Paving, Retaining Walls, Garden Structures and Landscaping

  1. Topic: Paving, Retaining Walls, Garden Structures and Landscaping

  2. Definitions:

    For purposes of these guidelines,

    1. Paving includes any structure or material, not integral to any building, used as surface material for walks, drives or other surfaced areas.
    2. Retaining walls include walls or other structures used to retain soils or other materials adjacent to driveways, sidewalks, and property lines. Retaining structures which present no more than nine (9) inches of vertical exposure (such as may be used within a garden layout) are not reviewed unless Commission staff determines that they will have a significant visual impact as seen from the street or neighboring properties.
    3. Garden structures include open structures which are not secured to permanent footings (below the frost line), such as open play equipment, open gazebos, arbors and trellises, fountains and bird baths, sculpture or other art works. A structure is not considered a garden structure if it has one or more of the following characteristics:
      1. attached to permanent footings
      2. with solid, glassed, or screened walls, and larger than 50 square feet (such as garages, garden sheds)
      3. attached to the principal structure on the property

      For structures with the above characteristics, review is required. See Guidelines for Porches, Infill Development, and Fences which may apply, as well as the Secretary of the Interior’s Standards.

      Garden structures will not be reviewed unless Commission staff determines that they have a significant visual impact as seen from the street or neighboring properties. If there may be a significant visual impact, the project should be discussed with Commission staff to determine whether review is required.

    4. Landscaping includes the movement and contouring of soils, use of paving and retaining walls and the placement of plantings at a property.

    The Commission will review landscaping proposals to the extent that they involve a significant change in the contouring and elevations of a property or incorporate the use of paving and retaining walls. The Commission does not review the selection, placement or movement of plantings. The Commission will, however, consider the use of plantings where they impact on other work, such as the use of plantings to obscure a new feature, basement windows, or utility equipment.

  3. Policy

    The Secretary of the Interior’s Standards for Rehabilitation and Guidelines for Rehabilitating Historic Buildings recommended:

    “Retaining the historic relationship between buildings, landscape features, and open space.”

    [Landscape features include landforms and designed grades; walkways, driveways, retaining walls, curbs and edge walls, site structures, furnishings and objects, and plantings.]

    The Secretary of the Interior’s Standards for Rehabilitation and Guidelines for Rehabilitating Historic Buildings recommended against:

    “Introducing any new building, streetscape or landscape feature that is out of scale or otherwise inappropriate to the setting’s historic character.”

    “Introducing a new landscape feature or plant material that is visually incompatible with the site or destroys site patterns or vistas.”

    The Secretary of the Interior’s Draft Guidelines for the Treatment of Historic Landscapes recommended:

    “Preserving natural landforms and designed grades through routine maintenance.”

    “Preserving historic curbs, edge walls or other edge materials during resurfacing by maintaining the historic height or finish elevation of the road or path grade.”

    “Inventorying and documenting the existing conditions of:

    Site furnishing and objects such as benches, lights, fixtures, signs, drinking fountains, trash receptacles, fences, tree grates, clocks, flagpoles, sculpture, monuments, memorials, planters, and urns and their materials such as metal, stone, masonry, or wood.”

    Landscape structures such as walls, terraces, arbors, gazebos, follies, stadiums, tennis courts, playground equipment, plazas, greenhouses, cold frames, steps, bridges, and dams.”

    The following guidelines concerning paving, retaining walls and garden structures are provided to assist in interpreting and applying the Secretary of the Interior’s Standards and Guidelines.

    As with other alterations to the exteriors of landmarks and buildings within the historic districts, the introduction of paving, retaining walls or garden structures, or changes thereto, must be reviewed by the Commission or its staff as indicated in the definitions above. Often these features are not new, but repairs or replacements are in question. The introduction of new paving, retaining walls or garden structures will require closer review than a repair or change in materials of existing features. The Commission of its staff will review each proposal on its individual merits. The existence of other historically inconsistent work in the area is not a basis for approval of another inconsistent feature.

  4. Guidelines

    1. Location

      The proposed location of a new feature is important. Paving or retaining walls placed in rear yards where visibility from the street is limited will require less stringent review than similar features at the front of the property. Garden structures are defined above, if placed in the rear yard, do not require review. If placed in front or side yards, they will require review only if Commission staff determines that they would have a significant visual impact from the street or neighboring properties. Owners should consult with Commission staff to determine whether an application should be submitted. Solid, large permanent structures, or those attached to the main structure do require review (see the definitions above).

      One common paving feature in front yards is the driveway and curb cut. “Radius” type curb cuts are historically appropriate and are typical in all the historic districts. Blocks or neighborhoods with consistent use of the “radius” curb cuts are not only more historically appropriate but also provide additional space for on-street parking. The wider, “flare” curb cut is found in more recently developed areas with wider lots. (Often crews replacing curb cuts will expect to use the flare style unless directed to maintain the radius style.)

      Retaining walls are generally utilitarian structures which vary significantly in style and material. The most frequently used are along sidewalks, driveways or property boundaries where there is a change in grade. The historic contours and changes of grade and their relation to the structures should not be significantly changed without good reason.

    2. Design and Materials

      Paving and retaining wall proposals should be consistent in design, materials, and scale with historic features. For paving, simple scored concrete, stone, paving brick or other historic materials are recommended over concrete block, asphalt, or exposed aggregated or other modern concrete treatments. Where a particular material or style is documented or evident in the existing surface, it should be maintained if possible.

      Styles and materials of retaining walls generally followed the style and material of the main structure or its foundation, although this varied somewhat with the period and the original cost of the structure. For retaining walls, concrete, stone, brick or other historic materials are recommended over concrete block, treated wood, railroad ties, metal or other contemporary materials. Walls sometimes reflected the style of the main structure, but often were unadorned and utilitarian. Earlier versions were often constructed of cut stone or brick. Later, concrete become the most common material.

      The physical evidence of even a deteriorated wall can often give an indication of the original style and material. When the Commission agrees that repair or reconstruction in the original materials is impractical, simple designs consistent with historic types are recommended over more contemporary methods. Size and scale of the features will be considered closely.

    3. Other Regulations

      In all cases, zoning, traffic engineering or other codes and agencies should be consulted by the applicant.

    These guidelines were approved by the Michigan Bureau of History as of February 19, 1997 pursuant to Section 5.(3) of Act 169 of 1970, as amended (Local Historic Districts Act).


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