Joining new slab to exisitig

[randyandrewsberg]

The building has a monolithic slab & footer in one continuous pour, and is traditional stick framing. The car port addition was an afterthought during construction and put up using the utility poles set a few feet into the dirt to support the far end, but the beams that run to the poles are tied into the rest of the building and it has one continuous roof. I would like to have a cement pad poured in the area under the car port to make it more useful. I want it to be level with the existing garage floor, and I think I want to do an identical slab & footer in one continuous pour just like the rest of the building to leave the option to more easily enclose the space in the future if I desire. I would also be removing the utility poles and supporting the roof with a 6x6 post bracketed to the slab or something more conventional than utility poles. Assuming everything I've said to this point makes sense, here are the questions I have for garage journal:

1. Do I want the two slabs tied together or independent of one another?
2. Can I pour right next to the existing slab or should I leave a gap? If so, how large?
3. How would you take the weight off the utility poles & support the roof so you could remove them to dig the footer, and where would you put the bracing pushing against each other or against the existing building?

 

[dave*99]

Support the roof as shown

 

[dave*99]

I would drill horizontally into the old slab at the edge.
Insert rebar with epoxy.
Pour the new floor abutting the old floor and encapsulating the rebar stubs.
This keeps the 2 slabs flush

 

[ddawg16]

1. Do I want the two slabs tied together or independent of one another?
2. Can I pour right next to the existing slab or should I leave a gap? If so, how large?
3. How would you take the weight off the utility poles & support the roof so you could remove them to dig the footer, and where would you put the bracing pushing against each other or against the existing building?

1&2 - Pour next to it. To keep them tied together....drill holes about every 8-12" large enough for a #4 chunk of rebar. You want the holes at least 6" deep or more. This will take card of vert movement....basically, lock them both at the same level. If you want to insure they don't separate, epoxy the rebar in.

3. Do like Dave suggested. Or, get a big *** beam that is about 4' longer than the gable on each side....support that with posts....this would give a nice clear span to work with.

I would also suggest digging your footing down far enough to expose the footing of your existing slab...do some more rebar pinning there. That would lock you in pretty good.

 

[DJL1967]

I would drill horizontally into the old slab at the edge.
Insert rebar with epoxy.
Pour the new floor abutting the old floor and encapsulating the rebar stubs.
This keeps the 2 slabs flush

I did it this way to extend my garage 4'. I spaced rebar every 12" drilled 6" deep holes into existing slab and applied epoxy. Tied rebar throughout the pad in 12x12 squares. No cracks or movement in 2 cold winters.