Thread: Grading above slab level in garage

I inspected a new home today, the garage slab was lower than the rest of the homes slab by app. 12".. the garage slab was lower than the grading by app. 12", I could tell someone had removed the efflorescence w/ a pressure washer as a bit was still visible at the block inside the garage, I wrote it up as in need of evaluation, builder says A-OK, can anyone give me a code reference or tell me I'm wrong as to grading should be below slab level??

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I don't think a code reference exists. Below-grade garages are pretty common in many parts of the country

You saw it so you can apply common sense and hold your ground. If it's that bad you don't need code. Did you see what might be potential for flooding in the garage?

It's hard for me to comment on it since I didn't see it. It may be ok or maybe not. With the info you provided, I'm imagining anything between, "its ok to...its a total disaster"

Got any pics?

Here are some short and sweet code sections, I did not include the entire code section for each as they are rather long.

- R406.1 Concrete and masonry foundation dampproofing. Except where required by Section R406.2 to be waterproofed, foundation walls that retain earth and enclose interior spaces and floors below grade shall be dampproofed from the top of the footing to the finished grade. Masonry walls shall have not less than 3/8 inch (9.5 mm) portland cement parging applied to the exterior of the wall. The parging shall be dampproofed in accordance with one of the following:

- R406.2 Concrete and masonry foundation waterproofing. In areas where a high water table or other severe soil-water conditions are known to exist, exterior foundation walls that retain earth and enclose interior spaces and floors below grade shall be waterproofed from the top of the footing to the finished grade. Walls shall be waterproofed in accordance with one of the following:

Then there is floodproofing and flood hazard areas.

- R309.5 Flood hazard areas. For buildings located in flood hazard areas as established by Table R301.2(1), garage floors shall be:
- - 1. Elevated to or above the design flood elevation as determined in Section R324; or
- - 2. Located below the design flood elevation provided they are at or above grade on all sides, are used solely for parking, building access, or storage, meet the requirements of Section R324, and are otherwise constructed in accordance with this code.

- R324.1.2 Flood-resistant construction. All buildings and structures erected in areas prone to flooding shall be constructed by methods and practices that minimize flood damage.

And then, of course, there is the code of common sense which tells you that any floor located below exterior grade is going to have leakage and water into it if the walls are not fully and properly waterproofed ... but that is common sense and common sense seems quite uncommon in construction.

The original post seemed to be asking for a code section that prohibits grading above slab level. It's clearly not prohibited by code. Obviously, when the slab is below grade, there are dampproofing and other precautions needed.

Also, the OP said that it's new construction. If it's new construction, the efflorescence might be simply due to the water evaporating from the curing concrete, but it could indicate a moisture problem (failure to dammproof, waterproof, install perimeter drains, etc., etc).

Originally Posted by Steve Frederickson

The original post seemed to be asking for a code section that prohibits grading above slab level. It's clearly not prohibited by code.

Not so fast, there.

Go back and digest those code sections again ...

It is "prohibited" if those other things are not done and accounted for.

Hopefully the pic uploaded for you guys to see, thanks for the replys so far.. Kenny

Looks like they had a drainage problem, so instead of cutting the soil down and making a swale to drain the water away from the structure someone simply added some soil and brought the grade up ... up too high and now there are water intrusion problems - as one would expect.

That is not rocket science - raise the water level outside and the water will find its way down and inside.

What is the exterior covering on the sidewall of the garage? Does that brick veneer go down the side too? If not, is the grade in contact with concrete only or other types of siding?

If that grade is only in contact with concrete or masonry products, how is the water intrusion issue any different than it would be on a designed sloped lot? If the proper water proofing provisions were done, what would the problem be?

Originally Posted by John Dirks Jr

If that grade is only in contact with concrete or masonry products, how is the water intrusion issue any different than it would be on a designed sloped lot?


If the proper water proofing provisions were done, what would the problem be?

"If the proper water proofing provisions were done"

Therein lies the key to the entire construction industry, whether it be foundation walls, WRB to above grade walls, flashings at windows, doors, etc., and especially this part "If the proper ... were done, what would the problem be?" - that could be applied to the entire structure and everything which keeps home inspectors in business.

Vinyl siding at the sides, grading below that by app.8".. I sent the report and told them to have the dampproofing verified by raking back the soil as it should eisily be seen, if not have them correct it but get a guarantee in writing. They want the $8000 credit so I told him worse case scenerio when you sell you remove the a/c, correct the grading and replace it, I figure around $3500 if it can even be done since we don't know if the idiots buried the elec., gas etc. that runs right through there the right depth.. gotta love these builders. I may have over stepped it a bit but won't be the first time.