DEAR POLE BARN GURU:  I have a full size tennis court, we want to put a pole barn on the tennis court (we don’t play tennis) The barn would be 30 x 60 obviously leaving an asphalt perimeter larger than the barn around the barn – how would you seal the edges where the barn wall will meet the asphalt to prevent water intrusion? TENNIS ISN’T OUR RACQUET

DEAR RACQUET: I’m there with you, as I don’t play tennis either.

The nice big flat paved area where your tennis court is, makes for a very appealing location for a new pole barn. After all, it seems to be flat, and why not put the asphalt surface to good use?

Over the past three decades, I’ve seen numerous pole buildings constructed on top of existing asphalt, in situations very much like yours. And all, to the best of my knowledge, have been fraught with challenges.

First challenge – never is the “flat” tennis court actually level. This means a decision to either place the pressure treated splash boards to a level point (recommended) and then somehow fill the space in below them with something or to place the skirt boards with the contours of the asphalt (please do not even attempt to do this).

Second challenge – Assuming the splash boards were set to level, custom ripping pressure treated “filler” boards to fit between the splash plank and the asphalt is neither fun, nor easy. Plus, gaps will still exist.

Third challenge – and the root of the question, “how to seal the edges”? I’ve seen a myriad of products used, all asphalt based – none of which did a satisfactory job, over time. Asphalt expands and contracts greatly with heat and cold. The wood splash board does not. After a few hot/cold cycles, whatever seal was originally created, no longer exists and water is now flowing into the pole building.

There IS a solution, which will result in a far better outcome, as well as a much better floor than the asphalt tennis court.

Locate four corners on the asphalt at least four feet greater in width and length than the proposed building. After making sure the diagonal measures between the corners are equal (e.g. the market out location is square), snap chalk lines on the asphalt to follow the perimeter created by the corners.

Rent a walk-behind asphalt saw with a “wet blade” and cut along the chalk lines. The area inside the cuts can now be removed (requires a loader with a bucket and a dump truck to haul off the debris).

The building can now be constructed (to level) centered within the cut out area, and a concrete slab floor poured inside. Any water runoff from the surrounding asphalt can be captured in the area around the building. Fill in the space between the concrete and asphalt (outside perimeter of the building) with gravel.  This will allow the water to disperse.

The concrete slab can be set so top of the slab is higher than the surrounding asphalt, also minimizing runoff threats.

Bonus – concrete floors are much easier to clean and maintain, and ever try to run a creeper over asphalt?