Application of R405.1

[Rraddish]

Good afternoon

Would like to hear your opinion on R405.1

Construction is wrapping up on a structure that will have a rooftop pavilion and storage on the GL.

A GC and I are disagreement about R405.1 and if it applies to our project.

The GC's opinion is that R405.1 only applies to habitable basement space. He does not have to provide foundation drains.

My interpretation is that R405.1 applies. Storage is usable space. Two of the walls are below grade, so it is enclosed by a concrete foundation that retains earth. He needs to install foundations drains.

I've attached the engineers plans for reference.

R405.1 Concrete or Masonry Foundations
Drains shall be provided around concrete or masonry foundations that retain earth and enclose habitable or usable spaces located below grade.
Drainage tiles, gravel or crushed stone drains, perforated pipe or other approved systems or materials shall be installed at or below the top of the footing or
below the bottom of the slab and shall discharge by gravity or mechanical means into an approved drainage system.

 

[ICE]

If the structure is a dwelling that is regulated by the Residential Code and the exception does not apply, then I agree with you.

Exception: A drainage system is not required where the foundation is installed on well-drained ground or sandgravel mixture soils according to the Unified Soil Classification System, Group I soils, as detailed in Table R405.1.

 

[Mr. Inspector]

Go with Ice