Timber Floor Coatings
Timber floor finishes can be grouped into four main categories. Penetrating oils and waxes, curing oils, oil modified urethanes, and polyurethanes, the latter category being available in solvent-based and water-based.
Performance parameters such as durability or resistance to wear can vary significantly within a category as well as between categories. All categories can be re-coated with refurbishment coats.
Hard wax oils are film-forming and can have good durability. They may be one component or two component with an isocyanate cross-linker.
Ease of application and timber colour enhancement are key properties. They can be ‘asthma friendly’ due to being low VOC and the particular types of VOC components used.
Curing oils such as ‘Tung’ or ‘linseed’ are usually selected because of their lower cost and ability to produce a rich timber colour. Gloss levels vary from high gloss to satin and they are not prone to edge bonding. Similar to penetrating oils these finishes are slow curing in cold weather, will darken with age and metalised acrylic polishes are a necessary part of ongoing maintenance activities.
Oil Modified Urethanes (UMO’s)
These solvent-based coatings combine an oil with a smaller amount of a urethane. The higher the urethane proportion, the less the oil properties such as flexibility but the higher the durability.
Gloss levels vary from high gloss to satin and in recent times higher-cost water-based UMO’s providing lower emissions have appeared on the market. All UMO’s darken with age and their slow curing in cold weather needs to be considered.
Polyurethane – Solvent-based
This coating type in the 1 pack moisture cure and 2 pack varieties provide the highest durability and film build of all coating types as well as the highest gloss levels. Gloss levels range from ultra high gloss to matte and some darken less with age. However, there is a strong solvent smell on application and due to the isocyanates present additional precautions are necessary until the coating has cured.
Polyurethane – Water-based
This has the widest selection of sub-categories resulting in a spread of properties with durability from poor to arguably as good as solvent-based polyurethane. Greater care is, therefore, necessary in selection noting that those without acrylic provide higher durability. They are available in 1 and 2 pack options, provide a finish from matte through to gloss and generally darken little with age. Gloss levels range from gloss to matte and some darken less with age. There is less of a strong smell on application in comparison to the solvent-based polyurethane.
FLOOR FINISH SELECTION CHART
|Property||Penetrating oil / wax & hard wax||Oil based finishes||Oil Modified Urethane||Polyurethane Solventborne 1 pack||Polyurethane Solventborne 2 pack||Polyurethane Waterborne 1 pack||Polyurethane Waterborne 2 pack|
|Durability||Low-Med||Med||Medium-High||Very High||Very High||Med-High||Med-VH|
|Ability to accept foot traffic 3 days after coating||Low||Low||Medium||Medium||High||Medium||High|
|Timber colour richness||Low-High||High||High||High||High||Low-Med||Low-Med|
|Darkening with age||High||High||High||High||High||Low-Med||Low-Med|
|Ability to cure in cold and dry weather||Low||Medium||Medium||Medium||High||Medium||High|
|Ability to cure in cold and damp weather||Low||Low||Low||Medium||Medium||Medium||Medium|
|Edge bonding resistance||High||Med-High||Med-High||Low-Med||Low||High||Med-High|
|VOC emission at application||Low-High||Med-High||Med-High||High||High||Low||Low|
|Inhalation hazard when coating is applied||Low||Medium||Medium||Very High||Very High||Low||Medium|
|Odour on application||Low||Medium||Medium||Very High||Very High||Low||Low|