Monolith slab inspection

[Jetboy]

I'm building a garage.

It's been difficult at times. I've finished the dig for the slab. It's a 24'x24' detached garage. The thickened footer required is 30" below grade and 6" above and 24" wide. Seems insanely big to me. I'm pretty sure my house doesn't have a 36x24" footer all around.

Anyway, I've dug a big trench with a mini ex and put up form boards around the top anchored with posts.

I laid plastic and put my 3 runs of 1/2" bar down and tied the corners etc.

I'm only about 26" deep in some spots. Possible even less in others, where it should be 30" from grade.

Otherwise I feel like I'm in pretty good shape for pouring. I need to get inspected before I pour.

Any tips on what the inspectors usually look for here? I feel like I'm building footers strong enough to build bridges with, but I've never done this before so I'm a bit apprehensive about the inspections and what they are looking for.

 

[splitshot]

Depends on the inspector. Probably need an ufer for a ground also.

 

[KLF]

In my experience it totally depends on your town/city and the person doing the inspection.

The reason for the big footing is because of the monolithic slab. Normally slabs "float" inside the stub walls/footings. You need to make sure the wall loads are transferred to the slab, and there are no excessive settlements at the walls, or you will have a bunch of cracks.

 

[Jetboy]

That looks pretty much like what I've got. It seems like 20+ish yds of concrete for a two car garage is a lot. Especially since the previous one was a 4" slab on dirt with no footer and it lasted 60 years with some cracks, but nothing terrible.

 

[Jetboy]

Update:

Inspector came out. Looked at it. Said "that's more rebar than most commercial buildings I inspect. Can I look at your plans?" Looks at plans. "This seems really overkill, did you draw this and have an engineer stamp it?" "Nope that's what the county engineer wanted" "Huh... OK" Signs off and I'm clear to proceed.

 

[KLF]

Nice.

I got the same reaction when I built the decks on the last duplex I built for Habitat. I followed the codes for spacing, bolts, tension ties, ledgers, etc. The inspector said he's never seen a deck built like that. I should have known when I had to special order some of the brackets.

 

[Cookiemonster]

Looks like you've got it squared away. Thought Id throw these ones out there for fun, just so you can see the rebar. These are several months old as later pics have subsequent walls and columns with columns having 3" rebar threaded for plates.

 

[Jetboy]

That's a lot of steel in that concrete. It looks like it could be really difficult to get the concrete to fill without voids.

 

[splitshot]

That is what vibrators are for, Holly Cow, post pics of the load. please.

 

[bkfj40]

vibrators are over rated...or atleast this is what the contractor I am dealing with on this project to support a 40' tall silo and plans for an 80' in the future. I came back to this headache after vacation....

 

[Titan]

You don't give your location,but obviously where you are will play a very important role in design, here at the beach overkill is mandatory, further west 24 x 36 footer isn't needed due to substrate. considering the trouble and expense you've gone to, prior to pour have some plans for expansion joints,be it wood inlays or foam, also keep your slab wet for a few days.slower cure time helps with cracks. it will take two trucks to fill,so make sure there both on site prior to pour, check slump of crete, get a small container, cut bottom out, pour sample into cylinder lift off cylinder and see how far concrete "slumps" you don't want more than a 5" puddle,it will mean crete is too wet..cracks.are you using sill bolts to secure bottom plate? plan out location's,and we prewrap threads with saran wrap to keep crete off threads..steel rake to agitate crete in footers,insures even distribution of pour good luck Amigo.

 

[Jetboy]

Thanks titan. I hired a concrete crew to do the pour and finish. The reality around here is that they can buy concrete about $30/yd cheaper than me and the guys I contracted with at least passed some of the savings to me, so the labor is more or less free when I priced out 30yds at my price vs their quote.

I was on site and generally I'm really happy with the work they did. I got the delivery slips directly from the concrete trucks to verify the concrete mix we agreed on and they weren't playing any games that I could tell. I cut expansion joints about 6 hrs after the pour and so far I've seen one small hairline crack outside my joints. I did sink the blade as far as it would go about a foot in from the edges on each expansion cut. There are no visible cracks in the footer area so either it broke along the cuts or hasn't cracked yet. It's been 3 weeks now, we'll see how thing go from here. I've driven a tracked skid steer over it about 50 times without issue to haul a bunch of dirt across it that I can't get to once the walls are up.

My only beef with the concrete guys was that they didn't put the anchor bolts in soon enough. I've notices some of them are not entirely encapsulated - ie there are voids down the shaft of the bolt that probably should be filled entirely by concrete. They are plenty strong when I put a nut on and tighten it on the sill plate. The problem I can see is water eventually getting in there, then rusting out the bolts over time.

 

[Titan]

its to late now, but Simpson makes crete epoxy,2 part that uses a caulking gun, reinforces area's, and depending on area, water seeping into voids, freezing ..furthering cracking can be an issue. sounds like a good pour..now all you need to do is pour some 10w40 on the new slab..it has to be done..and if you do it,your less likely to get pissed when a stain eventually does show up...