Connecting Driveway to Foundation with Rebar
Connecting Driveway to Foundation with Rebar
(OP)
I've seen this done a lot while working for a general contractor, however recently I'm told it is a bad idea and frost could destroy the foundation stem wall so its better not to connect the driveway slab to the foundation wall. Detail shown below. I've also seen a lot of concrete "experts" promote connecting in this manner or with dowels. Thoughts and comments appreciated.








RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
http://www.standard.net/stories/2014/02/26/proper-installation-key-driveway-lasts-longer
http://www.douglasfoundationrepair.com/the-anatomy-of-a-driveway-pour-austin-concrete-raising-or-mudjacking/
RE: Connecting Driveway to Foundation with Rebar
Be wary of any recommendations coming from someone who thinks this is a good idea.
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
setting the slab on a ledge will only crack it when it settles, it is not a structural slab. same with dowels, it is a thin, un-reinforced or only lightly reinforced slab, it will settle or heave and it will crack.
just use care in the earthwork and good compaction, provide good drainage and slopes so so water does not run towards the foundation wall, install good expansion joint material in the gap to fill it and seal it properly and then maintain the seal to keep water out. nothing else is needed.
RE: Connecting Driveway to Foundation with Rebar
First link is for new repairs to existing homes; Here I think there could be some merit in the detail, but I would still think a better result could be obtained with less problem-prone replacement details.
Second link is specific to southern climates, and frankly a great deal of details can work through tremendous abuse thanks to the additional load paths, reserve capacity, etc inherent in residential construction. That said, we are expected to do better as Professionals.
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
Do we just go with what cvg commented?
"just use care in the earthwork and good compaction, provide good drainage and slopes so so water does not run towards the foundation wall, install good expansion joint material in the gap to fill it and seal it properly and then maintain the seal to keep water out. nothing else is needed."
I may be overthinking this.
RE: Connecting Driveway to Foundation with Rebar
the driveway slab is separate, not connected and has its own design. dependant on site soil, traffic and climate conditions you may need 4 inches gravel base or 12 inches gravel base. you might need 4 inch thick un-reinforced, in other areas perhaps thicker or reinforced is recommended. your subgrade may be expansive or frost susceptible in which case either you plan for the heave and settlement movement or try to prevent it
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
Then call out a 4" min. gravel base as required. I think we can all agree I should have at least 4" of gravel, possibly more.
Change the backfill note to "95% compacted granular backfill",
and then get rid of that bent out rebar.
RE: Connecting Driveway to Foundation with Rebar
Mike McCann
MMC Engineering
RE: Connecting Driveway to Foundation with Rebar
Mike McCann
MMC Engineering
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
1. Dowel with expansion joint (for zero frost environments)
2. Concrete ledge with expansion joint and breakaway joint for vertical uplift due to frost heave.
3. Replace all of the soil down to the footer/frost line with gravel, crushed rock etc... and slope it out gradually to about 10 ft in front of garage (mostly costly option)
4. Leave as is with an expansion joint and remove bent out rebar and detail it out so driveway slab is shown as "by others". The theory is that driveways eventually need replacing anyhow and if special considerations are needed then the owner and the contractor can address them in the field.
RE: Connecting Driveway to Foundation with Rebar
dowels or rebar are unnecesary
a ledge will promote cracking
option 3 is ok but expensive
and why do you insist that driveway is by others?
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
Option 4, but do not say "by others"?
RE: Connecting Driveway to Foundation with Rebar
Your two, three and four are not bad; They are simply options. Where and when to apply them will come with experience, but each can be adapted. The fun part is that most of the time the RIGHT solution is the safe, effective and economical choice.
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
RE: Connecting Driveway to Foundation with Rebar
AND DON'T DOWEL GARAGE TO DRIVEWAY.... EVER! :)
And yes, 8" turndown is a good idea, not sure why the need for a 40# felt bond breaker though.
RE: Connecting Driveway to Foundation with Rebar