Hello, I am looking for the best fit for application on existing and well-weathered timber construction to /increase fire resisitatnce. It is for Graded buildings where the outlook of the structure must be preserved so I need sometthing less visible after the application. Can you please advise me which product wouild suit best to this requirements and what the preparation of the surface process would be? Kind regards, Kaloyan Markov 07989213916