Storey/Grade question

[kiwijbob]

This should be simple but I constantly scratch my head on it. Ok, defined terms 1.4.1.2 - First storey means the uppermost storey having its floor level not more than 2m above grade.
Is that an average of 2m? Where is the first storey on this building? Figure A-1.3.3.4.(2) dodges the question IMO, there should be a building C illustration. And don't concern yourself with the practicalities of the grade I've illustrated.

 

[Inspector Gadget]

This should be simple but I constantly scratch my head on it. Ok, defined terms 1.4.1.2 - First storey means the uppermost storey having its floor level not more than 2m above grade.
Is that an average of 2m? Where is the first storey on this building? Figure A-1.3.3.4.(2) dodges the question IMO, there should be a building C illustration. And don't concern yourself with the practicalities of the grade I've illustrated.
View attachment 14434

That's a four-storey building. Any side that has a floor level greater than 2m from finished grade (excepting localized depressions) has to be treated as a storey.

The 1995 part 3 illustated guide has some good language/drawings on this.

https://nrc-publications.canada.ca/eng/view/ft/?id=f4c59aa5-16df-4b40-b9db-d6c65cae71de

 

[kiwijbob]

Cheers, I do prefer that diagram. So if you have a basement garage (9.10.4.3) under the residential building I have illustrated above, it must be a 4-storey building and it can never be a Part 9 building with the drop in grade for the access ramp required to drive into the parking basement or would that fall under a "localized depression"?

 

[tmurray]

Keep in mind the definition of "grade" as well.

Grade means the lowest of the average levels of finished ground adjoining each
exterior wall of a building, except that localized depressions need not be considered
in the determination of average levels of finished ground.

This means we average the grade level for each side of the building and the lowest side is how we determine the first storey. It would not be possible to determine if your example is above or below the 2m threshold without knowing the horizontal distances of the changes in grade height.

If it is a drop just for the access, then it can be considered a localized depression. It can't be the whole side of the building. Normally, we would see retaining walls used for this type of depression.

 

[Inspector Gadget]

Cheers, I do prefer that diagram. So if you have a basement garage (9.10.4.3) under the residential building I have illustrated above, it must be a 4-storey building and it can never be a Part 9 building with the drop in grade for the access ramp required to drive into the parking basement or would that fall under a "localized depression"?

The parking garage entry could be considered a localized depression in this case. It would depend on the dimension of the side and the dimension of the entrance.

 

[steveray]

Here is how the non-metric code people do it:

[BG]STORY ABOVE GRADE PLANE. Any story having its finished floor surface entirely above grade plane, or in which the finished surface of the floor next above is:
1.More than 6 feet (1829 mm) above grade plane; or
2.More than 12 feet (3658 mm) above the finished ground level at any point.

 

[Yankee Chronicler]

Here is how the non-metric code people do it:

[BG]STORY ABOVE GRADE PLANE. Any story having its finished floor surface entirely above grade plane, or in which the finished surface of the floor next above is:
1.More than 6 feet (1829 mm) above grade plane; or
2.More than 12 feet (3658 mm) above the finished ground level at any point.

And our definition of Grade Plane doesn't allow excluding localized depressions.

[BG] GRADE PLANE. A reference plane representing the
average of finished ground level adjoining the building at
exterior walls. Where the finished ground level slopes away
from the exterior walls, the reference plane shall be established
by the lowest points within the area between the
building and the lot line or, where the lot line is more than 6
feet (1829 mm) from the building, between the building and
a point 6 feet (1829 mm) from the building.

 

[kiwijbob]

It's not an issue I'm dealing with currently, it's just something that keeps annoying me that I was looking for some clarity on which I now have. I appreciate the responses above and I'll sleep a little easier now that I've ironed that wrinkle out.....on to the next wrinkle!