top of page


Chapter 10 Commercial Rehabilitation: Welcome
Chapter 10 Commercial Rehabilitation: Text


These Commercial Rehabilitation Guidelines are intended for the use of commercial property owners planning work on contributing structures or sites within the HPOZ. Contributing structures are those structures, landscapes, natural features, or sites identified as contributing in the Historic Resources Survey for this HPOZ. Generally, “Contributing” structures will have been built within the historic period of significance of the HPOZ, and will retain features that identify it as belonging to that period. The historic period of significance of the HPOZ is 1887 to 1951, the time period in which the majority of construction in the area occurred. In some instances, structures that are compatible with the architecture of that period or that are historic in their own right, but were built outside of the period of significance of the district, will also be “Contributing”.

The Commercial Rehabilitation section of the guidelines should be used in planning and reviewing projects involving structures in commercially zoned areas. In addition to commercial and institutional buildings, the Guidelines will also address structures that were originally built as commercial structures which have since been converted to residential use as well as structures that were originally built as residential structures that have been converted to commercial use. For instance, the Commercial Rehabilitation Guidelines would be used to plan work to a historic structure built as for shops and offices that is now used as residential lofts. This chapter also contains guidelines for projects that may be exempt from review all together (such as some landscape projects), but are included to assist the user in executing a project that will be compatible with the HPOZ as a whole. Additionally, the guidelines in this chapter may also be of use to owners of Non- Contributing sites who wish to execute restoration or reconstruction projects of their own accord.

The Commercial Rehabilitation Guidelines are divided up into eight sections, each of which discusses an element of the design of historic structures and sites. If you are thinking about planning a project that involves the area around your building, such as parking areas, the “Site Design” section, might be a good place to start. If you are planning work on your roof, you might want to look both at the architectural styles section to determine the style of the building, and then at the “Roofs” section of these guidelines. The Table of Contents details other sections that might pertain to your project.

While the Design Guidelines throughout this Preservation Plan are a helpful tool for most projects, some types of work may not specifically be discussed here. With this in mind, it is always appropriate to remember that the Design Guidelines of this Preservation Plan have been developed in concert with the Secretary of the Interior’s Standards for Rehabilitation, a set of standards used nationally for the review of projects at historic sites and districts. All projects should comply with the Secretary of Interior’s Standards, and where more specific guidelines have been set for by this Preservation Plan, the guidelines herein.

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 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.

Chapter 10 Commercial Rehabilitation: About


The design of the site of an historic structure is an essential part of its character. This design includes the streetscape in which the site is set; any features such along the street such as street furniture or planting strips; the way a structure sits on its lot in relation to other structures and the street; and landscaping elements. While many of the historic structures in the HPOZ may have lost some of these characteristics over time, certain common characteristics remain which help to de fine the character of these historic areas and the structures within them.

Historically, commercial areas in Los Angeles were characterized by a consistent setback usually aligned against the sidewalk. This alignment provides for a comfortable and inviting pedestrian thoroughfare. Parking was located either to the rear of buildings or was provided on the side of the street. Preservation of this regular street wall is essential to maintaining the historic, pedestrian-friendly character of our historic commercial areas. Preservation of the historic placement of a structure against the sidewalk, with parking provided on the street or to the rear provides an inviting pedestrian experience for residents and other customers, and helps to preserve or enhance the character of a neighborhood. Any plans for alteration of the footprint of an historic commercial structure should be carefully considered to preserve this relationship between the buildings and the street.


1. Mature trees and hedges, particularly street trees in the public planting strip, should be preserved whenever possible. When removal of street trees is necessary, trees should be replaced with other mature, shade producing trees that are consistent with historic planting patterns.

2. Historic sidewalk features should be preserved wherever possible. Special attention should be paid to pavement score patterns and texture, as well as to street furniture such as trash receptacles and light posts.

3. Parking areas and driveways should be located to the rear of commercial structures.

4. Tree planting should be dispersed throughout surface parking areas so as to minimize glare and to provide shade.

5. If new parking areas are to be created, these areas should be screened from public view by appropriate fencing or planting strips. Where fencing is to be used, materials should be consistent with wall materials found on historic buildings in the area. Where planting strips are to be used, such strips should be wide enough to allow for the planting of a variety of plant species ranging from ground cover, to medium height shrubs and to shade trees. In most cases, 3.5 feet is preferred as a minimum depth.

6. Entrances for commercial parking areas should be taken from alleys and side-streets to the greatest extent possible. When driveways along major streets are necessary such driveways should be minimal in depth. In most cases 20 feet should be the maximum for a two-way driveway.

7. Building entrances should be kept at a human scale and should be oriented toward the street. The relocation of entrances to alleys or parking lots is generally inappropriate.

8. When commercial uses occupy formerly residential structures, it is preferred that use of the front yard be retained for landscaping and that parking areas be confined to the rear yard so as to preserve a physical record of the property’s original time, place, and use. When conversion of the front yard to another use such as parking or outdoor dining can be found to be appropriate special care should be taken to minimize non-porous surfaces and minimize the construction of bulky physical features such as walls.

Chapter 10 Commercial Rehabilitation: About


The most common feature defining historic commercial buildings is the storefront. While some more monumental historic commercial structures, such as banks, may not have classic storefronts as a ground floor feature, the majority of structures within the commercial areas of Los Angeles’ HPOZs are defined by their storefronts. Although storefront character varies from area to area, there are features common to almost all storefronts. The most typical historic storefront configuration consists of a low base, known as a bulkhead, upon which large panes of glass are set, with a main store entrance located in the center or to one side of the storefront, often recessed from the main facade. Above the largest panes of glass, or the storefront glazing, there is often a band of narrow, horizontal panes known as transoms or clerestory glazing. The store’s signage was historically located on awnings over these windows, was painted on the glass itself, or was located in a sign area just above the clerestory or transom glazing. Often, storefronts will include a second, less prominent door leading to second story offices or apartments.

Preserving the character of historic storefronts is essential to maintaining the character of historic commercial areas. Sometimes storefronts have been radically changed over the years through in fill of windows, the exchange of doors, and often through an accumulation of signage obscuring storefront features. I t is therefore important to carefully analyze the ground floor of an historic commercial structure to ascertain the original con figuration of the storefront area before beginning work.

Historically, as today, signage was a detail that played an important role in defining the character of historic commercial areas. The placement and design of signage is therefore an important consideration in preserving the historic character of a commercial district.


1. Historic commercial entryways should be preserved, both in their form and their individual components.

2. If windows or doors on an historic storefront must be replaced, they should be replaced in kind, matching the materials, dimensions, and glazing of the originals.

3. If an original storefront or its details are missing, replace them with new details in the same design as the originals if the original design is known. If the design is not known, the design of the storefront or storefront details should be compatible with the size of the opening, and the style of the building. There are usually design cues that can be drawn from other nearby historic buildings that may assist with the reconstruction of a storefront.

4. The transparency of first floor storefront and transom windows should be maintained. Painting or mirroring storefront or transom windows or entry door glazing is inappropriate.

5. Filing in historic storefronts, or altering them with smaller openings is inappropriate, regardless of the internal use.

6. Fixed bars or prominent roll-down gates are inappropriate on historic storefronts. Security grilles and their housing, when used, should be on the interior of a structure, or if mounted to the exterior should be completely concealed from view during open hours. Window film that protects the window from vandalism while maintaining transparency is encouraged.

7. Signs should be designed and placed in such a way that is consistent with the size and style of a building and that does not conceal or diminish the architectural features of that building. If a storefront includes a raceway for signs, then any new wall signs should be confined to this area. If signs were historically mounted to a structural canopy, or included on awnings, then new signs should replicate this pattern.

8. Externally illuminated signs are generally preferred when illumination is to be used at all. If internal illumination can be found to be appropriate, reverse-cut channel letters or neon are preferred. Internally illuminated channel letters and cabinet or box style signs are generally inappropriate

9. External signage should not be installed over storefront windows, doors, or transom areas.

10. Internal signage that substantially blocks the transparency of storefront windows is inappropriate.

11. Awnings should be similar in materials, design, and operation to those used historically. Most often awnings would provide breaks where the building provides structural bays. Internally illuminated awnings and vinyl awnings are generally inappropriate.

12. Most historic storefronts provided a bulkhead between the ground and the storefront window. The bulkhead usually consisted of a durable and decorative material such as masonry or tile. Care should be taken when reconstructing a storefront to include a bulkhead when appropriate and to finish the bulkhead in materials that are appropriate to the style of the building and the Period of Significance.

13. If a formerly residential structure is being used for commercial purposes, care should be taken that the outward appearance of the structure remains residential. A recon figuration of the ground- floor of the house to provide an expansive storefront, for example, would be inappropriate.

14. Signs used for commercial uses in formerly residential structures should not obstruct architectural features and should be diminutive in scale and appearance if they are to be located directly on the structure. In many cases, signs that are freestanding monument

signs will be preferred. Signs that break the roofline are not permitted by the City.

Chapter 10 Commercial Rehabilitation: About


Windows and doors strongly de fi ne the character of a structure’s design through their shape, size, construction, façade arrangement, materials, and profile. Important defining features of a window include the sill profile, the height of the rails, the pattern of the panes and muntins, the arrangement of the sashes, the depth of the jamb, and the width and design of the casing and the head. While the materials used and the level of detain may vary, traditional historic storefront windows usually provided expansive windows that attracted pedestrian traffic and allowed for views into and out of a store.

Doors in historic commercial areas vary from glazed storefront doors to opaque, simple secondary entrances. In addition to the door itself, historic commercial entryways were often framed by a surround, which might have included a portico, sidelights, transoms, recessed entryway details, and other features whose preservation is important to its character. In some cases, the color and texture of the glazing are also important.


1. Preserve the materials and design of historic openings and their surrounds, including hardware.

2. The historic pattern of openings on a façade should be maintained.

3. The size and proportions of historic openings on a façade should be maintained.

4. Filling in or altering the size of historic openings, especially on primary facades, is inappropriate.

5. Adding new openings to historic facades, especially on primary facades, is also inappropriate.

6. Repair windows or doors wherever possible instead of replacing them.

7. When replacement of windows or doors is necessary, replacement windows or doors should match the historic windows or doors in size, shape, arrangement of panes, materials, hardware, method of construction, and pro file.

8. Replacement windows or doors on the rear of side facades and the rear facade may vary in materials and method of construction from the historic windows or doors, although the arrangement of panes, size, and shape should be similar.

9. If a window or door is missing entirely, replace it with a new window in the same design as the original if the original design is known. If the design is not known, the design of the new window should be compatible with the size of the opening, and the style of the building. There are usually design cues that can be drawn from other nearby historic buildings that may assist with the replacement of windows and doors.

10. Fixed bars or prominent roll-down gates are inappropriate on historic storefronts. Security grilles and their housing, when used, should be on the interior of a structure, or if mounted to the exterior should be completely concealed from view during open hours. Window film that protects the window from vandalism while maintaining transparency is encouraged.

11. Burglar or safety bars that are not original to an historic structure should not be installed on facades that can be seen by the public.

12. Bars or grillwork that is original to the structure should be retained.

13. Doors and windows on a formerly residential structure that is currently used for commercial purposes should be preserved consistent with the Residential Rehabilitation Design Guidelines in Chapter 7.

Chapter 10 Commercial Rehabilitation: About

10.5 ROOFS

The character of the roof is a major feature for most historic structures. Similar roof forms repeated on a street help create a sense of visual continuity along a street front. Roof pitch, materials, size, orientation, eave depth and con figuration, and roof decoration are all distinct features that contribute to the character of a roof.

The majority of commercial and institutional buildings in historic neighborhoods are built with flat roofs surrounded by a parapet, though in some cases buildings may provide pitched roofs. These roofs were necessary to the form of the historic commercial building, and should be maintained. While the materials used on a flat roof surrounded by a parapet may not be of the greatest consequence, the maintenance and preservation of other roof details such as vents, cornices and decorative architectural features is significant. Commercial structures built in the Spanish Colonial Revival and Mission Revival styles often sported terra-cotta tile roofs that are a distinctive element of these commercial structure. Parapet details were also often used in historic commercial structures to add architectural interest.

Before undertaking any work on a commercial roof, first consider photographing the areas where work will be done. Some of these elements may have to be removed while the work is done, and it can be helpful to have a record of what they looked like before work started when the time comes to put them back in place.


1. Preserve the historic roof form.

2. Preserve the historic eave depth or cornice design.

3. Historic cornice detail should be preserved in place whenever possible.

4. If historic cornice detail must be removed, it should be replaced with details that match the originals in design, dimensions, and texture.

5. Historic specialty roofing materials, such as tile, slate or built-up shingle, should be preserved in place or replaced in kind.

6. Replacement roof materials on visible roofs should convey a scale, texture, and color similar to those used originally when original materials are not available.

7. Dormers should not be added or removed from historic rooflines.

8. Rooftop additions should be located to the rear of the structure and designed so as to minimize their impact on visible roof form.

Chapter 10 Commercial Rehabilitation: About


Architectural details showcase superior craftsmanship and architectural design, add visual interest, and distinguish certain building styles and types. Features such as lintels, columns, and applied decoration were constructed with materials and finishes that are associated with particular styles, and are character-defining features as well.

Determining the architectural style of a commercial building can help you to understand the importance of its architectural details. The architectural styles section of these guidelines, or your HPOZ board, can help you determine what architectural details existed historically on a particular historic structure.

Decorative details should be maintained and repaired in a manner that enhances their inherent qualities and maintains as much as possible of their original character. A regular inspection and maintenance program involving cleaning and painting will help to keep problems to a minimum. Repair of deteriorated architectural detail may involve selective replacement of portions in kind, or it may involve the application of an epoxy consolidant to stabilize the deteriorated portion in place. These options should be carefully considered before architectural detail is replaced, since matching architectural details often requires paying a finish carpenter or metalworker to replicate a particular element, which can be a major expense.


1. Preserve original architectural details.

2. Deteriorated materials or features should be repaired in place, if possible.

3. When it is necessary to replace materials or features due to deterioration, replacement should be in kind, matching materials and design.

4. When original details have been lost and must be replaced, designs should be based on historic photographic evidence. If no such evidence exists, the design of replacement details should be based on a combination of physical evidence (indications in the structure itself) and evidence of similar elements on commercial structures of the same architectural style in the neighborhood.

5. Materials, such as masonry, that were not originally painted should remain unpainted.

6. Original building materials and details should not be covered with stucco or other materials. If stucco is resurfaced, care should be taken that details are not lost.

Chapter 10 Commercial Rehabilitation: About


The characteristics of the primary building materials, including the scale of units in which the materials are used and the texture and finish of the material, contribute to the historic character of a building. For example, the color and finish of historic stucco is an important feature of Spanish Colonial Revival commercial structures.

Before you replace exterior building materials, make sure that replacement is necessary. In many cases, patching in with repair materials is all that is needed. For instance, epoxy or another   filler can sometimes be used to repair small areas of damage. Replacement of deteriorated building materials requires careful attention to the scale, texture, pattern, and detail of the original material. The three- dimensionality of wood moldings and trim, the texture of historic stucco, and the bonding pattern of masonry walls are all important to duplicate when replacement is necessary. Replacing or concealing exterior wall materials with substitute materials is not appropriate. For example, placing synthetic siding or stucco over original materials results in a loss of original fabric, texture, and detail. In addition, such surfaces may conceal moisture or termite damage or other causes of structural deterioration from view.


1. Original building materials should be preserved whenever possible.

2. Repairs through consolidation or “patching in” are preferred to replacement.

3. If replacement is necessary, replacement materials should match the original in material, scale, finish, details, profile, and texture.

4. Replacement materials that will match the original in appearance should be considered when original materials are unavailable or too costly.

5. Building materials that were not originally painted should not be painted.

6. Original building materials should not be covered with vinyl, stucco, or other fi nishes.

7. If resurfacing of a stucco surface is necessary, the surface applied should match the original in texture and finish.

Chapter 10 Commercial Rehabilitation: About


Nothing can alter the appearance of an historic structure more quickly than an ill-planned addition. Additions cannot only radically change the appearance of a structure to passersby, but can also result in the destruction of much of the significant historic material in the original structure. New additions within an historic commercial area are appropriate, as long as they do not destroy significant historic features, or materials, and are compatible with both the neighborhood and the building to which they are attached. Careful planning of additions will allow for the adaptation of historic structures to the demands of the current owner, while preserving their historic character and materials.

In planning a new addition to an historic structure, it is necessary to plan carefully so that you can avoid significantly altering the structure’s historic character. The impact of an addition on the original building can be significantly diminished by keeping the location and volume of the addition subordinate to the main structure. An addition should never overpower the original building through height or size. The form, design, placement of windows and doors, scale, materials, details, colors, and other features of new additions should be carefully planned for compatibility with the original building.

While an addition should be compatible, the design of the addition should also be slightly differentiated from the original structure. For example, it can be differentiated from the original building through a break in roofline, cornice height, wall plane, materials, or a slight variation in window pattern. These differences will allow the addition to be distinguished as a new contribution to the historic district, instead of giving a false sense of the area’s history.


1. At-grade additions should be located in the rear of the structure whenever possible, away from the main architectural façade.

2. Additions should use similar finish materials and fenestration patterns as the original structure. A stucco addition to a brick structure, for example, would be inappropriate.

3. Addition roofing forms and materials should echo those of the original structure.

4. Rooftop additions should be executed so that there is clear deliniation between the original facade and the new facade.

5. Additions should be differentiated from the original structure through their details or massing, communicating clearly that the addition is new construction.

6. Rooftop additions should be executed with sensetivity to adjacent single-story residential uses. Massing should be oriented toward the commercial street and away from adjacent residential uses, and open space should be concentrated in central courtyards and away from adjacent residential uses to the best extent possible.

Chapter 10 Commercial Rehabilitation: About
bottom of page