the effects of herbicide on stone and masonry

The Effects of Herbicide on Stone and MasonryNational Center for Preservation Technology and Training

Caitlin Oshida, Debbie Smith and Mary Striegel, Ph.D.

Brick26%

Concrete12%

Sandstone9%

Limestone15%

Marble6%

Granite15%

Other17%

Historic Feature Materials

Roundup® (G-

lyphosate)58%

Vanquish® (Dicamba)

1%

Garlon 4® (Triclopyr)

22%

Arsenal® (I-mazapyr)

1%Other18%

Types of Herbicides Used

Survey Results Collected From

National Park Service Sites

Types of Historic Features

House Outbuilding Fort Monument Cemetery Other0

10

20

30

40

50

60Historic Features

Yes No0

20

40

60

80

100

Are Herbicides Used To Re-move Unwanted Vegetation?

Responses

Experimental DesignPotential Effects

• Roundup®• Garlon 4®

• Salt crystallization (efflorescence) • Discoloration• Change in pH• Pitting/change in surface• Accelerated deterioration

Preliminary test brick samples before (left) and after (right) being submerged in Roundup® herbicide for 24 hours and dried for 24 hours; visible signs of efflorescence.

Purpose

• Brick• Limestone

• Granite• Concrete

Historic Materials

Herbicides

Far right: Chiseling out concrete samples. Right: Bottle of Roundup® that can be bought at the local store.

Response #

Response #

When herbicide is applied to vegetation close to historic structures, some of the herbicide will come into contact with the feature. Based on this study, an experiment has been developed that will test the effects of herbicide on historic stone and masonry material. Far left: Spray

application of herbicide near a building. Left: Dyed herbicide shows where it actually ends up on the structure.

Photo courtesy of Jason Church