MTI Uses Google SketchUp, Google Earth

Google Earth Tour

MTI now has 3D models available in the Google SketchUp online warehouse. All of our products and many of our details can be viewed here. We are able to customize any detail in SketchUp to meet your specific needs. Masonry Technology has also placed to-scale SketchUp models of some of our most noteworthy projects in Google Earth for a real-world look. Check out the Google Earth link on MTIdry.com to take a tour of these projects!

L+R Weep Screed™ Function

In our Fall 2009 newsletter, we promised a future article on the function of metal weep screeds on the market. Masonry Technology’s L+R Weep Screed™ is the only metal termination specifically designed to accommodate a rainscreen drainage plane material and allow all the moisture to escape, every time.

L+R Weep Screed™

Most of the existing metal weep screeds were designed prior to the existence of any real rainscreen drainage plane technology and have a somewhat less than consistent performance history. They were, and are, a focus stress-point where cementitious materials and metal meet. The resulting shrinkage leaves voids/unpredictable openings in the rainscreen system that allows moisture to enter. In many cases the design of the weep screed itself would hold moisture through freeze-thaw cycles. Unfortunately, it seems that the design history of these devices has little foundation in moisture management.

To perform effectively, weep screeds must have drainage capacity equal to the rainscreen drainage planes they terminate. With the advent of real rainscreen drainage plane technology that effectively directs more moisture from a high entrance point to a lower point in the exterior building envelope, inadequate weep screed designs will become even more ineffectual.

As mentioned above, MTI’s L+R Weep Screed™ does not present this issue. Its overall design, which includes 1″ drainage holes, permits all of the water traveling through the drainage plane to escape from the building envelope in a timely manner. See L+R’s product specifications at MTIdry.com for more information.

Lstiburek’s “Mind the Gap, Eh?” Article

In a recent ASHRAE Journal article, Mind the Gap, Eh?*, recognized entrapped moisture expert Dr. Joseph Lstiburek stressed the importance of drainage planes in the  exterior building envelope. The article looked at the trends in building envelopes over the last 100 years and showed how the adoption of OSB, XPS and certain WRBs has increased the entrapped moisture problem.

Lstiburek states that when the wall is sheathed with OSB and housewrap and the veneer is an airtight cladding, “we have to help out the drying part of the equation. To help out with drying, we need an air gap between the cladding and housewrap/OSB interface, especially with airtight claddings, such as stucco, manufactured stone veneer, and especially where cavities are insulated with those new fancy spray insulations (such as cellulose, or spray foam or blown-in-batt). The air gap is simple, elegant and unbelievably effective in helping out drying. Back vent your cladding and be happy.” (Lstiburek, p. 58). He goes on to say that a 3/8″ or 10mm gap is a safe amount of space. An effective rainscreen drainage plane creates this permanent, predictable void/air gap.

Masonry Technology, Inc. has been promoting this idea for years. That’s what we are all about – creating a predictable void behind the veneer to promote drying and pressure equalization. That’s what our Sure Cavity™ products do! Canada seems to understand this issue better than the U.S. and has made it code.

There are many important points for including a predictable air gap between the veneer and OSB/housewrap made by Lstiburek in this article, but here are a few that need to be stressed:

• “The air gap’s primary function with stucco is to prevent the buildup of hydrostatic pressure…”
• “There is no way that an exterior OSB skin that gets wet on a SIP can dry inwards.”
• “Most housewraps don’t work.”
• If foam sheathing is used instead of OSB/housewrap, there are some things that need to be addressed. “The water vapor impermeability of foam sheathing must be dealt with,” and, “we have to control hydrostatic pressure.”
• “If you have wood or wood-based siding, the wood rots, and the paint falls off because the wood or wood-based siding cannot dry into the foam sheathing. Guess what fixes this? Yes, you guessed it, a small air gap…” (Lstiburek, pp. 59-61)

We can continue to be in denial that a permanent, predictable void (a rainscreen drainage plane) behind the exterior veneer in our rainscreen building envelope isn’t necessary, but the mold and sustainability issues won’t disappear. I encourage you to read Lstiburek’s Mind the Gap, Eh? article available for download here.

I also encourage you to visit www.MTIdry.com and take advantage of our Testing and Education sections for the science behind effective drainage planes and weeps. Then take a look at our HyperSpecs® section for drawings and animations on how to implement them in almost any wall detail.

* Lstiburek, Joseph W. Ph. D.  “Mind the Gap, Eh?”  ASHRAE Journal January (2010): 57-63. http://www.ashrae.org/.  American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Jan. 2010. Web. 29 Jan. 2010.

Daily Dose: Peter Eisenman Wins Wolf Prize

Peter Eisenman is one of two recipients of the 2010 Wolf Prize, awarded (this year) for architectural achievements. The prize is bestowed annually in the arts – a rotation between the disciplines of architecture, music, painting and sculpture. Eisenman is being honored for his conception and design of the Holocaust Memorial located in Berlin, Germany.

Eisenman's Holocaust Memorial in Berlin, Germany

Path through Holocaust memorial

2,711 rectangular stones, each of unique dimensions, populate the sloping ground between East and West Berlin. Bearing no inscriptions or adornment, these blocks take on the somber appearance of tombstones or coffins. Eisenman allowed for paths to wind through the blocks, recreating some of the disorientation and fear that the imprisoned Jews felt during their horrific experiences in Nazi concentration camps. Critics of Eisenman’s architectural tribute say that his approach is too abstract to convey his desired message of respect and homage, but I suspect that wandering through this maze of monuments would indeed be a sobering and chilling experience.

Individual blocks in Eisenman's Holocaust memorial

Sources:
http://architecture.about.com/od/greatbuildings/ss/holocaust.htm
http://jta.org/news/article/2010/02/03/1010458/american-architect-awarded-wolf-prize

Daily Dose: The Stonecutter

Today, there’s something a little different on the Daily Dose: a folk tale. The Stonecutter is a Japanese story of unknown origin that is similar to the moral fables of Aesop. The following is a creative synopsis of the tale found on Wikipedia; full-length versions can be found at various sites online. Enjoy!

“Once upon a time a stonecutter was working near the side of a mighty rock. As he stood to pause from his hard labor for a minute, he observed a local landlord and his party passing underneath the shade of the trees nearby.

When the stonecutter saw this rich man in all his comfort, his work suddenly felt heavier and harder to him. “Oh, if only I were a rich man,” he sighed, “how happy I should be!” Suddenly a voice answered from the mountain: “Your wish is heard; a rich man you shall be!”

Children's illustration

When the stonecutter returned home that evening, he found a magnificent palace where his hut once stood. The poor man was nearly beside himself with joy, and in his new life the old one was soon forgotten. One day, while he was walking around the marketplace, he felt the sun burn sharply on his face, and as he saw a prince, sitting in the cool shade of his carriage, he wished he was a prince. A prince he became, but still the sun scorched his face. The stonecutter then wished he would become the sun itself, and immediately it was granted.

As the sun, he felt mightier than all. His light stretched around the entire world and his rays shone on kings and fishers alike. But as he burned bright in the sky, a cloud moved in front of him and obscured his sight. “What is this!” he wondered, “a cloud is mightier than me! Oh how I wish I was a cloud.”

And a cloud he was, and he lay between the sun and the earth. He caught the sun’s beams and held them, and for days and weeks he poured forth rain till the rivers overflowed their banks, and the crops of rice stood in water. Towns and villages were destroyed by the power of the rain; only the great rock on the mountainside remained unmoved. “What is this!” he cried, “a rock is mightier than me! Oh how I wish I was a rock.”

And the rock he was, and gloried in his power. Proudly he stood, and neither the heat of the sun nor the force of the rain could move him. “This is better than all!” he said to himself. But one day he heard a strange noise at his feet, and when he looked down to see what it could be, he saw a stonecutter driving tools into his surface. Even while he looked, a trembling feeling ran all through him, and a great block broke off and fell upon the ground. Then he cried in his wrath: “Is a mere child of earth mightier than a rock? Oh, if I were only a man!”

And the mountain spirit answered: “Your wish is heard. A man once more you shall be!” And the poor man was content to remain a stonecutter for the rest of his life.”

Source:
http://en.wikipedia.org/wiki/The_Stonecutter
http://picture-book.com/taxonomy/term/124