Yellowing Exteriors

The particular problem which we solved together will be familiar to everyone working with external woodwork.


Manufacturers of traditional hardwood windows and doors 


This longstanding client has been pursuing their main line, the installation of bespoke traditional hardwood windows and doors, for over 40 years. Their products are created by UK craftsmen in a 25,000 square foot in-house joinery.  

As with many of our exterior woodworker clients, they are firmly committed to the expansion of their business, so are always looking for ways to improve their processes. 


The particular problem which we solved together will be familiar to everyone working with external woodwork: the dreaded Yellowing Primer. This one’s so commonplace that many woodworkers believe it to be inevitable. Fortunately, our client rejects conventional wisdom! 

Primers yellowing can occur for several reasons, one being the oxidation of the alkyds or oils which form the basis of traditional primers. Organic substances of any kind tend to discolour when exposed to sunlight, so oil-based primers tend to yellow over time. 

But in this particular scenario, yellowing occurred because of the tannins in the wood leaking through. 


Our supplier, Zobel, has pioneered novel, water-based primers which don’t suffer from this problem. We were pretty sure that the ZowoTec product line would provide them with the non-yellowing finish they needed. 


After some positive initial trials, our client began using ZowoTec 385. At first, they used the Zobel products for base coats only, retaining their existing top coat supplier. But, having experienced the finish quality of the Zobel base coatings, they’re now using colours and clears from the ZowoTec range for top coats too.  

The new products provide an ultra-smooth, non-yellowing finish – and help our client to stand out in a competitive market.

To learn more about Zobel products from Redwood, give us a ring on 023 9223 3310 or email