Tag Archives: site grading

One End of My Pole Shed is Moving Up

One End of My Pole Shed is Moving Up

Pole Building Storage ShedReader JOEL in GULLY writes:
“I have a question for you, I built a 24 x 30 foot pole shed with ten foot side walls about 30 years ago, I dug the poles down 60 inches and the building sat perfect for 25 years, then a few years ago the one end started coming up out of the ground about 4 inches and that end has been moving up every year, as of now the south corner has lifted about 8 inches, I dug down in the corner post thinking a rock may have moved up under the post but there was nothing there, so what do you suppose has happened under the ground to start this ground shift? Water? I live in northwest Minnesota about 80 miles from Canada, and where the shed sits we never drive there, just curious.”

My best guess is underground water. Here’s a look at some options:

1. Dry Creeks
This is a subtle and creative solution for drainage issues and offers a bonus: it’s pretty.
A shallow trough is lined with stones or rocks, offering excess water a place to flow and runoff.

2. Trench Drains
This is a great choice for heavily paved areas such as driveways and parking lots. Trench drains are concrete-lined channels helping direct water flow while filtering out debris using grates or filters to reduce clogging.

3. French Drains
A more intricate method of controlling water flow around a building or property is by using French drains. This, and proper site grading, will probably achieve your best results.
French drains are typically perforated pipes channeling water in a specific direction. These pipes are usually covered with rocks and gravel to help with filtration, water flow and ensure pipes stay in place.

4. Site Grading
Site grading involves changing landscape to encourage water to flow in a desired direction — away from your building.
Many drainage issues stem from improper grading techniques during a building’s construction. At a minimum you want to grade at least 10 feet from your building with a 5% or greater down slope (this is also a Building Code requirement).

5. Dry Wells & Reservoirs
When surface water has no place to go, it pools and floods. Building a dry well underground, or a surface reservoir gives excess water a home. Swales fit into this category: https://www.hansenpolebuildings.com/2013/01/swale/

How to Keep the Water Out of a Pole Building

How to Keep the Water Out of a Pole Barn

The post frame (pole barn) building has moved from the farm to suburbia. With the transition in building uses, having water flowing into a post frame business or residence is far less than desirable.

Dear Pole Barn Guru: My parents lived in a pole barn “lodge”. When there was a lot of snow and it blew against the building, as it melted water would get in under the walls. Grading was away from the building. Was the slab not poured high enough? Is there a way to seal bottom during construction that maybe wasn’t done properly? We want to have a pole barn home built, but need to educate ourselves on these details to make sure the work is done properly. Carolyn in Cleveland

Mike the Pole Barn Guru answers:

My bride and I happen to live in a post frame home in South Dakota, where in both snows and blows. Our building also has a huge footprint, being 84 feet wide and 60 feet deep. A six inch snowfall easily results in a berm along each side several feet in height.

For our slab on grade building, we made sure to have some serious slope away from all four sides of the structure.

From the 2015 IBC (International Building Code):

“1804.4 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 measured perpendicular to the face of the wall. If physical obstructions or lot lines prohibit 10 feet of horizontal distance, a 5-percent slope shall be provided to an approved alternative method of diverting water away from the foundation. Swales used for this purpose shall be sloped a minimum of 2 percent where located within 10 feet of the building foundation. Impervious surfaces within 10 feet of the building foundation shall be sloped a minimum of 2 percent away from the building.

Exception: Where climactic or soil conditions warrant, the slope of the ground away from the building foundation shall be permitted to be reduced to not less than one unit vertical in 48 units horizontal (2-percent slope).”

Regardless of siding type, a high quality and well-sealed building wrap (https://www.hansenpolebuildings.com/2012/11/house-wrap/) should be placed under the siding with the bottom edge at the bottom of the siding.

With steel siding, inside closures (https://www.hansenpolebuildings.com/2015/12/the-lowly-inside-closure/) can be placed between the building wrap and the steel siding to fill the voids created by the high ribs of the steel siding.

For residential purposes, I would strongly encourage the use of a raised wood floor over a crawl space as a living surface. It will add to comfort and should pretty well eliminate any potential for water infiltration around the base of the living area.