Moisture Management of Parapet Walls

[Marcel R. Cyr]

Masonry Technology Incorporated

MTI
Of Parapets and Peril


Most of us probably give little, if any, thought about buildings with parapet walls even though they proliferate the landscape. Drive through a modern suburban shopping area and you’ll evidence structure after structure crowned with a parapet. From big box stores to fast food shops, buildings featuring parapet walls are literally everywhere.
One of the most famous architectural examples involving parapet walls is Frank Lloyd Wright’s Fallingwater house in Pennsylvania. Probably most of us are aware of it; however, are you aware of the many structural crisis experienced at Fallingwater? The main cantilevers that allow the house to stretch out over the stream nearly collapsed (and would have had then been built according to Wright’s original specifications). In addition to reworking the cantilevers and adding cables for support, leaking roofs, weak parapet walls, substandard steel windows, and many other issues have needed repair or replacement totaling more than $11 million dollars in upgrades.



Parapet walls can add a unique beauty to a structure, just as they do at Fallingwater and many other locations. Parapet walls offer many advantages to architects, contractors and building owners.

• They can be easily adapted to a wide array of desirable facades
• They are excellent for hiding mechanical equipment that needs to be placed on a roof
• They help prevent roof edge blow off by diverting winds and air currents upward
• They can be a stable termination point for roof edges and flashings

However, their use demands careful study and implementation. One of the main issues with parapet walls is the need for moisture management.


Download MTI's complete article http://www.mtidry.com/news/ParapetWallArticle.pdf.

Good Information

[Bob Elliott]

Got that email today to Marcel.Lots of good info, so it pays to sign up .

[ROBERT V. YOUNG]

You know as well as most roofers know, or more so a brick layers, will point out the obvious problems with parapet walls.
I pay particular attention to the structure.
It is always the weakest link in that systems chain.
The brick ( if Brick ) at the top most 10 to 20 courses, are with the littlest weight for bonding during and after they have been installed.
We use to rest cinder block at the end to rest there for days before cleaning with acid.
Coupled with improper flashing and you have the stage set for observation plus maintenance if leaning or bowed.
They should be paid attention too when doing a home inspection.
Also the flashing. That the weak link. The flashing's and coping's after a re roof never fit. The roof is bigger if not striped.
The tin wrist locks are broken and seldom reset.
They never reset the tin properly.
The wall acts like a chimney allowing vapor and heat to channel up the wall. If not sealed right it also allows cold air to transfer into the cavity when the home is on a cool down. AT NIGHT.
I have opened many walls to see them lined with frost.
Mostly pre 1930's.
New homes also have problems.
Good point out Marcel.