Preservation Myths Debunked (Part II)

Editor's note:  This is the second in a series of two articles that puts to rest common misconceptions about historic preservation.

Last month in Colorado History NOW, we learned that historic designation can create financial opportunities for historic building owners, that old windows are frequently better than replacements, and that with a little work, old buildings can be lead and asbestos safe.  We received such a positive response from that article, we thought we'd tackle a few more myths before examining some case studies.  Read on for more preservation tall tales-debunked!

Myth #1:  Old wood or brick should always be covered with stucco or replacement siding to protect it from the elements; it will save you maintenance time and money.

FALSE!  Covering original materials may appear to be a time- or money-saver, but it could potentially harm the building's character and physical health.  By the time replacement materials start to save you money on maintenance, sometimes they start to need maintenance themselves!

A structure's historic material is an important aspect of its significance.  When you cover up or destroy the original materials, you compromise the entire structure's basic integrity.  Doing so can also cause physical damage to the original wall material.

Applying a new vinyl or aluminum shell may cover imperfections in brick and wood, but it will also hide problem indicators.  Spalling (flaking or crumbling) brick and buckling paint are clues that indicate more serious problems.  If siding covers the materials, you can not see the problem, let alone address it.  Also, nail penetrations from attaching aluminum or vinyl siding can cause masonry to crack or spall.  Creating any holes in masonry will create places for water to sneak in, speeding up the wall's deterioration.

Replacing or covering historic material with new material implies that new material is somehow superior in quality.  In reality, maintenance, repair, and retention of historic materials are always the most architecturally appropriate and usually the most economically sound measures to preserve the unique qualities of historic buildings.

Myth #2:  Historic brick is best cleaned by sand blasting (or with glass beads, water, etc.).

FALSE!  Abrasive cleaning, those techniques that physically abrade the wall surface, are responsible for causing a great deal of damage to historic building materials.

Abrasive cleaning does exactly what it promises: it scours the surface to remove dirt and paint, but at the same time it removes delicate and irreplaceable historic material.  On brick, abrasive methods remove the hard, protective outer surface, or "fire skin," causing the brick to act as a sponge, soaking up water into the walls rather than shedding it.  No sealant or covering can adequately replace that skin.  Abrasive cleaning also loosens the bond between brick and mortar.  It creates cracks and enlarges existing cracks, giving water a place to enter and cause damage.  Similarly, wood grain can be raised away from its connective tissue by abrasive cleaning, giving water a place to enter and cause damage.

There are many other means of removing dirt, stains, and paint that are less damaging.  First, assess the condition of the material (brick, wood, etc.), and justify why you're cleaning the building.  Ask yourself if you are cleaning to remove a problem coating or are you risking damage just to make the building look new.  Finally, determine the best and gentlest means possible to clean the building.  That might be a low-pressure water wash, scrubbing with a natural bristle brush, steam cleaning, or gentle chemical cleaners, usually followed by a pure water wash.

Myth #3: You can never build additions to your historic building.

FALSE!  New additions have either the potential to destroy a historic building's significant historic materials and features, or to give it new life-or both!

Keep in mind these three keys to successful addition design: preserve significant historic materials and features, preserve the historic character, and protect the historical significance by making a visual distinction between old and new.  Making the size, scale, massing, and proportions of an addition subservient to the original building, or creating an infill addition or connector to a subservient new addition should result in a more sensitive and successful addition.

BY RACHEL SIMPSON, State Historical Fund Technical Advisor

For more information about:

These publications are available from the State Historical Fund, the Office of Archaeology and Historic Preservation, and the National Park Service.