Minimum Floor Slope Requirements for Exterior Walkways

[BoddaGetta]

I have an exterior elevated walkway that is exposed to the elements. The walkway is used as access for exterior doors on the elevated level. In some areas, the walkway actually slopes back in toward the building and water is leaking into the the building by migrating around the door threshold. I have reviewed the construction drawings, and the walkways are shown as being flat. Is there any code provisions that would have told the contractor to provide a mimnimum slope away from the building?

 

[ishvaaag]

This is as in roads and pavements, usually 1.5 or 2% should be selected to have some chance of the water drift towards drainage points. Even at these slopes a little wind may impel the water towards the walls hence codes use to ask for 8 to 10 inches of vertical waterproofing there.

 

[ishvaaag]

By the way I have been being unable to post for some time and unknown reason... Hope it is solved.

 

[racookpe1978]

Blunt logic: "The walls and roof in a properly constructed building should keep the water out of the interior of the building; and all rainfall should be discharged away from the basement, cellar, or slab so as to prevent water from getting inside the building."

If your building leaks (gets water into the inside of the building) when it rains, then you have a claim against the contractor.

 

[jgailla]

I'm in civil, so no elevated walkways, but on the ground you should have at least a 1% slope away from the building.
If the engineer detailed an exterior walkway as flat, I would think the engineer bears some of the blame.

 

[woodman88]

The closest requirements I can find in the 2003 IBC is (as jgailla stated it is concerning the grading away from buildings)
"1803.3 Site grading. The ground immediately adjacent to the
foundation shall be sloped away from the building at a slope of
not less than one unit vertical in 20 units horizontal (5-percent
slope) for a minimum distance of 10 feet (3048 mm) measured
perpendicular to the face of the wall or an approved alternate
method of diverting water away from the foundation shall be
used.
Exception: Where climatic or soil conditions warrant, the
slope of the ground away from the building foundation is
permitted to be reduced to not less than one unit vertical in
48 units horizontal (2-percent slope).
The procedure used to establish the final ground level adjacent
to the foundation shall account for additional settlement of
the backfill."
In the 2009 IBC it is now Section 1804.3 with additional comments.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[woodman88]

Sorry just found this section 2003 IBC Section

"106.1.3 Exterior wall envelope. Construction documents
for all buildings shall describe the exterior wall envelope in
sufficient detail to determine compliance with this code.
The construction documents shall provide details of the exterior
wall envelope as required, including flashing, intersections
with dissimilar materials, corners, end details, control
joints, intersections at roof, eaves or parapets, means of
drainage, water-resistive membrane and details around
openings.
The construction documents shall include manufacturer’s
installation instructions that provide supporting documentation
that the proposed penetration and opening
details described in the construction documents maintain
the weather resistance of the exterior wall envelope. The
supporting documentation shall fully describe the exterior
wall system which was tested, where applicable, as well as
the test procedure used."

In the 2009 IBC it is Section 107.2.4.
Note the " means of drainage, water-resistive membrane and details around openings."

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[Ron]

1008.1.4 Floor elevation. There shall be a floor or landing on each side of a door. Such floor or landing shall be at the
same elevation on each side of the door. Landings shall be level except for exterior landings, which are permitted to
have a slope not to exceed 0.25 unit vertical in 12 units horizontal (2-percent slope).

Similarly, if you have a walkway with multiple doors, the cross slope (perpendicular to the direction of travel) should be 2%.

Hey jgailla....check a little closer....that should be 5% away from the buildings.

 

[racookpe1978]

OK. So the "rules" exist, and are clear with respect to intent and size of the slope for such walkways.

Is it now a failure on the part of the builder who did not make the walkway slope =- and so cause the standing water and leaks; or on the drafter/engineer who may or may not have explicitly "told" the assumed competent builder to make the walkway slope away from the door with a note or drawing reference?

As always, who pays when an error is made?

 

[Ron]

Sorry guys...should have included the citation: 2009 International Building Code. Similar exists in the Florida Building Code.

 

[jgailla]

Ron,
That was a little embarrassing. I realized it after I posted.

 

[Ron]

jgailla...no big deal...been there, done that numerous times!!
Knowing your penchant for technical accuracy, I figured a typo!