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Restoration and Preservation
Avoiding Common Renovation Mistakes
While correcting mistakes others make in restoring old masonry structures could become a lucrative side business, it is obviously in the best interest of both the building and its owner to get it right the first time. Here are some avoidable mistakes people make when repairing or, worse, “improving” historic masonry buildings.
Mixing new with old
In addition, modern mortars and joint sealing compounds are stronger and stiffer than historic mortars, so when a wall moves the bricks are more likely than the mortar to crack. Whatever the mortar used, it must be softer than the masonry.
Testing the existing building to determine material properties and finding compatible replacements can take longer, but is worth the effort as it will avoid problems and callbacks.
Super-insulating an old masonry building also can cause moisture damage. Insulation keeps the outside of the wall colder, so moisture condenses and increases the risk of freeze-thaw damage. If insulation is added, it should have a value no higher than R-10 and should not incorporate a moisture barrier.
Most moisture damage to old buildings comes from poor drainage, so inspecting and repairing (or adding) downspouts and flashings to keep water off the wall are effective repairs.
Doing too much
Some building owners literally want to raise the roof to increase space without altering the façade of a historic building. To do this successfully, the contractor must evaluate the structure to assure it can support the additional weight of a new level. He must also study how the roof ties into the walls and take appropriate measures to assure they can remain standing while the roof is off.
Another common mistake is to replace original windows on the assumption modern windows are more energy efficient. In fact, the biggest energy loss from windows is caused by poorly operating moving parts or by gaps between the window frame and the surrounding stone. If existing windows can be made to operate correctly and fit properly, they should be restored, just like the rest of the building.
Not doing enough
Repairing water damage without resolving the root cause is another example of not doing enough. Contractors need to evaluate the rain gutters, downspouts and window flashings to assure they are directing water away from the masonry.
When repairing or maintaining historic structures, it is critical to take the extra steps required to get it right the first time. The National Park Service publishes a series of bulletins on correct methods for caring for historic masonry buildings at www.nps.gov/tps/how-to-preserve/briefs.htm. In addition, working with architects, preservationists and contractors experienced in masonry restoration can help you avoid costly mistakes and irreparable damage to your building.
Rhonda Maas is the co-founder and president of Building Restoration Specialties Inc. (BRS), which specializes in masonry restoration, preservation and conservation of historic buildings. Founded in 1986, BRS has a bonding capacity of about $7 million, and is positioned to handle projects ranging from $2,000 to more than $2 million. Learn more at www.brsrestores.com.
|Last Updated on Tuesday, 03 September 2013 18:56|