Adding onto a stick built house using earth bags?

I need to add on to my current home which is a large double wide which is solidly attached to concrete footers via steel pipe. It doesn't settle.

My first question would be : are there any woes with building off of a wood structure using earth bags?

I also have an odd chunk of land with ground water at around 5 foot. I have juts over a foot of top soil, below that is sand and river rock. I'm fairly close to a flood area. I am not exactly sure how deep bedrock would be found.

I'm planing to build up a foot with bags then back fill and either lay a stone floor or possibly a compacted soil cement floor. It will be a heated floor. Then I would continue up with bags as walls. I do also have tires. A lot of them. But sand bags are so much easier to work with.

The room will be around 12'-18' x 60' with square corners if possible. The south wall would be 60', east and west walls 11' tall 12'-18' long with bags. The north wall is the existing house. There would be 2 bedrooms then the rest open as a living room area.

The roof will be steel framed with red iron. Sloped shed design with Metal roofing.

I would be replacing the skirting of the house with an earth bag pup wall. All concrete stucco.

Would I be wasting my time attempting this. I've built standard wood framed houses. This would be new territory for me. I'm more worried about integrating both building designs together without a lot of problems. This entire plan is due to the cost of building supplies. I have to build on in order to make more room for my kiddos.

There are lots of potential obstacles;
- settlement of the new walls
- causing detachment between buildings
- a test of the soil to take a building load is needed.
- stick frames are much lighter than earthbags.
- Is the soil ok for earth bags?
- Is time important?
- either dig a deep footing to  resistant surface or sink screw piles
- It seems your existing house has a similar system to spread the load.
- Hebel bricks are low weight.
- Can you shift a building / house to the site?
- can you collect and use second hand materials of any sort ?
- What climate are you in, it is important to take note of that.
- Do you need it that big, a 50 x 12 or 20 ft lounge is big.
- Would it ever flood? Because the existing foundations are best for that situation.?

If you have groundwater 5' below the surface (and potential flood issues), a moisture break below the walls and floor is essential. Earth bags would make fine wicks, and in case of a flood, keep the structure damp for maybe months. If you have tires on hand, I would use them for the first couple-few layers at least to isolate your floor from damp. An actual vapor barrier would also help.

Earth bag walls would be much heavier than your current structure, and demand significant footings. Do you have rock available for a rubble trench? Is there any slope to your building site? What is the climate and frost depth?