How are people out there handling 3 season rooms. By that I mean a room with out heat. It could be an enclosed porch or deck. It might have have have windows or just screens. It could be a premanufactured conservatory kit. Do you install receptacles using the 6'-12' rule in the NEC?
You're describing a common sort of "creep" in building design.
The 'creep' occurs when a porch with a simple handrail first gets the spaces under the rails closed off .... then screens put up all around .... then glazing added. As this takes place, the porch begins to be used more ... from summer BBQ's, to a play area for the youngsters, to overflow seating for holiday meals or sheltered 'outside' smoking, to suddenly being used as a full-time, year-round room.
To a certain extent, the same issues can arise in mudrooms.
I think the key is the term 'habitable.' Such an enclosed area in the front of the house is unlikely to ever be a proper room - not with entry traffic constantly passing through. When the same happens to a patio in the rear, or a balcony, the picture might change.
That still leaves the matter of enforcement. With such an incremental series of changes, I don't see where permits are ever likely to be requested.
In a similar manner, I suspect that very few basement remodels are aver inspected. I think we have to recognize the limits of inspections, and accept that this sort of thing simply can't be regulated.
Otherwise ... if asked for an honest opinion, I'd look at the specific layout, and try to imagine it's possible uses. Even if they're calling it an office,' for example, circumstances might lead me to consider it as a bedroom.
When I went through permitting they told me they will go for the highest usage level they can get (probably for the tax man). I replaced a "finished enclosed porch" with a room on the same footprint and will have the same use. They still said it was going to be permitted as "Bas" (regular habitable space). I had to show egress routes just like a bedroom but they did give me a break on <no> AFCIs. In real life I have to live there so I exceeded 210 on lighting and receptacle outlets but they did give me a handout that said I needed to meet it. My electrical plan was the only thing that went through without a hitch. We went round and round for 6 weeks on structural engineering.
At another site, I am ALWAYS confronted with folks wo seem to delight in 'being clever.' Like the basement remodel, where every room was designated for something besides 'sleeping;' after all, those egress windows are a lot of work!
Yet, I bet when the house is placed on the market, it will include those rooms in the count of bedrooms- thus upping the price considerably.
Indeed, if those folks are to be considered the norm, then it seems a lot of folks consider it a sport to 'game' the system. In my work, I have very little patience with such nonsense; either they come clean on their true intended use, or they will not be happy with the result.
OK, a "sunroom" is mentioned in 210.52, and I have seen sunrooms with all the outlets including heat and AC in them. So they can be used all year round. However what about those "porches" that can not be used in the winter? As Reno stated, these kinds of rooms, seem to creep from not being used all the time, to rooms that can be used. As Reno also stated, maybe the key word here is "Habitable". If the room is habitable at the time of inspection, then it should meet the requirements of 210.52. If the room is not habitable at time of inspection, then 210.52 doesn't count.
Harold: Yes, I agree with what you say. When I'm there a 'porch' is a 'porch' What happens to an 'area' after the inspections is between the HO and a 'higher being'....until it becomes time for a CCO inspection. Our CCO guy is pretty good with finding 'non-permitted' projects. (NOTE: I said 'pretty good'!)
I think we are talking about a few different things. A screenroom is more of a deck with screens and a roof. They have wood planks for flooring with gaps to let water out. Maybe they will have a screen under the planks to keep the bugs out. They might not have any finished walls or cielings or some sort of sidding / paneling on the inside. Sometimes the wall is about 2" thick plus the sidding. Many times the structural members are exposed. Some enclosed decks are the same but have more windows. I seen a mix of windows and screens. Sometimes they are not too different then a gazebo. The doors outside are a screen door. The door into the house is a exterior door. The room sits on posts set on cement piers. IMO these are not living space.
A finished sunroom has finished flooring, insulation, drywall, and maybe HVAC. They have at least a 2x4 wall and many times the cieling joists are taller to acomidate the required insulation. Sometimes they are wide open to the rest of the house. The doors outside are exterior or patio doors. The ones I seen always had full foundations on a slab, crawel, or basement. IMO this is a living space.
I might be possible to build one of those screened in porches with a roof attached to the house in Florida but Lee County sure was not making it sound possible to me. They wanted engineering for wind code compliance for anything I wanted to build and hanging that big a roof out there without wind code walls and windows seemed to be an impossible obstacle. I guess all those "cabanas" and car ports scattered around the neighborhood has tightened up the rules. By the time I got out of engineering I ended up with BAS zoning. For the purposes of 210.52 it was not really important to me tho. My thatched roof tiki bar out by the pool meets the 6 foot rule.
Up here we have 'sunrooms' ranging from what active described above to the 'conservatories' that rival a lot of family rooms and living rooms. It slowed down in the last couple of months, but I had plans in the office today for a fairly 'large' one, two Sanyo type split system HVAC units, fireplace, a8 recept; 22 lights, 3 fans, and 8KW elec heat.