the life of the floor in public environments are up to 5 times as much as the purchase and installation cost. As a consequence, a relatively exclusive floor can be selected without this having a significant effect on life-cycle cost.
The maintenance and cleaning of wood floors is more important than the thickness of the surface layer. Entrances should be designed with particular care.
4.6.3 Entrance Mat Zones Effective entrance mat zones are very important to the new wood floor’s life. All grit and moisture should be removed from the soles of shoes to protect the floor. The best effect is achieved if this is done in three stages.
The best entrance design makes it possible to walk at least three steps on each mat – the more the better. This method not only saves the floor but also makes day-today cleaning easier.
• Coarse scraping facilities outside the entrance. A scraper mat with rubber laminates will remove the coarsest particles. • “Plastic turf” such as Astroturf that removes the remaining particles. • Textile mat that removes moisture and remaining grit from shoes.
The cost that is incurred in designing a good entrance pays for itself many times over as a consequence of lower maintenance costs. Obviously the mats need to be cleaned regularly.
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4.7 Reference installations
Activity Butterickshuset, Malmö Butterickshuset, Malmö Linbärets Förskola, Malmö Kv. Östersjön, Malmö Riksbanken, Malmö Din Sko, throughout Sweden Hotell Skansen Intensia, Malmö Max Mathiesen Mäklare Kronprinsen Bowling, Malmö Seating Concept Ingvar Kamprad Designcenter, Lund Bowlinghall, Malmö Lindvallens Högfjällshotell Hotell Foresta, Lidingö Hotell Selma Lagerlöf, Sunne Tingshuset, Jakobsberg Sara Winn, Gävle Carlstad Conferenscenter, Karlstad Högskolan, Malmö
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Product
Surface treatment
Oak Oak Ash Oak Beech Oak Oak Oak Oak WL Oak WL Ash Ash Merbau Oak Jarrah Oak Oak Oak Merbau
Natural-oiled UV-oiled/lacquered Lacquered Lacquered Lacquered Natural-oiled Natural-oiled Natural-oiled Natural-oiled Lacquered UV-oiled Lacquered Lacquered Lacquered Lacquered Lacquered Natural-oiled Lacquered Natural-oiled
SE-banken, Malmö Restaurang Gårdsvägen Hotell Quality, Nacka Orgelpipan Scania Sandhamns Kunskapsskolan, Enskede Hästens Sängar
Offices Apartments Kindergarten Offices Offices Shops Corridors Offices Offices Restaurant Furniture shop Workshop premises Bowling hall Hotel rooms Hotel rooms Hotel rooms Courthouse Hotel rooms Vänersalen School premises and library Office premises Restaurant Hotel rooms Offices Offices Värdshus School premises Shop premises
Beech Ash Oak Oak Oak Oak Oak Oak Walnut
Natural-oiled Lacquered Natural-oiled UV-oiled UV-oiled Lacquered Lacquered Natural-oiled Natural oiled/ Lacquered
Infra Hotell Winn Din Sko, Solna
Businesscenter Hotel rooms Shop premises
Oak Oak Oak
Lacquered Natural-oiled