Elevated addition

[enginerd]

Thanks all. Oh yeah, we are making sure contractor pulls all required permits. "Bigfoot" footings are to be below the frostline (min 4 ft), and the insulation in ceiling, floor and walls meets or exceeds the EnergyStar guidelines for my zone. That business Enginerd mentioned about uplift in strong winds, well that's one I'll have to ask about for sure! Might have to box in underneath.

If you go to the Bigfoot website, they have some test data for uplift. So, depending on the number of posts and the sizes, the design might be ok, or it could be a simple change such as an extra post or a larger Bigfoot.

 

[meierlde]

Thanks all. Oh yeah, we are making sure contractor pulls all required permits. "Bigfoot" footings are to be below the frostline (min 4 ft), and the insulation in ceiling, floor and walls meets or exceeds the EnergyStar guidelines for my zone. That business Enginerd mentioned about uplift in strong winds, well that's one I'll have to ask about for sure! Might have to box in underneath.

In addition boxing in the underarea would increase the temp under the room at least a little bit, as it would be then more like a crawl space, thus making the heating requirements for the room above a bit less (at least no wind to take heat away from the outside of the insulation, unless you were planning to put sheathing on the bottom of the joists after insulating.

 

[NW-Bound]

Did you get the good insulation and adequate ductwork, and did it work, or did you wind up thinking it was a mistake to build it in the first place?

The insulation of the room addition is better than that of the existing structure. Else, the temperature swing would be a lot worse. The central heat pump is a 5-ton unit, and should be able to handle the 400-sq.ft. addition. The problem is the airflow to the area is too weak due to its distance from the air handler.

For expedience, we solve the problem with a supplemental portable electric heater when needed. Thought to myself that the airflow could be enhanced with a inline duct blower, but I still have not added it after 25 years.

By the way, the contractor used engineered I-joists rather than the typical 2x12 joists (the addition is 14' x 28'). See photo. The floor feels solid, and superior to that of the existing structure. The joists span the 14' width. One 28' side is supported by the existing wall. The other 28' side is supported by a long laminated beam resting on 3 posts. The posts are resting on concrete footings built to the local code. The walls are built with 2x6. The roof is tiled to match the existing structure.

I have not had any structural problem after 25 years.

 

[Tree-dweller]

The insulation of the room addition is better than that of the existing structure. Else, the temperature swing would be a lot worse. The central heat pump is a 5-ton unit, and should be able to handle the 400-sq.ft. addition. The problem is the airflow to the area is too weak due to its distance from the air handler.

For expedience, we solve the problem with a supplemental portable electric heater when needed. Thought to myself that the airflow could be enhanced with a inline duct blower, but I still have not added it after 25 years.

By the way, the contractor used engineered I-joists rather than the typical 2x12 joists (the addition is 14' x 28'). See photo. The floor feels solid, and superior to that of the existing structure. The joists span the 14' width. One 28' side is supported by the existing wall. The other 28' side is supported by a long laminated beam resting on 3 posts. The posts are resting on concrete footings built to the local code. The walls are built with 2x6. The roof is tiled to match the existing structure.

I have not had any structural problem after 25 years.

Good info. Thanks