The job of insulating the floor is easier if there is room to crawl underneath but if there isn t it can still be done.
Screened porch floor insulation.
If it is above grade winter drafts will make the room too cold to use no matter how well the walls and ceiling are insulated.
If your porch is screened the first step will be either to add glass all around or to replace the screen with standard glass panels.
Start with the basics thermally efficient glazed doors and windows are essential to keeping the cold out.
Basically you should be thinking about insulating the roof floor and walls to ensure the maximum benefit.
This can be stapled up between the floor joists.
Use a vapor barrier to keep your floor above free from condensation caused by the new insulated area.
Insulating the floor is an important step in porch conversion.
If your floor joist are 16 inches on center you can easily install bat insulation that is assuming you can get to the underside.
Or you can finish off the underside with vinyl soffit siding.
Adding insulation batting to the walls and floor of your three season porch can extend its usefulness during cold weather.
Enclosed but uninsulated sitting areas are known as three season porches but if you live in a northern state cold weather can reduce that to two or even one and a half seasons.
Do it yourself video on how to insulate the exposed floor over an unheated area using roxul comfortbatt r28 canada or r30 usa and roxul comfortboard is i.