You can get ceiling mounted infrared heater it will easily heat that space.

Did you consider a Natural Gas Patio heater? Our covered deck section ceiling is 12' and I did not even consider a ceiling mount heating option however have an accessible gas line/outlet installed under the deck. which we can use for any gas appliance. We live in Blaine, WA

Pinebarron we opted for electric heaters but haven’t chosen a brand yet. For now the deck is being wired for two but we need to decide what two. Infrared is one of the choices but we are also considering bromic heaters. That said I’m going to the site today for a meeting so I can easily ask about the idea of gas options!

Now that's an idea; Bromic natural gas heaters. NG heaters will no doubt require a gas line installed and unless it is done as part of initial installation a retro install may possibly be an expensive option.

My husband is opposed to gas heaters. So we are sticking with electric. :)

:)