Frequently Asked Questions

What are the disadvantages of solvent-based finishes?

Solvent-based polyurethane coatings pose severe health risks to flooring contractors, other trades on site, during and after the floor has been coated, and occupiers of the property.  These coatings contain high levels of solvents, up to 80%, and chemicals such as Toluene Di-isocyanate, Formaldehyde, Xylene and Benzene.  This means they have to be labelled variously as Toxic, Poison and Flammable or at a minimum with Warning and Caution labels.   Various studies have associated these chemicals with cancer, nervous system disorders, depression, chronic fatigue, dermatitis, and lung disease.  Supplier of H & S equipment will only recommend the use of an independently supplied air system whenever solvent-based finishes containing isocyanate are used because the dangers are such that it is not possible to be protected using a normal face mask.  The dangers from isocyanate and solvent can persist after the finish has dried whilst it is in the curing phase which lasts up to 14 days, or potentially longer in adverse drying / curing conditions.

In addition to potential health issues there are drawbacks to solvent-based products with regard to their appearance and on-going performance.  Solvent-based finishes are supplied predominantly as gloss finishes as reduced gloss coatings can be more difficult to apply and get good results from.  The appearance obtained darkens the floor bringing a yellow tinge and a plastic looking film.  As time passes the finishes react to UV light becoming darker with a distinct yellow colour.  There is also the potential problem of edge bonding to consider where movement of the timber due to moisture content fluctuation can result in cracks developing in the floor.  This occurs where the boards are stuck together due to the solvent based finish penetrating into joints between boards.

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What are the benefits of Bona water-based finishes?

  • Non-toxic and with no hazard classification
  • Waterborne and non flammable
  • Pose no health risks during or after application
  • Quicker re-occupation
  • Non–yellowing; no darkening / yellowing of the finish over time 
  • Minimise the risks for edge bonding
  • Maintain and enhance the natural appearance of the timber
  • Products available to meet P3 slip resistance without the need for onsite additives
  • Products available in Gloss, Satin, Matt, Extra Matt and Natural, a flat Matt 6% sheen level

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What about VOC’s?

Bona water-based finishes meet the strictest world standards for Volatile Organic Compounds.  All Bona finishes contain less than 100 grams per litre or 9.9% - well within the EU Standard & Green Star requirements.  In the case of Prime Classic the solvent content is just 2.3% (25 g/Lt).

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Are water-based finishes more expensive?

The difference between using a water-based finish and a solvent finish is usually about $4 - $6 per m².  However, the many benefits of using Bona non-toxic water-based finishes far outweigh the dollar cost difference as noted previously.

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What about wear resistance?

Bona Traffic HD and Traffic exceed the wear resistance of solvent-based products and Bona Mega can be seen to wear as well as most solvent products and better than othersThe latest product Bona has introduced is Bona Traffic HD which has only 44g / Lt VOC content but gives over 60% better wear resistance than the original Bona Traffic combined with full use of commercial floors only 24 hours after the last application.  Practical experience clearly proves that the products can withstand the requirements of domestic and commercial sites.  It is important though not to lose sight of the fact that resistance against abrasion is not the only feature of wear resistance.  Many companies talk of resistance from Taber Abrasor tests where resistance against an abrasive is measured but this takes no account of scratch resistance, resistance to impact or scuff resistance.  Many materials testing organisations such as CSIRO in AU and TRADA in the UK have tried to correlate Taber Abrasion and other tests against on-site real life experience and found that whilst there is a broad correlation it is by no means absolute.

Recent examples of commercial projects in Australia include Traffic HD Extra Matt at the Melbourne University Architecture faculty, the entrance hall & Kings Hall at Old Parliament House in Canberra where Bona Traffic Anti Slip & Traffic HD were used and 10,000 m2 of Bona Traffic Matt at the National Gallery, Victoria at their St Kilda Rd and Federation Square galleries.

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How do I specify Bona products?

Full details of the use of Bona products can be found within the product datasheets.  There is also a series of specification documents for the various finishes under the Specifications tab at the top of this page.  With the specification sheets any choices you need to make are highlighted in blue text but other than this these documents are  designed to be ready for use.
 
It is possible that contractors will suggest that stains or solvent-based primers from other companies be used in conjunction with Bona finishes.  If products other than Bona materials are used you should ensure that samples are prepared and that the specification is tested so that it meets your requirements.  Bona, like other companies within the coatings industry, cannot support their products when used as part of a 'mixed' specification with stains or coatings from other manufacturers.

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Why specify a sealer?

Although Bona top coats can be used directly on bare timber, we strongly recommend the use of a Bona Primer as a first coat.  A primer is more economical than a top coat, but apart from cost savings there are sound technical reasons to use a primer.  Bona Classic and Bona Intense are designed to ensure that the possibility of edge bonding is minimised and that the floor has an even look without discolouration or a patchy appearance.  if a whitewashed or white appearance is required then Bona White may be specified.  Having the same properties with regard to the other primers Bona White allows the floor colour to be altered without losing the benefits of a primer.

Both Classic and Intense have significant technical differences that make consideration of the particular installation very important.  For example, Intense is recommended to minimise the effects of tannin bleed on timber species such as Blackbutt and minimise the possibility of edge bonding.  On the other hand whilst Classic will similarly minimise the possibility of edge-bonding it is also the choice for floors where the aim is to keep the colour of the floor as light as possible, such as where 'blonde' timbers are used.  Bona Classic and Intense dry faster than top coats representing a significant time saving.  

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What about maintenance and floor care?

In addition to the finishes which are available Bona also have a full range of maintenance and floor care products suitable for commercial and lighter use areas.  We can assist in developing a complete specification for any contract you may be involved with including advice on preventative maintenance, the choice of finishes and helping to prepare an on-going floor care / renovation programme. 

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How important is design?

The design of a building and its floors can affect coatings and maintenance issues.  For instance, in a domestic property the fashion for open plan living brings difficulties in that there can be an issue in keeping a wet edge along a corridor when having to coat individual rooms off of this.  Similarly in living, dining, kitchen open plan living areas the scale and layout can prove problematic.  Having thresholds at doorways separates areas and allows individual areas to be coated more easily.  Similarly in commercial areas, whilst it is clear that some areas need to be maintained as a single large floor area, by trying to keep sections within some premises to perhaps 100 or 200 m² this allows commercial premises to continue to function and trade whilst sections of flooring are overcoated as part of normal maintenance operations. 

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What may be the effects of sunlight on the floor?

The ultraviolet spectrum within sunlight can affect any organic material including timber.  Any exposure to light will bring with it some change in colour to a floor irrespective of the use of a stain or finish and even if the surface is not in direct sunlight.  Lighter timbers, such as Blackbutt, tend to slightly darken when exposed whereas darker or redder timber species, like Jarrah, may become darker or if exposed to extreme direct sunlight can become lighter.  The use of water-based finishes can slow the changes seen but cannot prevent the process from occurring.  Bona finishes do not themselves darken or yellow over time, unlike solvent finishes, but they do not contain any UV blockers and where required consideration may need to be given to the use of UV resistant films on windows, etc.

All timbers, and cork, when exposed to very direct sunlight over an extended period of time are susceptible to ‘fading’ where the surface of the timber can lose most of its colour and become almost white or grey in appearance.  This is most noticeable with darker and red timbers but can also be clearly seen on lighter species and timber artificially coloured by heat treatment.  It is important therefore that this effect is acknowledged as having the potential for causing colour changes so that steps such as the use of UV blocking films and window dressings, e.g. blinds, curtains, etc. can be put into place.

If colour changes do occur sanding the floor to bare timber will remove the affected surface layer and allow the floor to be returned to its original colour.

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What is edge-bonding?
This is a potential problem where movement of the timber due to moisture content fluctuation can result in cracks developing in the floor.  It occurs where the boards are stuck together due to a finish penetrating into joints between boards.  Typically up to 10 or so boards are stuck together.  When they shrink rather than each joint between the boards opening up the shrinkage for the whole area is seen at a single joint, where the adhesive bond is weakest, and this may be over 10 mm.  In some cases the adhesive bonds at the joint are so strong that the timber itself breaks and a crack develops along the length of a board.  Water-based finishes have a lower tendency in general to give this type of effect and Bona have developed products where they specifically engineered the finishes to minimise edge bonding.  For this reason it is strongly recommended that a Bona Primer is used prior to application of Bona finishes.

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What is ‘tannin bleed’?

This is a discolouration that occurs with some timber species containing high amounts of tannin, especially Blackbutt.  After the second coat has dried the effect is seen as a green, blotchy or blurry look.  Sometimes the finished floor can still be acceptable, but often the floor needs to be sanded back to bare timber and coated again.  Always use Prime Intense when coating Blackbutt or other high tannin timber species. 

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