Mystery meat.................no pictures, no nothing

What are their condition? Interested in refinishing or painting? Will a large rug solve anything and be appreciated over the winter?

Usaully a porch is not a living space so maybe check about how to meet code. How are heating this new living space for starters what finish is on the floors now ? Other than that we need pictures and info as to what you have got permits for. I have no idea where you live either .

This is in Florida on the bay and yes we will have permits to fully enclose the room with heating and cooling and insulation under the floor. These floors are cypress and have been there for 15 years exposed to the harsh salty environment. Usually they get cleaned in the spring with a bleach solution but we are not doing that this spring in anticipation of construction.

It's going to be an extension of indoor space, so either rip those floors to match what is inside, Or when done with construction, sand and refinish, and seal those as any other wood floor. It's becoming an HVAC/ conditioned space, right?

I'm surprised they lasted 15 years if routine sealing wasn't done......given they were exposed to all elements

It will have to be rebuilt as habitable space, to code, first. You are not keeping those boards as a finished floor unless you remove them, and then re lay them as a finished floor after all of the basic construction infrastructure underneath is done. Keeping ehat is there is never going to happen. You are talking about a full rebuild.

Yes, insulate and seal the floor from the underside. You say you want to do that, and that's probably one of the more difficult challenges to enclosing the porch. The wood looks nice, cypress is living up to its weather resistant reputation there. I'd wash it well before you start the sealing to allow one last big wet cleanup and dryout before you start. I see some green tinges on the wood that you probably want to address as much as you can while you can be messy about it. I feel kind of torn about treatment after that. It should be sealed, but it is rather pretty in it's current weathered state.

Thanks everyone for the suggestions. This will be a fully sealed, heated and cooled and insulated room with hurricane windows and doors. The interior of the house has wide planked pine floors with a cottage vibe. We will not be removing these floors as they are in great shape. After cleaning, deliberating whether to clear seal, stain and seal or paint. They do not have to match the interior since it will still look as if it’s a porch. Thanks again for your input. I will post some pics after complete.

You cannot do the needed infrastructure to build that as a house extension without removing those boards. That's not how making it meet building codes works. They have to come up. If you want to relay them as interior flooring, that's well after the fact of the build out.

It can be difficult to reconcile these as extension, give the new enclosed both a separate, and unified with interior feel. If you want the look of a sun room extension to living space, and plan to leave interior doors if there will be those, if the floor will be level with the current build, or not?? All these come into play.

You are leaving the interior floor alone, it is pine, so perhaps a nice tile beyond, even heated if that's a need, In Florida, even at the northern end - that may be ALL the heat you need -given heat rises.

You have mo interior photos, no dimension of the space - it looks "porch" In size. You may want to go out a bit further,

Not enough info to advise, and your question could use more context.

That cypress has such a nice weathering and grain to it, I think it would be a shame to paint over it. I would hesitate at a stain color too. But yes, sealing it would be for the best. I know cypress can weather up great outdoors, but once you enclose the room having it untreated can become an issue later on.