Home | Subscribe
Hawk & Trowel Archives
March 2008

Preservation Plasterer: Maintenance helps preserve buildings...and saves money

by Rory Brennan

Essentially, maintenance is the insertion of small amounts of capital into a building over an extended time frame. When you own a building, these steps are undertaken to preserve the equity that you have invested in your architecture. There are inspections, adjustments, cleanings or replacements that should be done regularly to ensure proper functioning of all the systems in a house and to avoid costly emergencies. Maintenance is a continuing process. This is what the preservation movement is all about.

To maintain a building's structural and elemental integrity, materials are replaced only as necessary. The embodied energy within the existing building's materials gives credence to the philosophy that keeping the original material in place as long as possible is the best economic choice.

When it becomes necessary to replace the original building, the choice of replacement materials is the paramount factor affecting the longevity of the repair and the preservation of your home.

About now you're wondering what this has to do with plaster. Over the past 30 years there have been a couple of times I've been asked to repair the plaster in a building, which I did, only to be called back to fix my repair. It always turned out there was a reason for the continued damage that related to a choice in repair or maintenance materials prior to my showing up at the building.

An example will illustrate the true cost of deferred maintenance. The example: a roof leak.

During the 103-year life span of a building, there was a cycle of repeated damage and repairs. My project was to address a water leak in this building during the winter.

In New England we have a condition called ice dams. This condition occurs when a building is insulated with, in this case, blown-in insulation. The weak spot in most insulation jobs on historic structures is the ventilation of the eaves, where the insulation is missed and the building's heat is allowed to escape.

The second condition, for this building, was that the slate roof was replaced with asphalt shingles. One of the properties of slate roofs - besides being rock, and therefore very durable and easy to maintain - is that snow and ice slide off them with incredible ease. Asphalt shingles keep the snow in place.

Ice dams are formed when the escaping heat melts the snow at the eaves of the roof. The water then runs to the edge of the roof and freezes. After a number of freeze cycles a sizable dam of ice was built up and a pool of water was backed up behind it, eventually deep enough to run under the shingles and leak into the building in what can only be called a flood.

These conditions resulted in substantial damage to the plaster. Repeatedly. Since those choices were made, the plaster had been repaired a number of times, all with varying degrees of success.

The roof was replaced with asphalt shingles for two reasons: There was no one who knew how to fix the slate when it was in need of maintenance, and asphalt shingles were less expensive.

The building walls were insulated with blown-in insulation to save money during the 1970s. Insulating the walls of your historic building will save you somewhere around 10 percent on your heating bill if it is done correctly.

The plaster repair was done with modern bagged gypsum plaster, which, when it so much as looks at water, falls apart. Had the repair been done with a lime plaster like what originally had been used, the repairs and what was left of the original plaster would have been more durable in the face of the water infiltration from the current round of ice dams.

Problems started to show up as plaster damage. I found evidence of at least four plaster repairs, all with the wrong choice of materials. This round of repairs that started in the 1970s with two "unrelated choices" will cost the owners of this building in excess of $16,000. I don't know how much the last three repair cycles cost. Additionally, water filtering down through the building's infrastructure will cause slow damage from dry rot, among other things. Did insurance pay for the damage? Yes and no. There is never enough compensation for the long-term damage done to a building in the name of repair.

Maintenance that protects the building from damage is ultimately less expensive than repairs when water pours in.

A second example of the cost of deferred maintenance is a house that had a dry-laid brick patio. The bricks were laid in a bed of sand over a gravel base. This was too difficult to maintain. The bricks were pulled up, a gravel base laid down and a 4-inch pad of concrete poured over the gravel up to the terra-cotta block from which the house was made. The bricks were hard-mortared into place.

I was called in when the exterior render showed signs of falling off. I went up and repaired the stucco. The next year I was called to task because the stucco had fallen off just like the previous repair. I had a meeting with the architect, the contractor and the owner. We reviewed the drawings, and I pointed out the concrete pad was pulling moisture out of the ground and conveying it to the terra-cotta block. The stucco wasn't failing - the terra-cotta block under it was rotting and falling to pieces. This condition was created in the name of "maintenance-free" and will cost a considerable sum to rectify. Postscript: Two years later, the "friends" of this historic house called me to come and fix the stucco, as they had just raised the funds necessary to "restore" it. My first question to them was, "Did you undertake the moisture remediation recommendations I gave you two years previously?" Their answer was no, so I suggested they take the funds and do the moisture remediation as part of their maintenance plan. Then I would be happy to come and fix their stucco so it would stay fixed. I haven't heard from them.

Whether an incorrect choice of materials or a situation of deferred maintenance, the cost for these choices continues for years beyond when the initial choice was made. Both of these choices increase the cost of keeping a building usable.

This is a hard way to "save money" and points to the importance of having trained craftspeople who know the building and the material it's made from design a maintenance program.

Modern-building knowledge does not translate directly into knowledge about historic buildings, and in many cases, as was illustrated by these examples, it is detrimental to a building that for most of us represents our largest equity stake in the world.

This illustrates the need for adequate training programs in the modern-building trades that stress the importance of having people trained in developing maintenance plans for historic buildings.

When well-intentioned previous owners do not maintain their building, the next owner is stuck with all those years of wrong material and installation choices, as well as maintenance items that are coming due during his or her custodianship of the home. These are the things that drive the price of "restoration" up.

Maintenance is using the proper materials and techniques to achieve the longest-lasting repair, and in the long run, it results in the least expensive option for owners of older homes.

Archives: The Preservation Plasterer
Spring 2009
How to Repair Historic Plaster
by Rory Brennan

Rory Brennan has spent the last 27 years focusing on the repair of pre-1940 plaster, both flat and ornamental. He is a pioneer in the use of adhesives to stabilize existing plaster and the use of traditional materials in repair. Rory's current endeavor is Big Wally's Plaster Magic, www.plastermagic.com. He can be reached at rbrennan@plastermagic.com.

The Plaster Zone >
Ornamental considerations
by Robin Raymer

The Preservation Plasterer >
How to repair historic plaster
by Rory Brennan

That Drywall Guy >
Building the best arches and curves
by Myron Ferguson