Extreme Weather Hits Home – Weblog

December 23, 2007

The Story Of Stuff

Filed under: Answers to Questions — Tags: , , , , , , , — John Banta @ 2:16 pm

Extreme Weather Hits Home, Protecting Your Buildings From Climate Change   I’ve posted “The Story of Stuff” with Annie Leonard here. This is worth seeing. It is broken into seven chapters here, or you can follow the link in my blogroll at the right to see the entire larger screen uninterrupted video. According to the producers:

“The The Story of Stuff is a 20-minute, fast-paced, fact-filled look at the underside of our production and consumption patterns. The Story of Stuff exposes the connections between a huge number of environmental and social issues, and calls us together to create a more sustainable and just world. It’ll teach you something, it’ll make you laugh, and it just may change the way you look at all the stuff in your life forever.”

 Chapter 1 – Introduction

Chapter 2 – Extraction

Chapter 3 – Production

Chapter 4 – Distribution

Chapter 5 – Consumption

Chapter 6 – Disposal

Chapter 7 – Another Way

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November 21, 2007

Basement Moisture Issues

Filed under: Answers to Questions — Tags: , , — John Banta @ 8:40 pm

Hi John,

I tuned in to WPR with Ben Merens earlier this week.  You were the guest and I heard you answer a question about how to deal with 100 year old block and mortar basement walls.  I was driving and could not write down the name of the plaster product that you recommended. The additional issue I have with my basement walls is that the previous owner painted them.
A lot of the paint is flaking off, but a lot is not.  I also notice the salty fuzzy stuff you were talking about.  What is the best way for me to deal with these walls to  preserve them and to make them look a little more uniform and attractive?  Also, there are a couple of cracks.  Any suggestions
there?

Thanks much for sharing your time and knowledge.
Barbara

11/21/07

Hi Barb,

A link to my interview with Ben is now posted on this blog under radio interviews, so you can listen to it again.  Here is some information on the topic from page 177 in my book Extreme Weather Hits Home, Protecting your Building from Climate Change:

Efflorescence and Spalling
“Efflorescence is generally a white- or light-colored powdery salt deposit that forms on damp masonry surfaces. It is sometimes confused with mold growth, but mold requires an organic nutrient like cellulose. Efflorescence is especially common after flooding has saturated masonry materials or in situations with inadequate drainage. As moisture flows through brick, concrete block, stone and other masonry materials it carries dissolved salts along. When the water reaches the surface of the material it evaporates, depositing the salt on the surface of the material. As long as the moisture can escape and doesn’t build up, the salt deposits are harmless, although unsightly. Placing a nutritive material such as gypsum wallboard against masonry materials exhibiting efflorescence will generally result in mold growth on the gypsum paper.”

“Some people have tried to halt the flow of moisture and salts by sealing the surface of the masonry. This reduces the flow of moisture and the salts no longer reach the surface where they can be seen. At first it may seem like a reasonable solution. The problem is the moisture flow still occurs, although at a reduced rate, so the salts continue to build up just under the layer of masonry instead of forming on the surface of the material. This sets up an osmotic gradient that can result in hydrostatic pressure causing the masonry to lose its structural integrity and slough away in a process called spalling. Most people have observed this in sidewalks or other cement with a thin layer of material that has come off in a sheet. Once the masonry has spalled, the flow of moisture and salts resumes and the efflorescence once again builds up on the surface. Repeated applications of sealant will repeatedly spall until the masonry’s structural integrity has been damaged. Many historic buildings, foundations and basements have been significantly damaged by the application of sealants. A better method for dealing with efflorescence on masonry is to coat the offending surface with a parge coat of plaster. This is a plaster material that is slightly softer and more porous than the masonry. As the moisture flows through the masonry, it continues through the parge coat and evaporates from the surface, but the salts remain behind in the parge coat. Eventually, when the salts become concentrated enough, the parge coat will slough away from the masonry and require cleaning and recoating with another layer of parge plaster. Since it is the parge that sloughs off instead of the masonry spalling away, there is no loss of structural integrity or damage to the masonry. Parge coats can provide very attractive finishes and are often dyed with mineral pigments to add color to the surface.”

There are a number of different parge coat plasters available. Thoroseal Foundation Coating http://thoroproducts.com/pdf_appl/appl_foundation.pdf can act as a parge coating when used as directed but is not considered a decorative coating.

You might consider using the Thoroseal Foundation Coating as the parge coat then a second coat of Thoroseal Water Proof Cement Based Coating http://thoroproducts.com/pdf_appl/appl_thoroseal.pdf  for an attractive top coat.

You may want to check out some web-sites that describe the process of applying a parge coating. It can be similar to applying plaster, Its heavy, hard work – so many people don’t want to do it themselves. If you do decide to try it yourself, practice in an inconspicuous place to make sure you can make it look smooth and attractive.

After re-reading your question I realized I didn’t address the paint. In order for a parge coat to stick the paint would need to be removed. My concern is that based on the age and condition, it is very likely that it contains lead.

The company I work for – RestCon Environmental can arrange for lead testing. Please send me a email at jbanta@restcon.com to set this up.

John Banta

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