The PMR Blog
Help! There's a Small Forest on My Building!
Posted 2012-02-28 by Bob Neas in Mortar

Mosses, vines, and even trees can start growing on your historic buildings. How does this happen? Biological growth appears when there’s the presence of moisture on the structure, especially in shady or woodsy settings. Often moisture problems and biological growth is found on the northern side of buildings because that area doesn’t receive as much sunlight, resulting in less water evaporation and overall damper conditions. If the plant growth is especially extensive you may not be able to treat or remove the vegetation due to wildlife laws and acts that are in place. The problem with biological growth is it can damage the building’s structure, cause further moisture and water problems, and completely take over your building. How can you get rid of plant growth on your historic building? And how can I keep biological growth from coming back? If I didn’t want to get rid of the all the vines and mosses on my building, how can I at least keep it in check? This article will answer this question and others.

How can you get rid of plant growth on your masonry building? First have the extent of the biological growth assessed. An expert should be able to tell you these things: Will physically removing the vegetation damage the masonry? What is the source or cause of the moisture problem and biological growth? What is the best method to remove the plant growth?

With shrubbery and vines it’s important to pre-treat the vegetation before physically removing it, this can reduce your chances of also pulling out the masonry it’s attached to. By completely removing the roots, this will greatly reduce the chances of the problem growing back but before doing this you need to chemically treat the roots to kill off the plant so its grasp on your historic building loosens. Ivy and vines in particular can cause many problems when it pervades the masonry façade’s joints or cracks displacing or pushing brick and stone out and detaching it from the structure. Another problem is ivy commonly leaves behind an imprint or scar on the masonry surface that can be very difficult to remove.

Another culprit of added water problems is moss, because mosses hold moisture and can prevent water evaporation. Moss thrives in wooded cooler climates. Relatively easy to detach, moss can be difficult to prevent because as was mentioned, it’s usually found in cool damp climates and unless you plan on moving your entire building, preventative measures will need to be taken. There are many chemical herbicides that can be utilized.

What do I need to know about microbial treatments and herbicides? Chemically treating historic masonry is one of the best preventative measures for biological growth. It’s important to consult a specialist though, because herbicides can be dangerous for surrounding wildlife and plant life. An expert will know how to properly handle chemicals and equipment safely and protect the masonry and nearby wildlife.

Many people feel that a little bit of vegetation on a historic masonry building adds to the character and ambience. Ivy and mosses are commonly the types of growth that building owners opt to preserve on their historic masonry building. The best way to preserve your masonry and keep the vines is to install a trellis or some sort of lattice-work that is slightly spaced from the actual masonry wall. This decorative wall needs to be frequently pruned and maintained to keep it from growing onto the masonry or getting out of hand.

Biological growth is frequently found on historic masonry. Whether you decide to remove it completely or keep a little bit of plant growth on your building, it’s always good to talk to masonry professional.

If you live in Philadelphia, PA, NJ, or DE contact us to discuss biological growth or water problems your building may be experiencing.

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