Today the Pole Barn Guru addresses reader questions about moisture reduction in pole barn with dirt floor, what size windows can be added to a structure, and how to eliminate frost heave.

DEAR POLE BARN GURU: I have a 60 x 120′ pole barn with dirt floors and an insulated ceiling 18′ high. I believe the walls are also insulated but I haven’t checked. It stays very humid in there with the service door closed, which I like to do in the winter. There are 6 modestly sized windows but they’re 10′ high, hard to close in the rain and don’t ventilate much. I assume all this moisture is from the soil, is there a cost effective way to add a floor moisture barrier? ROSS in NORTHFIELD

DEAR ROSS: You are correct about where moisture is coming from – and it is made even worse in Winter, when ground outside of your building is frozen and inside your building is where all ground moisture is trying to escape (basically think of your building as being a cork pulled out of a genie’s bottle). While pouring a concrete slab on grade of a vapor barrier would be your best (and permanent) solution, concrete is costly. With this said, my best recommendation would be to remove top two inches of dirt inside of your building, making sure there are no sharp rocks projecting up above surface. Place a 15mil black vapor barrier across entire floor, overlapping seams by 12 inches and taping them tightly shut. Run vapor barrier up onto splash planks on walls (if possible) as well as sealing to each column. Cover vapor barrier with two inches of clean sand. You may need to mechanically dehumidify, in order to fully resolve your challenges.

DEAR POLE BARN GURU: Hello I am curious about window sizing in post frame buildings. Can I add any size window I want in any wall without affecting the structural integrity of the building? My largest windows are roughly 42″ wide by 64″ tall. WESLEY in DULUTH

DEAR WESLEY: Post frame buildings “work” due to their skin. Placing openings, without approval from your building’s engineer, could result in catastrophic structural failure.

For extended reading, please visit: https://www.hansenpolebuildings.com/2011/12/lateral-wind-loads/

DEAR POLE BARN GURU: The frost heave issue: how does a guy insulate his foundation? TONY in MARION

DEAR TONY: Most important for avoiding frost heave is having a properly prepared building site: https://www.hansenpolebuildings.com/2011/10/preventing_frost_heaves_in_pole_building_construction/
Here is information on insulating: https://www.hansenpolebuildings.com/2022/09/272982/