Remediating Pole Barn Sliding Door Frost Heaves
Reader MARK in MARINE ON ST. CROIX writes:
“Poll barn door two 12 foot slider’s how to prevent frost heave s can’t open or close do I dig out under them and pour concrete or put 2 inch styrofoam any ideas?”
Harris Hyman, P.E. wrote this in a July 1994 article in Practical Engineering:
“As an engineer, I want to understand a little about the problem before I recommend corrective measures. Research work on frost heaving is somewhat limited, but there is a theory. Around the end of winter in cold regions, the earth develops a characteristic temperature profile: At the surface, the earth takes on the day’s temperature. But a couple of inches below, the ground temperature cools to approximately the February average temperature of the region. As we go deeper into the earth, the temperature rises, until several feet deep it reaches the annual mean temperature of the area.
The soil usually reaches its coldest temperature in March, when the freezing point reaches down to the region’s frost line. Below this depth, the soil and groundwater almost never freeze. But at the frost line — the 32°F point — the groundwater freezes, forming a thin sheet of ice. In soils that are porous enough to allow moisture to move, more groundwater touches this ice. The groundwater accumulates, freezes, and builds up into a bulge called an ice lens, which might be anywhere from several inches to a few feet across. The bulging ice lens pushes the earth above up into a frost heave. Aggravating the effect is surface melting, which also occurs at the end of March. The snow melt water moves through the ground, touches the ice lens, and adds to the bulge.
This is why, every spring, rural roads up North develop sinuous dips and dives. The ice lenses form during the winter, pushing up spots on the asphalt surface. When the weather warms sufficiently to melt the ice lenses, the unsupported asphalt sags and leaves low spots and potholes. On major highways, which cost a lot more to build, the base layer is sufficiently permeable to carry away groundwater, so heaves are rare.
Ice is fierce stuff. While most substances expand as they become warmer, ice actually expands as it gets colder, with the maximum expansion at about 28°F. When ice is confined, it can exert pressures from 20,000 to 80,000 pounds per square foot. There is almost no way to contain pressures like this; other solutions must be found.
The theory about ice lenses corresponds pretty well with the experience of engineers and excavating contractors. The most interesting implication is that heaving needs two things: cold and water.
This fact gives us our solution: Remove the water. Drainage is the one solution to heaving that does work most of the time.”
I would start by getting rid of any water. Slope ground away from building by at least 5% for 10 feet. Gutter downspouts need to discharge at least 10 feet away from building. Consider a French drainage system.
If this does not solve your issues, you could excavate to below frost line (I have had frost over seven feet deep not far away from you in Northeast South Dakota) and pour a concrete wall across your opening. If wall was thicker at base than top would also help minimize heave potential. Or, you could attempt to solve by pouring a concrete wall say 30″ deep, then insulate each side of wall down two feet and then out horizontally two to four feet with R-10 or thicker rigid insulation boards. Why both sides? I am assuming your pole barn does not have a concrete slab on grade and is unheated.
“I read your blog often and I truly appreciate the wealth of knowledge you openly share. I am in the process of starting construction on a hybrid steel shop that will house a small apartment that the wife and I will move into once its finished. We will sell our current home and then build a smaller house adjacent to the shop. 50 X 80 with 24′ wide mezzanine on one end. My questions are centered around wall/roof construction as well as proper insulation. Roof: I plan to install a standing seam roof with ice/water shield over 5/8 plywood. As you are aware, with hybrid steel it is hard to ventilate the roof with this type of construction. This downfall didn’t outweigh some of the benefits so this is what I am stuck with. Would like to understand some insulation options. Note: I do have the building designed to handle the loading of a couple of cupula’s and have considered making these passive and active ventilation points. (Exhaust fans with some louvers that I have yet to get the details figured out on)Walls (2 options): (Note: I prefer not to plan or have to always be fully conditioning the shop to 72 degrees…..I plan to have that ability by mechanical means but I don’t want to consistently have to be conditioning that much space, therefore I think i prefer the building to be able to breath out to the perimeter. I realize this may be tricky between the roof type and wall type)Option 1: metal siding – would like some input on wall and insulation construction based on the above notes of conditioning. Option 2: Hardie board vertical board and batten walls. Same as above, would like your input. There will be components on the first floor and second floor that make up the apartment space. Our approach on insulation and wall construction may change within those enclosed spaces may vary as they will be conditioned separately from the open shop space. Hope you can help shed some light on this approach and again thank you for your time and knowledge. Thanks!”
To reach two hours, you should have two layers of 5/8″ Type X on each side of your framed wall. You also need to insure any rain or snow coming off your roof does not land in your neighbor’s yard. This will entail a slight setback to allow for gutters and you will need a snow retention system on this side of your roof (this is assuming we are discussing an eave side and not an endwall).
The main purpose of rain gutters is to protect a building’s foundation by channeling water away from its base. They also help to reduce erosion, prevent leaks in basements and crawlspaces, protect painted surfaces by reducing exposure to water, and provide a means to collect rainwater for later use.
