Question about footings and walls.

Hello, I have a concrete porch that has a roof over It. The roof spans between my house and my garage. The weight of the roof is solely supported by the house and garage walls.

What I would like to do is add on a small mud room/laundry room. The framed walls would span between the garage and the house, there would be a total of two walls.

These walls will not support anything structurally besides themselves.

Question is, can I build these partition walls directly on the concrete slab, or would I have to cut out concrete, dig and pour a footing for them?

If I need a footing, is there another way other than cutting and pouring a footing?

 

Underpinning. Excavate under the pad, pour a footing, place insulation against the excavated ground then form and pour a foundation to support the pad. Cutting the pad likely makes more sense in your situation.

If you don't want it to be cold out there you will need to add some source of heat.

 

Yeah, I think cutting a section of pad out and pouring a footing would be a bit easier than undermining.

As for heat, I'm going to run a supply off my hvac and put the register right in the rim joist facing out into the new room.

Im not going to start this project until next spring, just trying to get all my ducks in a row planning before I dive into it.

Im planning on putting tile down, I think I may insulate the slab then put tile over it, the porch is about 5" Lower than my house is, so it would hurt to raise it a bit.