Hello folks!

The theme of this post, in the spirit of MacGyver, is improvise! As stated in the last blog, experiments and plans rarely go exactly as expected and this still holds true for my continuing study of anti-efflorescence coatings on masonry.

Since I last posted, I have started the driving rain cycles on all seven of the walls. However, this process was not smooth sailing. W1 was my guinea pig wall, and as it turns out, the tub in which the wall was built was not adequate for containing the water during the three hour rain cycle. Therefore, I spent the entire three hours mopping up the water that was not contained by the tub, and in all honesty, I barely kept up with the amount of water that was on the floor. I knew that something had to change before starting the next cycle.


W1 with Rain Device

W1 First Rain Cycle (Let it Rain!)

I enlisted the help of Catherine Cooper, the new Technical Services Research Associate at NCPTT, and we came up with a plan to build a rain shield to help contain the water that was bouncing off and missing the wall entirely. We built this rain shield out of PVC pipes and a shower curtain.

Catherine Cooper and Marissa Bartz measuring the PVC Pipe


Catherine Cooper and Marissa Bartz cutting the PVC Pipe


Catherine Cooper and Marissa Bartz assembling the PVC Pipe Rain Shield


Catherine Cooper and Marissa Bartz attaching weighted feet to pipe


Fully Assembled Rain Shield


Another View of Fully Assembled Rain Shield

Once we assembled our rain shield we tried it on W2, only to discover that not much of the water on the floor was a result of cast off. Rather, it was a result of four small holes where the handles connect to the plastic bin in which the wall sits. These holes were beneath the drainage tube that was attached to bin, resulting in the leak. Therefore, Catherine and I spent another driving rain cycle mopping and controlling the water on the floor in the lab. Although our rain shield didn’t solve the problem, it did help us realize where much of the water was coming from; so it was successful even though revisions needed to be made.

Finding my Inner Cinderella

Catherine Cooper Mopping like a Champ!

After discovering the holes, I decided to fill them with silicon using a caulking gun, in hopes of preventing the water from leaking through the holes before reaching the drainage tube. This solution seemed to work, but we saw that the green hose that is attached to pump leaks and leaves a significant amount of water on the floor as well. We decided to place the rain apparatus in a plastic bin similar to the ones the walls were built in to catch the run-off from the hose.

Rain Device in Plastic Tub in Front of Wall


The bin proved useful in solving our run-off problem, but also added some problems of its own. The main problem was that the bin was not level, which caused the rain apparatus to fall forward or backward, despite our best efforts to find its equilibrium. We decided to add metal legs to allow it to lean back a little, a bit like an easel. However, we still had some issues with the apparatus falling forward, since there is not much space in the bin to extend the legs.

Added Metal Leg for Stabilization

In order to solve this latest problem, we attached U-shaped PVC pipes to the rain shield on both sides of the rain device that would help stabilize it and prevent it from falling forward or backward. Finally, we had success. It was not the prettiest solution, but it works and that is what counts. We eventually found a more elegant solution using metal laboratory clamps that attached to the rain device and the rain shield’s PVC pipes. The metal clamps make it much easier to move the shield and rain device between walls. The last modification that we performed on the rain device was switching out our cardboard and garbage bag trough with a plastic one, which holds up significantly better

U-shaped PVC Pipe for Stabilization


Metal Holders that Replaced U-shaped PVC




Plastic Trough that Replaced the Cardboard

Despite the many unexpected obstacles that arose while performing what I hoped would be a simple task of placing the rain apparatus in front of a wall and letting it go, it all worked out in the end and I learned much as I went. One lesson is that it is important to roll with the punches and persevere; and with a little help from my friends (yes, I am quoting the Beatles in their infinite wisdom), most problems are not nearly as insurmountable as they seem and can be solved with the supplies that are on hand.

Fully Assembled and Finished Rain Shield at Work!

Well, folks that is all I have for now. I will post again after the rain cycles with my observations and any other challenges that arise as the rain continues.

National Center for Preservation Technology and Training
645 University Parkway
Natchitoches, LA 71457

Email: ncptt[at]
Phone: (318) 356-7444
Fax: (318) 356-9119