Comparing three leading coating options to determine the most durable and cost-effective for internal wood finishing...

High-quality water-based wood coatings offer an excellent finish and great level of durability – due to these characteristics and the environmentally friendly aspects, these systems are continually growing in popularity.

The overall cost per litre/kg for water-based coatings is viewed as being slightly more expensive when compared to its solvent alternatives,  due to the raw materials and resins used in production. This can be especially true if there are tough durability requirements – the resins required to provide accreditations such as FIRA Gold have to be very high-quality and that comes at a cost

However, despite being towards the top of the cost range in the market, water-based coatings often prove 'value for money' when the below factors are taken into consideration;

• Reduction/removal of any activators/hardeners/curing agents

• Thinners, gunwash, solvent cleaner all replaced with tap water

• Single pack technology allows for huge savings in both paint mixing time, as well as virtually removing product wastage as you no longer have a pot-life to work with

• Insurance premiums can often be reduced with water-base coatings on site, due to it being less hazardous and flammable

• Waste removal costs drop hugely as permits can allow for the safe disposal of material down the drain

Once all factors are included in the equation, water-based wood coatings are normally a strong contender for being a cost-effective solution for internal wood coatings.

2-pack polyurethane products typically sit towards the upper middle of the cost range  - more expensive than acid catalysts (AC) but lower cost than water-based wood coatings (based on the per litre cost). The raw materials used are often cheaper than water-based, but due to the chemical properties of polyurethane, very high durability performance can be achieved. 

However, it is very important to always consider polyurethane costs as a “mixed” cost including the hardener, as this can be significantly more expensive than the paint itself and is often used in ratios as high as 2:1. Due to this hardener requirement, plus the need for dilution thinners, solvent cleaners etc, a polyurethane system would typically be viewed at the higher range of the spectrum.

Another important consideration is the additional cost of safely using these materials – in addition to being solvent-based, the hardener contains isocyanate and therefore a high standard of fume containment/extraction and applicator respiratory equipment is required.

When compared to water-based, as covered above there are also the additional costs of disposal, insurance and wastage due to mixed paint curing in the can.

Polyurethane can still be a cost-effective option, but normally only where there is a requirement for high durability and/or high -gloss finishes, and where the health and safety hazards/costs are not considered to be a major issue e.g. if the overall volume used is low.

If we just compared all 3 coating types based on their cost per litre, acid catalyst would be a clear winner, as it has been the cheapest coating option for internal wood finishing for some time.

Although an acid catalyst is a 2-pack material similar to polyurethane, it typically only requires a mixing ratio of 10:1 with a much cheaper catalyst, and therefore that doesn’t impact the overall mixed price significantly.

The cost of raw materials required to make this product type is considerably cheaper than both water-based and polyurethane coatings. However, when compared to water-based wood coatings, it shares many of the same disadvantages as polyurethane, with solvent, mixing and disposal costs.

Acid catalyst products do also carry a health risk as most catalysts contain formaldehyde which is a carcinogen, therefore high levels of extraction/ventilation and respiratory equipment are required.

They do have the advantage of excellent chemical resistance, so they can be a great solution if cost is the over-riding consideration for you.