Thornoaks Local Historic District Design Guide. Washtenaw County Historic District Commission September 2018

Transcription

1 Thornoaks Local Historic District Design Guide Washtenaw County Historic District Commission September 2018

2 Introduction Why Thornoaks? The Thornoaks neighborhood was designed and constructed in the late 1950s and 1960s. It is a wonderful example of a Post-World II Single Family Residential Development and Mid-Century Modern architecture, and contains significant architectural contributions by important local architects, specifically James H. Livingston. Thornoaks was designated as a Washtenaw County Local Historic District (LHD) in April 2018 in an effort to preserve the unique Mid-Century Modern neighborhood. The historic district contains 31 houses and three vacant lots. What does designation mean for property owners? As a LHD, any changes beyond ordinary maintenance to the exterior of properties or landscape, and any additions, alterations, or new construction, must be reviewed by the Washtenaw County Historic District Commission (WCHDC) before any work is started on the project. You can find the Application for Work and additional resources on our website, at The WCHDC reviews each proposed project based on guidelines called the Secretary of the Interior s Standards for Rehabilitation. The HDC uses these Standards to determine if a project maintains the historic character of the historic district. You can find a copy of the Secretary of the Interior s Standards for Rehabilitation at the end of this guide. Thornoaks Local Historic District Design Guide We hope this guide will help homeowners navigate preserving the integrity of the historic district while completing necessary alterations or additions to their property. The guide will help homeowners plan exterior renovations and guide any new construction, as well as assist the WCHDC review applications for appropriateness of exterior changes or new construction. This design guide supports the Secretary of the Interior s Standards for Rehabilitation, but does not replace the Standards. The Standards remain the basis for all HDC decisions. All HDC decisions will be decided on a case-by-case basis, taking into account the unique situation of every application. What features are important to preserve? In Thornoaks, Livingston developed a singular aesthetic tone for the neighborhood. Through the Planning Committee that oversaw construction, homes in Thornoaks expressed varying levels of Mid-Century Modern design features. The Planning Committee sought to ensure a unified, though not uniform, aesthetic vernacular for the neighborhood and ensure harmony of external design with the external structure and surrounding landscape. These external and landscape features are what make Thornoaks special. 2

3 Important Exterior Features Important exterior features are recognizable across the neighborhood and include: simple, modular, rectangular and horizontal elements; flat or low sloped roofs; gable end roofs with under-the-gable-windows; broad overhangs; exposed exterior beams or rafters; large floor-toceiling windows that offer wide views of the surrounding landscape; use of simple/natural materials like wood, brick, concrete and concrete block; aluminum or wood windows; unobtrusive decks and patios with low-profile railings, and unadorned exterior elevations. Gable end roof with under-the-gable windows and a broad overhang Low sloped roof Flat roof Floor-to-ceiling windows Advertisement from House and Home, January 1955 Unobtrusive patio 3

4 Relationship with Surrounding Landscape Additionally, the properties have an intimate relationship to the landscape and topography of the neighborhood. The Planning Committee ensured that structures were thoughtfully sited to take full advantage of views and use of South Pond, the Huron River, and/or the rolling, secluded wooded areas. Obstructive walls and fences were required to obtain approval so as to not unnecessarily obstruct views or viewsheds. Today, the neighborhood maintains an open, rolling topography unmarred by boundary line fence or walls. Drawing from House and Home, January 1961 Ann Arbor Charter Township Ordinance No requires a Tree/Woodland Removal Permit that can be found on their website: 4

5 How do I start planning a project for my property with preservation in mind? Before homeowners begin planning exterior renovations or new construction, a few questions can help determine the best approach to upcoming work. 1. What are the significant characteristics of your home? What from the previouslymentioned list contributes to your home and property? 2. What is compatible with your home s architecture? This is especially important when planning additions, or major alterations. Additions should be sensitive to the characterdefining features of a house. 3. What are the characteristics of surrounding historic homes? This question is especially helpful if you live in a home that isn t historic, or if you are building a new home on an empty lot within the neighborhood. Renovations will look different depending on your home and property. This pamphlet will explore four topics: 1. Rehabilitating existing homes 2. Additions to historic homes 3. New construction 4. Demolition 5

6 Existing Homes: Think Rehabilitation Rehabilitation means preserving and retaining the historic character of a property, including the defining characteristics and its historic purpose. Within a historic district, rehabilitation balances needed alterations and retaining historic character. There are three forms of rehabilitation: 1. Preserve: Preserving means maintaining the historic style, form, materials, and footprint of your property. This only applies to historic materials that still exist, and does not apply to alterations that don t reflect the original historic house. Strive to maintain and care for these character-defining features. 2. Repair: If historic features are damaged, repair them using similar materials, design, and finish. 3. Replace: If repair is not possible, replace the historically-significant features with compatible materials based on research, or materials that complement the historic structure. For a more detailed explanation of rehabilitation, see the National Park Service standards available online at The following pages will consider rehabilitation of specific aspects of the home: 1. Site Design 2. Roof 3. Siding 4. Windows 5. Doors 6. Porches 7. Car Ports/Garages 8. Utilities and Mechanical 9. Sustainability 6

7 Site Design: A quick drive through Thornoaks reveals the special relationship between each house and the gently rolling landscape. Many of the properties on the south end of the neighborhood either have direct access to and views of South Pond and the Huron River, or are located on a rise with views of South Pond and the Huron River. Properties on the north side of the neighborhood are situated with views of a steep ravine and a meandering creek. Properties located in the interior of the neighborhood are situated to take advantage of the rolling, secluded, wooded areas. All the contributing properties are sited with an intent to interact with the landscape. The thoughtful placement of the properties within the landscape is integral to the overall neighborhood aesthetic. When planning renovations, keep in mind this special relationship with the surrounding land. Topography: Avoid changing the topography through grading, filling, terraces, or excavating. Landscaping: Preserve the mature and natural landscape features. Landscaping should complement the rolling hills and natural feel of the area. Screens: Mid-Century houses often included decorative screens to shield home entrances from view. Strive to maintain these features. Retaining walls: Retaining walls, when needed, are constructed of natural materials or concrete. Materials should match the house and blend with the landscape. Fences: The rolling landscape of Thornoaks is enhanced when unbroken by fences. However, fences are sometimes necessary. Fences should blend with the landscape and complement the house. They should be made of natural materials and have a simple design. Decks and Patios: Decks, patios, and associated low-profile railings should be unobtrusive and connect the interior and exterior spaces. Sheds: Sheds should be unobtrusive and located behind the house. Sheds should take into consideration the form, color, and materials of the house and/or garage. Driveways: Driveways in Thornoaks were also designed with landscape in mind. Strive to maintain the original footprint and width integrated with natural landscaping. Maintain simple materials. New driveways should also integrate with the natural landscaping. 7

8 Wood screen providing privacy to bedrooms Simple retaining wall Illustration of the front facade of a home model from House and Home, January 1953 Wooden fence Simple patio Simple retaining wall Illustration of the rear elevation of a home model from House and Home, January

9 Roof: Types: A variety of low-pitched roof types are located in Thornoaks, including flat roofs, low-pitched gabled roofs and a combination of the two. Original roof type and slope should be maintained. Overhangs: Houses have a variety of eave depth, from a shallow overhang to quite deep. The original overhang should be maintained. Exposed Rafters: Many houses have exposed rafters beneath the overhang. These should remain exposed. Roof Materials: If the original roof had special shingle materials, such as cedar shakes, replacement in-kind is encouraged. Typical shingles such as asphalt or fiberglass are appropriate for gabled roofs. Flat roof materials include rolled or membrane roofing. Chimney: Mid-Century chimneys are a key component of house design. Mid-Century chimneys have wide, massive, low, and rectangular footprints with natural facing such as stone or brick. Chimney repair should maintain original materials, or replace in-kind when needed. New chimneys should be consistent with typical Mid-Century chimney design. Cedar shake shingles Low-pitched roof Wide, low, rectangular chimney Overhanging eave Exposed rafters Advertisement from House and Home, January

10 Siding/exterior finishes: Siding in Thornoaks consists of a mix of natural materials, including: Vertical and horizontal wood siding, board and batten wood siding, yellow and tan brick, sandstone, uncoursed multicolored stone, and concrete. Vertical wood siding Board and batten Horizontal wood siding Vertical wood siding Yellow/tan brick Sandstone Uncoursed stone Concrete Original siding should be maintained, repaired, or replaced with appropriate materials and should not be covered. Wood siding should be painted an earth-tone hue such as brown or tan as is typical in the neighborhood. Original masonry should be gently cleaned and should not be sandblasted. Necessary replacement siding should complement original siding. 10

11 Windows: Windows are an integral part of Mid-Century design. Houses in Thornoaks have a variety of window types, including floor-to-ceiling plate glass windows, window-walls, under-the-gable windows, as well as rectangular double-hung windows, sliding windows, casement windows, and jalousie windows. Original window materials are often aluminum, wood, or steel. Maintaining original windows is preferred, as windows have a large impact on the facade of a house. Regular maintenance and the installation of storm windows can help extend the functionality of original windows. Also, a deteriorated plate glass window may require only a replacement pane along with existing frame maintenance. Window replacement is strongly discouraged on the front facade of a house. However, if materials are so deteriorated that they require replacement, replacement windows should match shape and size, pattern, dimensions, materials, and operability of original windows. For example, a jalousie window could possibly be replaced with an awning window of the same dimensions. (See note on jalousie windows) Adequate replacement materials include wood and wood-composite, aluminum and aluminumclad, steel, and fiberglass. Vinyl is not permitted. Storm windows should mimic existing sashes and should not obscure or damage the existing window frame. Casement window Under-the-gable windows Floor-to-ceiling plate glass windows Illustrations and photograph from House and Home, January 1955 Double-hung window Sliding window Jalousie window Awning window Illustrations from House and Home, January 1961; and Retro Renovation; 11

12 A note on jalousie windows: Originally designed for warmer areas such as Florida, the jalousie window made its way north with mid-century modern architecture. Even well-maintained jalousie windows can be drafty in the winter. We recommend installing interior or exterior storm windows during cold seasons. When deteriorated, these windows are very inefficient. When replacement is required, there are a few options available to consider, including replacement with a similar window, such as an awning window, or replacement with a new jalousie window. Several companies still manufacture jalousie windows. Here is a list of a few manufactures: 1. Tafco Jalousie Widows 2. Breezeway Louvered Windows 3. The Burch Company New jalousie windows can also benefit from storm windows installed during cold season. Doors: Much like windows, doors are important to the design of a Mid-Century home. Original openings should be maintained. Original doors should be maintained if possible, but if replacement is required, the door should match the original door or be compatible with the Mid-Century style of the home. Common original doors include sliding doors, louvered doors, plain wooden doors, and wooden doors with simple lights (windows). Louvered door Sliding door Plain wood door Wood doors with simple lights Illustrations from House and Home, January 1953 and January

13 Porches: Mid-Century porches in Thornoaks are simple. In many instances, the front entrance is simply recessed for greater privacy, sometimes with a small overhang, and sometimes with simple posts supporting the porch roof. Often the front entrance is flush with the facade and covered by a deep eave overhang spanning the entire facade. The simplicity and privacy of these entrances should be maintained and should not be obscured. Home owners should not construct new porches or expand current porches. If porch post or railing replacements are necessary, use materials compatible with original materials. If it is necessary to add new posts or railings, use materials compatible with the house such as wood, aluminum, or iron. Porch covering incorporated into eave overhang Illustrations from House and Home, January 1953 and January

14 Garage and Carport: Mid-Century architecture was designed for families with automobiles. Carports or garages were designed to complement the house but remain simple and understated. In Thornoaks, most houses have a simple one-or two-car carport. Some are completely open and others have a few walls. The roofline of each carport complements that of the main house; they are often flat, and sometimes angled to reflect a gabled roof. These carports are an important part of Thornoaks architecture, and should be maintained. Some Thornoaks homes were designed with garages. Some are incorporated into the lower level of the house, while others flank the house with complementary architecture and roofline. These garages should be maintained. If replacement construction is necessary, it should use architectural elements that complement the home including siding and roof shape and pitch, and follow the original footprint of any previous carport or garage. If new garage construction is necessary, it should also use architectural elements that complement the home, be unobtrusive, and be set back from the house. It should not be larger than two bays, in keeping with typical neighborhood garage size. Photograph of home with a carport in Sarasota, Fl. from House and Home, January 1955 Illustration of home with garage in Los Angeles, Ca. from House and Home, January

15 Utilities and Mechanical Systems: New utilities such as air conditioning, satellite dishes or antennas, venting, or other equipment, are useful and sometimes necessary when updating a historic home. However, these new items can detract from a home s historic exterior, and should be located in inconspicuous places such as a side or rear elevation, away from public view. Decorative screens, fencing, and vegetation can also shield new systems from view. Sustainability: Preserving already-constructed homes is a sustainable practice. It saves the energy of demolition, processing and manufacturing materials, transportation costs, and construction costs. However, taking further steps to make sustainable choices is encouraged. When researching renewable energy, keep these guidelines in mind: Solar and wind energy should be hidden from public view; either in a side or back yard, or flush with the roofline. Take the natural setting into account when planning the location of wind or solar energy options, and plan accordingly. Additional resources: Solar Panels on Historic Resources, National Parks Service 15

16 Additions to Existing Homes Sometimes additions to your home are necessary. When building in a historic district, a few guidelines will make sure your addition does not adversely affect the district. Though the addition should be compatible with the original house, it is important to remember the addition should be recognizable as a product of its own time, and not mistaken for an original feature. Take note of the common materials and massing within the neighborhood discussed above when planning your addition. The addition should reflect the original home s scale, form, massing, and materials. The addition should not overwhelm the original structure. In other words, it should not be taller or wider than the original structure. The height of the new addition should relate to the main structure and to its surroundings. The addition should maintain the relationship between the house and the surrounding environment and the street. The addition should be set back from the main mass of the building. It is preferable to locate the addition behind the main mass of the original building. The addition should use compatible rooflines, windows, and materials in a way that complements, but does not mimic, the original house. This could be done with stylized ornamentation. 16

17 New Construction There are several empty lots in the Thornoaks neighborhood. These guidelines outline a few principles to aid builders. Property owners must submit an application to the WCHDC prior to the start of any work. First and foremost, new construction should take into account the size, scale, massing, and style of the rest of the neighborhood. New construction should be compatible with the historic homes of Thornoaks, but a product of its own time, and not mistaken for a historic property. New construction should respect the homes on either side, and not dominate the streetscape with inappropriate massing. Take note of the common materials and massing within the neighborhood discussed in this document when planning your new construction. Site: Match the setback to those of nearby houses. Alter the topography of the lot as little as possible, incorporating landscape features into planning and minimizing grading changes. Scale: The overall height, foundation height, and floor-to-ceiling height should be compatible with neighboring houses. Roofline: The roofline should be compatible with those in the neighborhood: low-pitched gables or flat roofs, or a combination of both. Windows: Windows should share similar size and shape to others in the neighborhood. Windows are generally rectangular in shape and a variety of sizes. Options include floor-toceiling plate glass windows, under-the-gable windows, double-hung windows, sliding windows, casement windows, and awning windows. Materials: Use natural materials and colors for siding, chimney, and retaining walls. Features: Stylized features compatible with historic structures could include recessed entries, low, massive chimneys, and other simple details. Demolition The demolition of any resource in the Thornoaks Historic District would be an irreplaceable loss to the historic district and the community. The demolition of a resource within the historic district must always be the last resort, and the property owner must demonstrate adequate reason to the WCHDC for demolition or the application will be denied. A Demolition Permit Application must be submitted to and approved by the WCHDC before demolition occurs. The Demolition Permit Application will be available by request and on the WCHDC website at 17

18 To Learn More To learn more about the WCHDC, see our website at If you have questions about the historic district or the Application for Work, contact WCHDC staff Melinda Schmidt at or Consulted Works City of Miami Historic and Environmental Preservation Board, City of Miami Historic Design Guidelines. Historic District Committee of the Parkwood Garden Club. Parkwood Historic District Design Guides. House and Home, January US Modernist. House and Home, January US Modernist. House and Home, January US Modernist. Kirkwood Landmarks Commission. Mid-Century Modern Barrett Brae Design Guidelines. 20Guidelines% pdf. National Park Service. Creating and Using Design Guidelines. National Park Service. Secretary s Standards for Rehabilitation. Retro Renovation, Jalousie windows, their history and where to buy them today 21 photos from Washtenaw County Historic District Commission. Thornoaks Neighborhood Study Committee Report. Neighborhood-Study-Committee-Report-PDF. 18

19 The Secretary of the Interior s Standards for Rehabilitation 1. A property shall be used for its historic purpose or be placed in a new use that requires minimal change to the defining characteristics of the building and its site and environment. 2. The historic character of a property shall be retained and preserved. The removal of historic materials or alteration of features and spaces that characterize a property shall be avoided. 3. Each property shall be recognized as a physical record of its time, place, and use. Changes that create a false sense of historical development, such as adding conjectural features or architectural elements from other buildings, shall not be undertaken. 4. Most properties change over time; those changes that have acquired historic significance in their own right shall be retained and preserved. 5. Distinctive features, finishes, and construction techniques or examples of craftsmanship that characterize a historic property shall be preserved. 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials. Replacement of missing features shall be substantiated by documentary, physical, or pictorial evidence. 7. Chemical or physical treatments, such as sandblasting, that cause damage to historic materials shall not be used. The surface cleaning of structures, if appropriate, shall be undertaken using the gentlest means possible. 8. Significant archeological resources affected by a project shall be protected and preserved. If such resources must be disturbed, mitigation measures shall be undertaken. 9. New additions, exterior alterations, or related new construction shall not destroy historic materials that characterize the property. The new work shall be differentiated from the old and shall be compatible with the massing, size, scale, and architectural features to protect the historic integrity of the property and its environment. 10. New additions and adjacent or related new construction shall be undertaken in such a manner that if removed in the future, the essential form and integrity of the historic property and its environment would be unimpaired. 19