NJ code help for detached garage nightmare

[JerseyJohn]

I am in NJ and I hope people here could help me get some clarity on a bad situation. I am a homeowner not in the trades as will soon become obvious from my post and lack of understanding.

We contracted with a builder for a 14x24 prefab garage installed on a block foundation at frost depth. Plans were submitted for a monolithic pour with 12 inches of trench footers. (I didn’t understand the difference or any of this really at the time.) The Building Inspector called for the mono slab to be at frost depth and reinforced with rebar. The plans showed the slab to be 8 inches above finished grade.

Question 1: What depth by code does a mono pour need to be for a detached building in NJ?

They got a footing inspection, which they passed, but built the forms out of 2x8s, not filled to the top and placed on the grass about 3 to 5 inches outside the trench. The finished result is a slab that is 4 inches off grade in the front and 7ish in the rear. The slab also turns at a near right angle where the forms were placed on the grass and then goes in the 3 to 5 inches to the trench and then down. Because of this all 4 corners are unsupported. Since they covered all this up by piling dirt against the foundation, I had no idea that this had happened until later. They did not get any further inspections and placed the prefab garage on top.
Q2: Is a backfill inspection required in the case of a monolithic slab?
The city failed the building for height and incorrect foundation shape The builder says the shape of the foundation problem is only cosmetic and want to put some concrete around the foundation to fill the voids and told us that we should grade down around the garage and get some French drains and gutters (they did not offer to pay for these.)
Needless to say this is a giant mess and yes, I know I should have been more informed. Lesson learned.
Q3: From this story are there any other code issues I should investigate?
Thanks for any help understanding the relevant code.

 

[e hilton]

Hope you have not paid in full.
How did it fail height? By how much? The height should have been on the plans, was the slab and foundation too high?
Does the builder have a proper license?

 

[bill1952]

Your post is a little confusing. I think you ended up with or should have a monolithic slab with turned down (or thickened) edge like the upper left detail. (Add rebar in a seismically active zone.)


Since under 400 sf, bottom of turndown should be a minimum of 12" below grade. All of the grass and organic material under slab as should have been removed and a compacted gravel base put in place.

What is too high or too low that failed? "Wrong shape" is hard to understand but I'm thinking the slab overhangs the thickened edge, unlike the diagram in the code book?

I think you have a less than capable contractor and hope you have held back some payment. If the building department won't help with suggestions - and they usually have no legal obligation to - you probably need some on site help of an architect or engineer or a competent builder. Too many posibilities to guess what comes after that, but lawyer is one.

 

[JerseyJohn]

Your post is a little confusing. I think you ended up with or should have a monolithic slab with turned down (or thickened) edge like the upper left detail. (Add rebar in a seismically active zone.)
View attachment 10554

Since under 400 sf, bottom of turndown should be a minimum of 12" below grade. All of the grass and organic material under slab as should have been removed and a compacted gravel base put in place.

What is too high or too low that failed? "Wrong shape" is hard to understand but I'm thinking the slab overhangs the thickened edge, unlike the diagram in the code book?

I think you have a less than capable contractor and hope you have held back some payment. If the building department won't help with suggestions - and they usually have no legal obligation to - you probably need some on site help of an architect or engineer or a competent builder. Too many posibilities to guess what comes after that, but lawyer is one.

https://imgur.com/a/2qOALGI

Thanks for the help.
Here are some pictures.

You can see the way the forms were made. The unsupported corners. The 3 to 5 inch indent around the perimeter due to form construction. The 2x8 with a chalk line on it of where they would pour to and how the top of the slab is not 8 inches off grade (.5 of the 2x8).

They never got this slab inspected before placing the building on it. My understanding is that a backfill inspection is required. I am wondering about the case of a monolithic slab.

The turned down edge goes down below the frost line. That was required by the town.

Thanks for all and any help. I am trying to figure out in what ways they made mistakes according to code and general practice because they contend there is nothing wrong with the job other than aesthetics--even despite the town failing it.

 

[ICE]

Well then, I am still not sure what happened. Perhaps you can produce a drawing with dimensions. Were pictures taken? If you can provide enough information, forum members will be able to offer an opinion.

Was the footing and slab poured at the same time? That is the definition of a monolithic pour. If the inspector required a mono pour and approved the form-work hopefully there isn't a structural problem.

Understand that the drawings found in the code book are not the only possibilities. The thickened slab for example, that isn't always done. 90° dowels are common. So show us what you have.

I don't know what code you are under or what seismic zone or wind category apply so I'll not have much to say but East Coast members are thick here. Oh and by thick I am not implying that they are, well you know, "thick".

 

[JerseyJohn]

Okay I wrote some dimensions here.
I hope that helps.

 

[ICE]

Was the footing and slab poured at the same time? That is the definition of a monolithic pour. If the inspector required a mono pour and approved the form-work hopefully there isn't a structural problem.

I see it now. If what you are showing happened that way....that's a mistake that I've not seen before now. There must be several inches of the anchor bolts showing.

You're lucky that the garage was pre-manufactured.

 

[bill1952]

I think the undercut - the slab being full depth or at least to 12" below grade - under load bearing walls is deficient. I'm a little amazed anyone would do that and say it's ok.

I believe the model code requires the wood wall be a minimum 6" above grade all around, though personally I prefer at least 8-10, and my recently completed garage is 16" or more. I'm not sure if NJ code is amended to 8" or department's/inspector's personal preference.

I hope you didn't pay in full untill after inspection and inspectors should be telling builder it's not acceptable.

I know too little about rest of building to offer solutions but at the least, I think the undercut needs to be filled in with concrete with some rebar pins connecting existing and infill. Indpector to determine how deep - hopefully not to bottom of footing.

Separating building from grade by 8" depends on too many unknowns.

It is a mess. I wondered if builder was a lot less expensive than others.

 

[ICE]

I think the undercut needs to be filled in with concrete with some rebar pins connecting existing and infill. Inspector to determine how deep - hopefully not to bottom of footing.

Probably not the best advice. First of all he indicated that the inspector approved the form-work. Secondly an inspector should not design the fix. Put the contractor on the hook to submit an engineered fix to the building dept. for approval.

 

[JerseyJohn]

Okay I wrote some dimensions here.
I hope that helps.

I think the undercut - the slab being full depth or at least to 12" below grade - under load bearing walls is deficient. I'm a little amazed anyone would do that and say it's ok.

I believe the model code requires the wood wall be a minimum 6" above grade all around, though personally I prefer at least 8-10, and my recently completed garage is 16" or more. I'm not sure if NJ code is amended to 8" or department's/inspector's personal preference.

I hope you didn't pay in full untill after inspection and inspectors should be telling builder it's not acceptable.

I know too little about rest of building to offer solutions but at the least, I think the undercut needs to be filled in with concrete with some rebar pins connecting existing and infill. Indpector to determine how deep - hopefully not to bottom of footing.

Separating building from grade by 8" depends on too many unknowns.

It is a mess. I wondered if builder was a lot less expensive than others.

Thanks to you all for taking the time to write this.

Let's just say that as a new homeowner I learned some valuable lessons and that as they say cheap is expensive.

Where do I find if NJ code is 6 or 8 inches?

Your pinning fix was one suggestion from the builder but will not deal with the height problem or give us the block foundation we contracted for. I am assuming this was a much cheaper way to do things.

Probably not the best advice. First of all he indicated that the inspector approved the form-work. Secondly an inspector should not design the fix. Put the contractor on the hook to submit an engineered fix to the building dept. for approval.

The building inspector checked that the footing trench was reinforced with wire. The form boards were at least partially down when that happened so I don't think the inspector even looked at them. But if he did, is the contractor still on the hook to make it to code even if an inspector misses something?

Also, did they need a backfill (or some other) inspection before placing the building? Because I was thinking if they had gotten one, the inspector would never have let them place a building on this

And yes, the bottoms of the anchor bolts are exposed.

 

[ICE]

And yes, the bottoms of the anchor bolts are exposed.

Sorry...no disrespect meant...LOL

I don't think I would have anything to do with the players that resulted in this. Not the contractor, inspector or any of the workmen.

 

[ICE]

is the contractor still on the hook to make it to code even if an inspector misses something?

Yes. It is never too late to start over.

 

[bill1952]

Put the contractor on the hook to submit an engineered fix to the building dept. for approval.

Agree. But won't happen unless you have enough money held back from contractor.

I'm gathering garage is "complete"? A course of blocks and shorter walls could have solved it. Hard now because lifting building - not that hard by itself - screws up doors.

If the contractor is not going to do anything, you or a new contractor - tough to find for a new multi-million dollar house let alone remedial garage work - needs to find out exactly what the building department will accept. You may need to beg for mercy. I've been fortunate that any building departments I've dealt with have been very helpful, including suggestions, and one electrical inspector who picked up tools when I was struggling with a new 200 amp service. I realize not all, maybe darn few, are that helpful.

 

[e hilton]

You didn’t say if the contractor has a state license. If yes, many states have a relief fund that you can apply to for possible restitution. If nothing else, report him for poor work.

You could get an engineer involved to give a sketch on how to solve the unsupported slab. Basically digging deeper to undisturbed soil, form and pour with proper procedures for getting the new concrete up tight against the existing.

 

[JerseyJohn]

Thanks to you all for the comments and suggestions.

What about the inspections required for a monolithic slab? I feel like they should have had it inspected before placing a building on it.

What's the price difference between block and a mono pour? Did he not give me the block to save money?

 

[bill1952]

Block vs poured - not so much cost but more likely skill your contractor doesn't have and time.

Separate poured footing, block stem wall, and then second pour for slab - more expensive if contracting, especially since they didn't really form the poured stem wall.

Were there drawn plans? A written contract?

 

[ICE]

What about the inspections required for a monolithic slab?

Footing and slab is one inspection. Once the work passes inspection, the concrete is placed. The next inspection is the framing…or in the case of a manufactured building, anchorage and the joining of the sections. There is no inspection of the slab prior to erecting the building or the minor backfilling around the footing.

You have mentioned “prefab garage” which doesn’t rule out a kit type with walls built and trusses delivered in a pile. If that’s the case, the framing inspection would be more involved than a manufactured building.

As it stands, the fix will take longer than the first attempt and cost close to the same. It’s not going to be a simple five inch ribbon. There will be a trench next to the existing that is wide enough to accommodate a drill motor. All-thread rod or 14” J-bolts need to take the place of the existing anchor bolts.

 

[JerseyJohn]

Footing and slab is one inspection. Once the work passes inspection, the concrete is placed. The next inspection is the framing…or in the case of a manufactured building, anchorage and the joining of the sections. There is no inspection of the slab prior to erecting the building or the minor backfilling around the footing.

You have mentioned “prefab garage” which doesn’t rule out a kit type with walls built and trusses delivered in a pile. If that’s the case, the framing inspection would be more involved than a manufactured building.

As it stands, the fix will take longer than the first attempt and cost close to the same. It’s not going to be a simple five inch ribbon. There will be a trench next to the existing that is wide enough to accommodate a drill motor. All-thread rod or 14” J-bolts need to take the place of the existing anchor bolts.

Good info. Thanks.

We have a contract. The builder is registered. The contract says we were to receive a block foundation at frost depth. We got this monolithic mess instead. I didn't understand the difference. So yes, I feel stupid and scammed. Believe me. Lesson learned.

 

[JerseyJohn]

Block vs poured - not so much cost but more likely skill your contractor doesn't have and time.

Separate poured footing, block stem wall, and then second pour for slab - more expensive if contracting, especially since they didn't really form the poured stem wall.

Were there drawn plans? A written contract?

This was done all in one pour. It's all one big piece of concrete. I figure that has to be cheaper than pouring footings, putting in the block, and then pouring the slab. The labor at least is much greater than this one day job they did here.

 

[e hilton]

Monolithic slab and footings is not necessarily bad. Most houses in south texas (austin, san antonio) are built that way. The trick is to design and build per the planss. You could have got a quality foundation for your garage … except the contractor wasn’t skilled.

 

[bill1952]

In my experience, inspections vary. Here, footing (form and rebar) was required, and completed foundation before framing started. After that, just completion, since framing is exposed.

6 vs 8 inches - ask inspector to point that out. That could be tougher fix than undercut.

Both fixes require skilled labor. Finding that in these times may be most difficult part.

Start calling masonry contractors in your area. You want them to design a solution acceptable to building department and do the work.

 

[JerseyJohn]

Thanks.

If anyone sees any more code issues, please let me know.

 

[ICE]

6 vs 8 inches - ask inspector to point that out.

That bit of code will say "exposed ground". A concrete apron solves that problem.

R317.1 Location required. Protection of wood and wood-based products from decay shall be provided in the following locations by the use of naturally durable wood or wood that is preservative-treated in accordance with AWPA U1.

1. *******
2. Wood framing members that rest on concrete or masonry exterior foundation walls and are less than 8 inches from the exposed ground.

 

[Mr. Inspector]

The slab is required to slope towards the vehicle door or a drain per IRC. I don't know if the NJ code requires this.