If a water repellent were able to bead water long-term, it would most likely promote dry rot by starving the wood for the moisture it needs 
(a water repellent; were; able to bead water long-term) (a water repellent; to bead; water long-term) (it; would most likely promote; dry rot) (the moisture; needs; it)
a water repellent a water repellent it the moisture
were to bead would most likely promote needs
able to bead water long-term
water long-term
dry rot
it