Grey teak is sun/UV destroyed - the surface cells of the wood are broken down / destroyed.
Teak is now approaching $50/board ft.
Typical UV destroyed bare teak will erode at approx. 1/8" per ten years.
• Varnish is a continual PITA to apply, and reapply ad nauseum ... but nothing looks better if properly applied and then 'finished'.
• The 'modern' 2-part coatings can last up to 10 to 12 years with 'little' maintenance - super expensive but 'can' look close to varnish. example: Teak Oil vs Varnish vs Cetol
.... post #32.
• Teak oil, including 'resinated' (varnish + oil mixes) teak oils, will eventually turn 'dark' and need to be continuously stripped (1-2 yrs) ... can be 'glossier' than varnish if resinated and then hand-rubbed/polished.
• multi-oart layered systems: CPES + oil based varnish + urethan varnish + 2 part clear (Interlux perfection, etc.) eventually crack and do not stand up to water permeation 'through' the wood --- lifting and 'darks'.
(if pigmented) retards UV destruction but needs to be recoated every 4-6 months if exposed to 'green' water. Usually needs to be 'stripped' every 2 years. ~$90/gallon. example: look at the decks in Teak Oil vs Varnish vs Cetol
.... post #32