Assuming they have been serviced regularly, most decks can be revived with just a deck cleaner. Start by filling in knots, chips and cracks with latex putty or the restoration product. Let it sit until it is firm. Next, apply the coating to the cover with the special roller (Photo.
You will need to reload the roller every few feet to get the proper coating thickness. Do not try to make the product go further by working back and forth so that it is diluted and loaded with air bubbles. Coat several boards at once (Photo. Some products will fill the gaps and others will fall and go to waste (get over it; it's part of the cost of labor).
Fill the holes along the way (Photo. If you prefer a smooth finish, level the coating immediately with a brush (Photo. Restoring a worn roof is a great project to tackle alone or with a partner, and returns a noticeable and satisfying aesthetic improvement. It requires a smaller budget than replacing a deck, but it provides a big payoff, especially if you're considering putting your house on the market.
If you don't have time, tools or equipment, or if you need structural repairs, don't hesitate to contact an expert roofing professional. But if the problem is only aesthetic and you are ready to tackle the project on your own, these steps will show you how to restore a worn cover.