Degradation of plaster wall at our southwest edge

TWO WEEKS AGO, I hosted the representatives of two waterproofing companies. It prompted me to take a more careful look at the plaster-covered concrete wall at the southwest corner of our property. Its degradation is now obvious, as the result of water damage. It took a big hit this past winter.

(As usual, click/tap on an image to enlarge it.)

Below the jump, this post discusses the condition of what I am calling the “southwest edge” of our sanctuary property.…

This is a public-facing wall, seen by passersby on Main Street. So it needs to look good, both as a representation of Mishkon itself, and for being a good neighbor in our commercial district.

True, this section of wall has been better maintained (= painted more often) than the south wall along our neighbor’s parking lot, which we redid last summer. But even here, the concrete has consistently gotten damp enough that, over time, the plaster has delaminated in places. (Evidence: It makes a hollow sound when you tap on its face. Not to mention the horizontal cracking along the top lip that protrudes below the portico.)

One contractor opined as follows:

You have a water issue coming from inside the planter where the plants are. It pressurizes and then blows through the wall and out where the bubbles are.

Yet that’s not the whole story, as a closer inspection shows. Rather, the wall section that is below the portico is likewise water damaged—not only the section along the planter. And the portion of the planter that is lowest (in front, under the shade tree) is actually in better shape than where the wall is more exposed to rain and sun. 

That is, the main cause of trouble appears to be rainwater, which not only gets into the exposed planters (which have no interior waterproofing), but also percolates through the sandstone caps of the planters and the portico. 

Meanwhile, affecting the portico section surely is the collected rainwater running down the back of the portico stem wall from the corner column above. Here are photos that Ruben took from under the portico in February, after a major storm. We are looking at the back side of the foundation wall in question. 

Water puddles onto the plaster ceiling of the storage room below.

Predictably, that water not only runs downhill, but also it percolates through the concrete wall—ruining the plaster adhesion on the outside face.

There may well be rebar corrosion behind the delaminated plaster. We won’t know how bad that is until the wall is scraped.

Conclusion: This translates into spending more money.

In conclusion, this wall section needs to be repaired at the same time as the façade proper is being waterproofed. However, this task was not included in the previous estimate for the façade project, which served as the basis for the board’s expenditure authorization. I.e., we may need to increase the $$$ limit, to cover the added cost.