Waterproofing the Base Plate

One of the few frustrating things about our Quonset is water leaks. The shell itself is engineered to be completely watertight. But, as with most well-planned projects, reality has a way of challenging the ideal. After checking all the bolts and tightening a few, we were able to seal all but a couple of leaks. The remaining few were due mainly to small tears in the metal at the bolt holes caused by over-stressing the skin in an effort to line up holes. After we made these mistakes a couple of times we realized our errors and corrected them. But the damage was done. 

      Our biggest problem was sealing leaks at the base, where the shell meets the concrete and where it ties into the base plate. We were advised to fill the void created by the shell meeting the channel with concrete, which we did. We also used a heavy application of caulking between the base plate and the concrete. In spite of this, when it rained, we had an indoor pool. We then caulked all around the concrete where it met the metal. It still leaked. We then coated the whole area with water-stop concrete, a kind of latex/cement material that is supposed to seal concrete and bond to metal…it still leaked. We caulked again…to no avail.

      In desperation, I started researching ways to solve our problem and came across a company called Hydro-Stop, out of Charleston, SC. Their website (http://www.Hydro-Stop.com) was intriguing and the concept looked promising. It seemed like a lot of work, but we were desperate. I contacted the company, told them of our problem, they invited us to visit and see for ourselves.  Hydro-Stop is one of those small companies (not yet regulated into oblivion) that offer a great product and excellent service. We met with Perry Smith, Charleston Plant Superintendent, and he gave us the tour. Fast-forward, we took home two buckets of Hydro-Stop sealer, a roll of fabric, and a bucket of color coating. The rest follows:

     Here’s our culprit. 

This is the base filled with concrete, caulked, then coated with water-stop concrete.

I decided to make a pattern and cut out pieces of the reinforcing fabric for each base juncture. 

My pattern was made of cardboard and I used a razor knife to cut each piece of fabric to fit the base plate shape.

Since the product is water base, it is very easy to work with and clean up after. 

Manufactured in Charleston, SC, Hydro Stop is shipped all over world for guaranteed, cost-effective waterproofing.

I simply brushed on a generous coat of Hydro-Stop sealer.

'Generous coat' means enough to bind the fabric to the cement.

While it was still very wet, I laid in the piece of pre-cut fabric.

The pre-cut fabric pieces made the job much neater and quicker.

I then coated and saturated the fabric with more sealer making sure the fabric was completely covered and no raw fabric showed through.

This process works very much like hand-layup fiberglass--except much easier and with no smell!

Making sure any air bubbles were pressed out and the fabric was completed covered with sealer; I gave it one final coat to smooth out the fabric texture.  

The polyester fabric is very easy to work with and soaks up the Hydro Stop readily.

Voila!

The finished job. Neat, clean, and effective. Our second phase of water/air-proofing the shell will overlay the top edge of our base covering.

      We have yet to apply the final color coat, but even after a tropical storm and several heavy rains, we leak no more! All in all, the process went quite smoothly. It took 10-12 minutes to seal each cavity. With 25 cavities per side, it took less than six hours to complete the project. The best part is—we now have a water-proof Quonset!

      Using Hydro-Stop to solve one problem has given us the solution to another problem. Since we plan to use the skin of our Quonset to provide us with cost-free air circulation, we need our structure to be air-tight as well. Our next Hydro-Stop project is to seal our entire shell with the same system we used on our base. Another bonus: we want to change the color of our Quonset, plus give it extra protection against the elements. With minimal preparation, Hydro-Stop bonds so well to the GalvaLume surface; it is an excellent coating for metal.

      Using the Hydro-Stop system, we can seal each joint, making our building completely water and air tight, plus, we can add color to the entire structure!