Video
Advanced Training on Historic Preservation Certification Applications – Webinar #4
Transcript
(Brian Goeken) Hello, my name is Brian Goeken and I am the Chief of the National Park Services Technical Preservation Services Office. Thank you for joining us for the 4th of this 5 webinar training series on the Historic Preservation Certification Application and the application submission requirements. In this webinar, we are continuing to focus on Part 2 applications with a comprehensive overview of the documentation requirements, as well as including for special circumstances such as additions, new construction, and demolition. Presenting today are John Sandor and Liz Petrella from the TPS office.
(John Sandor) This is John Sandor with Technical Preservation Services. I'm here today to share with you the guidance that we provided back in September to program users on drawings that accompany certification applications.
At least some drawings are needed for every application, even if it's just to locate the photographs. What drawings are needed will depend on the size and complexity of the project. Worth reminding ourselves what the drawings can provide. In addition to locating the photographs, they do give us a visual framework for orienting the narrative. They allow for an efficient visual comparison of existing features to proposed alterations and Replacements.
And they reinforce and clarify the narrative, but they do not replace it. Things that drawings should include to maximize their usefulness. Never hurts to have a North arrow, and it's absolutely critical if you're going to use the cardinal directions in your narrative description. An index is not required if they're only a few sheets, but for anything more it's really essential. Especially with these electronic files and trying to find your way through to the page you need.
An index makes it just more efficient for us to find our way through the set. If you're pulling notes into keys, then those need to be easily found, if not repeated on each page. When changes are very few, they may be adequately represented on a single set of drawings, but typically we're going to have separate sets of existing and proposed conditions. Beyond the basic plans, what drawings are needed will be specific to the building and the work being proposed. More complex projects can be expected to need more drawings.
For smaller projects, relatively simple, even sketch drawings may be fine. The drawing used in the photo key may even be adequate for a small building with little or no change to the plan. Though the reduction necessary to get this drawing sheet on the slide makes everything seem rather small, it exemplifies a pretty typical drawing useful for review. There can be a tradeoff between splitting up individual levels into more than one sheet, where things can be a bit larger and easier to read, and having each level contained on a single sheet, but that's a decision of the architect and not a choice for us to dictate. This example of a drawing for a larger project is legible with a little zooming in, and the full plan is contained on one sheet.
The sheet is numbered to facilitate referencing it in the narrative. There's a North arrow, and the key, notes, and legend are on the sheet itself, which makes understanding the notes much faster. While a small-scale drawing may be enough to convey the relationship of a specific feature like a storefront for the overall elevation, the size, profiles, and relationships of individual parts cannot be discerned and the built result may not be as expected. Which was exactly the case with a little drawing on the left compared to the if you compare it to what was built immediately adjacent. If the whole thing looks like it was stamped out with a cookie cutter from a single sheet of material rather than assembled from parts, we cannot tell what is going on -- what it's going to look like in 3 dimensions.
It does not tell us how elements intersect or what their profiles are, which presumably leaves such decisions up to the person building it, who may have no clue as to the desired appearance. Details aside, what was built is not consistent with what was drawn. Here on this drawing the details and dimensions that we need to see are at a scale that is legible without having to zoom in and out for everything. In this example of an entry, we have the feature placed in the context of the overall elevation in the drawing on the far right. It is then enlarged enough to have its components dimensioned and represent where the joints are.
Because it's not all in one plane, an enlarged section, and a plan at the top, cropped a little to make it onto the sheet, make it easy to understand the three-dimensional configuration of the new feature. Sections are particularly useful if ceiling heights are being altered, floor cuts are proposed, or rooftop additions are proposed. Hopefully, a scene like this is now a thing of the past. Thanks to our electronic application process. We can be frustrated in other ways now.
However, to the question of can you have too many drawings, the answer is a resounding yes. If there's not a place in the narrative where you would key the drawing. You probably don't need it. Generally, not necessary are code review or life safety drawings. The exception might be to illustrate travel distance, that is justifying moving a door or shortening a corridor.
Structural plans also are not typical for most -- typically necessary for most projects. If framing is being rebuilt, our concern is with the finishes that need to be removed and replaced to facilitate the new framing, not the framing itself. But if structure is exposed or added over finishes, as is sometimes the case for seismic upgrades, then structural drawings would be appropriate to include and should be. Furnishings are not governed by our review and fixtures are rarely our concern. If existing light fixtures are historically significant or are an integral part of an architectural feature such as a grid ceiling, they need to be documented.
And if a large light fixture is being added to a particularly significant space, or architectural lighting is being added to the exterior, those specific details should be included. But we do not need to see every fixture for the average space or location. Any systems plans that are just schematic do not usually provide useful information about the visual effect of what is being added, since sizes and placement of lines are not typically really represented. And we don't need books of construction specifications. At most maybe a page for something like a mortar formula.
For the most part, we just need the applicant to be using their best judgement in deciding what is necessary to send. Mechanical, plumbing, and electrical plants are usually just schematic and don't contain information that's pertinent to our review. However, the placement and size of these features, if not run within the structure, can impact the character of a building. The impact of these systems and what we will see of them belongs in the narrative. In some cases, though, even a schematic plan for plumbing or mechanical can alert us to a potential problem.
But if there is a problem, we should not be discovering it through the plan. It's the applicant's job at the point the application is assembled to identify how systems will be handled and their impact on all but the most secondary spaces. A plan like this one illustrated may be helpful in substantiating why there's a need to do something with the corridor ceiling, given that a four-inch waistline is drawn running down the center. But the plan is just backup information for a problem that needs to be addressed in the narrative and possibly in a section and a ceiling plan. On the other hand systems drawings that they represent the sizes and locations of pipes and ducts as seen in this drawing are useful when systems are exposed.
In some cases, representing them in sections as well can be helpful to convey their real visual effect. Reflected ceiling plans can be useful, particularly in larger projects where they can be where there can be a variety of ceiling treatments. If not illustrated in section drawings, notation of ceiling heights, especially if they are buried from space to space, should be included on the drawings. They also are a good way to reinforce the text description of the specific location of different ceiling materials. Only a site plan for a small site like this one on the left, where the area of paving and turf is not being changed and there are no landscape features being added or subtracted, is not really needed.
A site plan, however, was essential for the warehouse site on the right where a lot of new planting was being proposed for what was a relatively bare open site. Now I'd like to cover some guidance on documentation of windows. Inadequate or missing window documentation is often the cause of delays in project review. We cannot determine the acceptability of a proposed treatment without understanding what's there now, its condition and significance. This documentation will typically consist of both photographs and drawings.
Our guidance describes factors that can be considered in conjunction with deterioration and justifying replacement. These include operation, presence of hazardous materials, code requirements, and energy performance. And if you're citing any of these factors in making the case for replacement, how they might apply needs to be fully explained in the application. Increasingly the historic windows for a project are gone, but that does not eliminate the need to describe what, if anything, is left in the openings. Documentation of the windows or even of the opening starts with photographs.
And you may be able to take most photos from the inside, but they do need to depict the exterior conditions. What you want to show is the deterioration that makes repair unreasonable, if indeed the windows are to be replaced. They need to be close up and specific. Gouged and missing fabric should be represented, as should severely weathering or decay, loss of section bowed, or structural failure. The photo should make that clear regardless of the type of window being documented.
The types of windows and what survives or is missing should be readily discernible from regular elevation drawings. We do not usually need a window-by-window survey documenting every detail of every window specifically, but we do need some general quantification of conditions that you've illustrated generously with the photographs. Conditions typically vary from story to story and from one elevation to another. Marked up elevation drawings can be useful to illustrate particular patterns of deterioration and just what survives, especially when many of the openings are boarded up. While it is obvious that we need documentation of historic windows that are to be replaced, there's often surviving historic material.
Even when a replacement window has already been installed, it may just be covered up. That material can inform the selection of a new replacement window and may affect how you want to install that replacement. Presentation should include photos both the inside and the outside of the window. Without photos from the inside this window on the left, we wouldn't have known whether it had arched headed jamb or a simply a rectangular sash with arched glass in it. Regardless of whether the full historic window survives or just a part of it, we need to know what is intended to be kept in place and what will be replaced.
Are you proposing to install a new window within the historic jambs? If so, why? Could it be that there's distinctive casing that might affect that decision? Or are you going back to the rough opening? Does the window have casing interior trim that will be removed and reinstalled or will it just be replaced with new?
And is that casing even replaceable if it's varnished old growth wood, it might not be. If the casing is to be replaced, we need enough documentation of it before it is removed to be able to determine if the replacement material being installed actually matches the historic. Even if nothing of the original window survives, the nature of the rough opening can provide physical evidence when other sources are lacking. So, the opening needs to be photographed. It can contribute to determining a compatible type, material, and configuration for the replacement window.
In projects where the replacement of windows is an appropriate treatment, we must be able to determine if the proposed replacement windows are an adequate match for the historic ones and thus meet the standards. In order to do that evaluation, we're going to need minimally drawing showing both the horizontal and vertical sections of existing historic windows, including muntins, mullions, transoms, and any trim components. A good photo of the overall window, and perhaps one a bit closer for some details can confirm if the existing condition drawings accurately represent the particular window, or just some random assembly downloaded from the internet. The proposed new window is pretty clearly represented here in this drawing, though a little shy on dimensions. And the historic window lacks dimensions altogether.
But because both old and new are drawn to the same scale and positioned adjacent in the drawing, it's really pretty easy to compare them even without dimensions. Unfortunately, a close look at the photo here indicates that the drawing provided to the existing window really doesn't represent all the components of that window or their actual proportions. If the person who creates the drawings is not the applicant, then perhaps someone should be checking that the drawing really represents what is there and provide us with photos at an appropriate size to confirm that accuracy as well. A sheet on the left from a manufacturer's product literature is almost never adequate documentation alone for a replacement window. It has most of the dimensions we need but does not place the unit in the context of the wall assembly.
For the drawing on the right, there are dimensions, but not the ones we need. They show depth, but not what we see. The drawing also do not show how the individual units are joined, though the overall dimensions in the elevation do give us some sense of the size of the pieces relative to the scale of the openings. They are just pieces pulled from a manufacturer's catalog and, like the drawings on the left, provide no information of where and how the window fits in the wall assembly. The drawings shown here provide the dimensions that will affect what we see and include a mullion detail.
Not only how it matches the historic one but provides assurance of consistency between the mullion and the perimeter. Each material used for Windows has its limitations and possibilities, especially when working from a manufactured line. As you can see from these five sections of clad wood, double hung units no two are exactly alike. And none perfectly match the typical historic section of a wood window. It wouldn't be much better if these were all wood instead of clad.
We realized that unless the replacement is a shop made individual unit, it will not be a perfect match, and thus we are trying to fairly judge what details are critical to reproducing the overall effect in a reasonable manner. As important as section drawings are, elevation drawings, when done to a scale that can accurately include all of the offsets and proportions of a window, can be useful to quickly reveal problems that can be overlooked in section drawings, especially those that are incomplete, and they can be helpful to judge what matters visually. Similarly, photographs of a manufacturer's sample can be useful in determining the overall importance of all the inevitable variations in profiles and dimensions. As useful as an installed sample window may be, lead times and costs make them an unreasonable requirement in many, if not most situations. But if you're trying to convince us that the variations in section dimensions and profiles of your chosen window will not have a significant visual consequence, the next best alternative to a mockup is either a manufacturer sample or, better yet, an existing installation of the same window photographed from a comparable building.
Beyond the dimensions and profiles of rails, styles, sills, and trim, many windows have features that add complexity. The presence of muntins, ogee lugs, width, and design of mullions; design of a transom bar and the plane of the transom sash are all details that are important to the character of a window of which they are a part, and they need to be documented with good photos. They also require detailed and dimension drawings, both of the existing and the proposed replacement. For muntins, we're really looking to find simulated divided lites, not just a grid applied to one side or between the glass. For proposed replacement windows.
When the window is steel, the drawings must again show the elevation and horizontal and vertical section of the windows and the dimensions of the components. Operable vents prevent a challenge when reproducing a traditional steel window in aluminum and using insulated glass and inevitably involves some compromise. Thus, the sections not only of the vent itself, but the muntins needed to support it are important to include in these drawings. With steel windows in particular, there's no better way to evaluate the effect of a replacement window than through a photograph of the equivalent window in a similar installation. For any given manufacturer, there are not so many variables that an equivalent installed unit cannot be found.
Finally, just to touch briefly on glass, the reason that we have windows. We realize that most windows that are being proposed are going to be an insulated unit and are going to want to have Low-E glass. There really a limited number of options for this low E glazing. There are only a small differences from 1 manufacturer to the other and only a very small number of manufacturers that are making these Low-E coatings. We have in our office existing samples of what we consider acceptable, that are adequately clear, as well as those that are beyond the level of normal approval.
So, unless specifically requested, we do not need to have glass samples. All we really need to know is the visible light transmittance, which is the a number that helps us judge which level of visible light can pass through the window and the coating manufacturer. And then we can look and see the sample that we -- from the sample we already have confirmed that it's acceptable or that it is not. Thank you.
(Liz Petrella) I'm Liz Petrella, and I'm a reviewer at TPS. I'll be reviewing documentation requirements for special considerations, specifically rooftop additions, additions, new construction, and demolition.
The guidance in this presentation will help you understand what is required for a review, as well as why this information is required. Rooftop issues can encompass several things, from rooftop additions to green roofs, solar panels, decks and railings, or HVAC equipment. The baseline documentation will be the same for all rooftop features, from railings to full additions. You should review the applicable guidance on the subject first to understand how SHPO and NPS will be evaluating the proposal so that you can ensure you are addressing all necessary issues. Preservation Brief 14 on New Exterior Additions and the Rooftop Additions White Paper from our Planning Successful Rehabilitations page are both great resources to start with and can be found on our website.
If the information submitted with your application is not complete, we will not be able to fully review and evaluate the proposal and it may go on hold or result in a lengthy review time and conditions. The following is general guidance and stems from the rehabilitation standards and guidelines. Each proposed rooftop addition or feature will be evaluated for its specific visibility and impact on the building and district. Rooftop additions are generally not appropriate for buildings less than four stories in height. That said, depending on surrounding density, existing rooftop features and size and set back, a rooftop addition may be acceptable.
The smaller the building, the more impact a visible addition will have. Visibility is evaluated from the public right of way. We will consider existing rooftop features and how they may screen a new feature. Visibility of a new feature from a couple of limited locations will be considered differently than broad visibility from primary viewpoints near the building. A rooftop addition should generally be set back from all visible planes of the building.
The distance will be dictated by visibility. Historic rooftop appurtenances may affect how visible a compatible rooftop feature may be. A rooftop addition should be differentiated from the historic building while compatible with the massing, size, scale, and architectural features. We will review how a new rooftop addition impacts the character of the historic building, the appearance of the roof, and roof profile. An addition generally should not be more than one story high, and this is because a rooftop addition should be inconspicuous from the public right of way.
It is your task to provide SHPO and NPS with the information to show how the project's proposed rooftop addition or feature complies with this general guidance. So, what should you submit? You should document the information on the next few slides in your narrative and application materials, starting with what is the historic character of the building and how does the roof and roof line contribute to that? What are the existing conditions of the roof, roofing, and any rooftop features, both historic and modern, and how does the proposed addition relate to these features? Photographs should be submitted that illustrate the visibility of the roof and existing roof features from the ground.
Is it visible at all? Are there visible rooftop features such as penthouses, skylights, or chimneys? Photographs from the roof itself should be provided that show the roof shape and slope material and if there are any parapets or other features that would affect or help screen the visibility of the new features. What is the programmatic need for this new feature? Can it fit inside the building?
Is the addition or new feature for HVAC, stair pop up, or elevator override? These features are often necessary and will be reviewed in that lens. Or is there a rooftop addition for more usable square feet or another amenity? Not all rooftop additions and features are the same, and they will be reviewed in the context of specific buildings and the effect on its character. There are many types of documentation that can be helpful in evaluating a rooftop addition or feature for compliance with the standards.
Generally, each of these items should be submitted with any proposal for a rooftop addition, including photographs of the exterior and roof area, roof plan, elevations or sight line studies, renderings, and mockups. We can only evaluate the information that we are provided. The higher the quality and the more complete the documentation is, the easier it will be for us to evaluate and less likely the project will be put on hold. Renderings and sketches can be a very helpful tool to help reviewers understand a proposed addition, but it is important that they include views from the public right of way. We need to understand how a person will perceive the new feature from the ground, not the sky.
Mockups can illustrate how visible a new addition or rooftop feature will be. Combined with roof plans, elevations, and renderings, mockups should convey accurate placement and dimensions of rooftop features. All mockups must be accurate to the height and dimensions of the proposed feature. Physical mockups are often best and there are many ways to construct these. They can be aided by computer generated information, especially when it's not possible to construct a physical mockup.
You must mockup all visible features, including railings. Mockup should be constructed in highly visible materials and they must be photographed from many vantage points in the public right of way. It's always better to provide more views than you think necessary than to have not enough and have your project placed on hold. We also want to remind everyone that mockups must include any additional height needed for platforms or raised roof levels to accurately depict the rooftop addition. Here is our building from the rendering.
A physical mockup of the rooftop addition was constructed and photographed. There's a misconception that we only want views from across the street. A rooftop addition may not be highly visible from immediately across from the building, but that is not the only legitimate location to consider. Photographs will always be required of both the immediate surrounding area and from more distant locations within a few blocks and within the public right-of-way. As shown in this image, the mockup is not visible from this close angle.
One block down the street it becomes visible and while there's a tall parapet, it is only at the front of the building so the addition is visible from the side. Views from down the street give a better understanding of how visible this addition will be from within the immediate area. This is a midrise building in an urban downtown where large rooftop HVAC equipment was proposed. We acknowledge that there are limitations in placing rooftop HVAC equipment, including limited roof space and structural conditions. The initial amendment submission included a roof plan, elevations, sight line studies and computer-generated visibility studies.
Roof plans are useful in understanding the footprint of the existing and new features and how far they may be set back from the edge of the building. They do not show the whole picture though and are not enough to fully review the visibility of a new rooftop feature. They should be combined with Elevations, sections, and mockup visibility studies. Sightline studies were provided indicating that a person standing directly across the street and looking up should not be able to see the new equipment. And I'll note that in most cases this is expected that you would not see a rooftop addition from directly across the street, especially in a building this tall with any kind of setback.
What is helpful in these drawings is that not only is the new equipment shown, but also the additional platforms that that equipment will be mounted upon. It also illustrates the existing rooftop appurtenances that can be important in the evaluation process. A new rooftop addition does not necessarily have to be invisible, however, it does have to fit into the character of the building. A site map indicating the location of all views is very important. The number of views should be dictated by the height of the building and the surrounding buildings, as well as the density of the area.
Views should be provided from across the street and then one and two blocks away, depending on the topography. Views should only be provided from the public right of way. In tight urban areas, some views may not be needed at all given the proximity and height of neighboring buildings. The view on the left is from an initial visibility study. SHPO and NPS reviewed the submitted computer generated information and felt that this information was not accurate enough to depict the true visibility of the proposed features.
The base image used was a Google Street View image that has a skewed perspective view and the computer mockup was not based on a dimensional building model or accurate physical evidence. A physical mockup was then constructed and photographed as seen on the right. As you can see, the physical mockup, which has been outlined for clarity, is a more accurate depiction of the proposed rooftop equipment. While in this case visible equipment would be considered acceptable. Accurate information must be submitted so that all parties understand the expected visibility of the new feature.
This photograph depicts the view of another piece of equipment on the roof. This is a view from about two blocks away, taken from within the public right of way. It is important that the initial views are provided of what a person standing on the street would view with their own eyes. Once we've zoomed in a little, you can see the mockup of one piece of equipment at the rear of the building. This image is very useful in determining how visible, and therefore how compatible this new feature will be.
Zoomed in once more, you can really see the presence of the mockup and it's easy to confirm that yes, there is a mockup. Sometimes the farther distance photos make it hard to confirm an appropriate mockup was actually constructed. Zoomed in photos or telephoto photographs are helpful for reviewers to understand the presence and placement of the mockup, but they should not be submitted alone. The original image depicting the real-life view is important and it's useful to submit them together. This is another tactic we sometimes see when presenting rooftop additions.
Well, this treatment of whiting out all surrounding buildings is helpful in visualizing the proposed rooftop addition. You are doing yourself a disservice regarding the prominence of the new feature. Images like these may be helpful for the architect in showing off the new feature, but it is not an accurate depiction of how the addition will look in real life. Rooftop HVAC should always be on your radar and documented in an application, especially if you are adding other rooftop features that will limit its placement or impact its visibility. Not all rooftop additions and features should have the same treatment.
It should always be based on the facts and circumstances of each building and its surroundings. SHPO and NPS need to know the details of any cladding such as brick, metal panel, fiber cement product, or finish of rooftop HVAC equipment. Decisions on what cladding is most appropriate will consider the building's materials and those of any adjacent buildings that would be within the viewshed. Computerized mockups or renderings with cladding options can be very helpful in determining which material will be compatible for the new rooftop feature. Comparable views with color options from various viewpoints can be submitted for reviews, such as these two views with a dark and a light rooftop cladding proposed.
In order for the SHPO and NPS staff to evaluate new additions, there are certain documentation requirements. Generally, additions must be subordinate to and compatible with the existing historic building to which they are being attached. The following may help you remember all the questions you may want to ask yourself in order to provide the materials needed to have a quick and successful review and approval process of your next addition. Before getting into any specifics of an addition proposal, a clear description of the scope of work should be provided to include the rationale behind the approach and the design of the new addition. A clearly defined scope of work and rationale often yield short turnaround times for your application.
Additionally, it is important to explain why the same programming cannot be accomplished within the existing building envelope. Is this a small egress stair tower addition or a substantial increase in square footage for additional residential units? Once the need for an addition is established, the first question related to any new construction or new addition to a historic building is what is the existing context? As you all know, providing an understanding of the existing site and environment through text and graphic documentation is necessary to give SHPO and NPS the context for any new construction. Here we not only have views of the subject property but also views of the buildings immediately surrounding it.
Here we want to take note of and document the massing, scale, fenestration patterns, materiality, setbacks, etcetera, of the existing context. As you may have found in your experience, understanding the historic context is important in informing the location, size, massing, and materiality of additions. Resources we typically rely on are historic photographs, Sanborn maps, and of course, National Register nominations. Historic documentation can be beneficial in understanding previous buildings that existed on site, which may provide a useful strategy in designing an addition as urban infill. In these situations, it may be appropriate for the new addition to visually read as a separate building rather than as an addition to the historic building, which often lends itself to more flexibility in design and materials.
After studying the property, the existing context and the historic context determine the most appropriate and compatible location for a new addition. Proposed additions should be clearly illustrated through the use of site plans to show how and why this location is the most compatible location for an addition on the subject, historic property and in the surrounding area. The key to a successful design is that it is subordinate to the historic building in massing and is compatible in scale materials and set back. In order to illustrate the proposed additions, compatibility to the existing historic building, dimensioned floor plans and elevation drawings as well as section drawings and often renderings must be provided. Similar to rooftop additions, visibility can have significant impact depending on the site and setting.
In situations where the new addition will be highly visible, sight line studies or renderings of the proposed addition should be taken from multiple vantage points around the building to fully convey the visual impact of the addition to the historic building. Often plans and elevations are enough to understand the proposed new addition and its compatibility with the existing structure. However, sometimes unique section details or three-dimensional graphics are helpful to better understand what is proposed. While not required, these types of graphics can help expedite review by illustrating complicated building forms and spatial relationships that may not come across as easily in black and white line drawings. New construction may be feasible within the boundaries of historic properties if site conditions allow and if the design, density, and placement of the new construction respect the overall character of the site.
Much of the information required for new additions is also required for proposals for new construction. All new construction should be fully described in writing in the Part 2 application, but the following graphic information is also needed to assess whether the proposed new building will meet the standards. This includes setting, historic context, and design. Protecting the historic setting and context of a property, including the degree of open space, and building density, must always be considered when planning new construction on a historic site. Just as we discussed, for new additions, we first need an understanding of the existing site and environment.
In order to assess the historic site and context, the arrangement of buildings on the site must be identified and whether there is a distinctive urban, suburban, or rural character. If the historic building is in a historic district, photos of the surrounding district that show typical building heights and setbacks should be submitted. This applies to residential neighborhoods as well as commercial ones. As mass and scale of the existing buildings is important information in assessing new construction. One of the most common property types for which we see new construction proposals are schools or institutional campuses.
Photo documentation of the entire site is needed, as well as the surrounding neighborhood to assess compatibility of the proposed construction. Site plans showing the location of the historic buildings and the proposed new construction must be submitted. As illustrated in these examples, site plans can provide varying levels of information. Schematic site plans may be acceptable for preliminary reviews, but formal applications should include a detailed site plan with specific building, landscape, and dimension details as appropriate. Landscape plans are helpful in understanding both existing and proposed features, particularly if they show any grade changes in the landscape that limit building location options or impact visibility.
Similar to new additions, historic context is important in informing the location, size, massing, and materiality of new buildings on site. If there was previously a building on that part of the property, it should be documented via Sanborn maps or historic photographs. The three images on the screen illustrate an example where historic documentation provided justification for multiple new construction buildings within one historic site. This industrial manufacturing complex was densely developed historically, as seen on the Sanborn map. Like many industrial sites, the aerial view in the center shows the significant number of structures lost over time with large areas of open land on the site at the start of the project.
The image on the right shows the conceptual proposed -- conceptual proposal of six new buildings to reestablish a compatible density the historic complex once had. The new buildings should not attempt to replicate the previous buildings but should be compatible in design while preserving the historic relationship between existing buildings. A development proposal such as this may not be successful without the documentation of the property's historic context. One of the most important aspects of historic context in assessing new construction is the historic property boundary. Modern parcel boundaries often differ from the historic property boundary, which should be clearly identified and documented as part of the new construction proposal.
One of the first questions NPS will ask is, is the new construction on the historic property? If yes, then we must review it and the proposal will need to meet the Secretary of the Interior Standards. If the new development is located outside of the historic property boundary, then NPS has no purview and it does not need to be included in the application. This is example shows a new apartment building constructed between two unrelated historic properties. As this new construction was on a separate unrelated parcel and did not connect to either historic building, it did not fall under NPS review.
Drawings should include dimensions, especially the building height and information regarding materials for cladding and roofs. Site plans and elevation drawings are typically sufficient. Construction drawings of the new construction are typically not needed or wanted. The architectural drawings provided should be limited to what is critical in conveying the design, massing, and materials to be reviewed in the context of the historic property. Drawings and renderings must show the new building in context with the historic building.
We understand that not every project team can produce highly detailed renderings to accompany the typical architectural drawings. As shown in the four examples here, 3D renderings can be done in many different styles with varying levels of detail. A combination of renderings should be provided to NPS to fully communicate the proposed construction, which in turn will help expedite review. Site elevations or site section drawings are another important tool in illustrating a new construction proposal. These provide an understanding of the new building in context of the historic building landscape and grade changes, providing a clear sense of the height and spatial relationship between buildings.
These drawings should include height references on all building components. The image on top shows a typical site elevation with the new building in context of the historic, with height dimensions noted. The image at the bottom helps convey the complexity of various buildings and landscape features on that particular site, providing a simple site elevation drawing as supplement to the typical architectural drawings can help avoid delay in the review process. Whether it's a rooftop addition, a building addition, or new construction, it is important that the materials proposed are compatible with the historic property. Therefore, material specifications documenting the product's appearance, color, texture, finish, and compatibility with the historic materials must be provided.
I'm sure none of us here want to advocate for the demolition of buildings, but unfortunately, it's a reality that we're sometimes faced with. Given the finality of such a treatment, demolition proposals must be carefully evaluated in context of the standards and the overall rehabilitation project. In an effort to provide an understanding of how NPS approaches review, the 4th and final section of this presentation will take a look at the parameters for demolition approval. In multiple building projects where the structures are functionally related historically, program regulation state demolition of a component may be approved in limited circumstances with three specific points of opportunity. It's important to note this policy is only applicable to multiple building complexes and is reviewed in context of cumulative effect.
We'll take a look at the documentation requirements to meet the threshold for each of the three regulation circumstances. The first circumstance is the easiest to document and justify. When a building was constructed outside the period of significance of the property or district, this is usually straightforward to identify and you are all well familiar with this type of situation. The base level of documentation required would be a written description of the building with photographs of the existing condition, justification as to the non-historic and non-contributing status in context of the National Register nomination, and any historic documentation that confirms the construction. We often see this in smaller scale additions or freestanding buildings within large complexes, but as you can see in these images of a 1941 aviation plant, even a large building component could have a quick path to demolition approval if appropriately documented to be outside the period of significance.
Circumstance two allows for demolition in two situations. One, the building's physical condition is so deteriorated it no longer has integrity. In addition to the baseline documentation requirements, a structural engineer's report may be required to demonstrate this. And two, when a component has been altered to the point where little to nothing remains of the original building fabric and therefore has lost integrity, additional documentation of these alterations, such as what changed and when, would need to be provided. A simple question to consider for this would be is the building still contributing in its current condition?
The third and final circumstance for demolition is when the building component is secondary or generally lacks significance and retention is not technically or economically feasible. The most common example of this situation would be a large-scale mill or industrial site where the complex grew and evolved over time. In the site plan on the far right, we see a mill complex with over 30 building components. Documentation was provided with the Part 1 to identify each of the components, most of which date within the period of significance. However, several of these were historically and architecturally insignificant, some even being roof structures added between earlier buildings to create additional interior space.
By providing additional information on the context of these components within the overall property and historic significance, strategic demolition of these secondary components was able to meet the regulation. These areas are shown in red. This was done in order to reopen areas of the property to allow rehabilitation for residential use with light and ventilation requirements. The two images on the left show the pre-rehab condition and completed demolition. This strategy is an example of how the demolition policy provides flexibility within multiple building complexes when reviewed in the context of cumulative effect.
As I mentioned, Circumstance 3 of the demolition regulation states the component generally lacks significance and retention is not technically or economically feasible. The second half of that is important in meeting the regulatory requirement. Documentation requirements on the left of the screen would lead one to proving up the general lack of significance. Then, with justification as to why retention of the building is not technically or economically feasible, NPS could determine demolition to meet the standards in context of the overall project. We've looked at examples of demolition in context of the regulation language that were progressively more challenging and would require increasing levels of documentation.
As this is advanced training, we want to provide an example that represents an extreme instance of demolition, one that does not fit neatly into the regulation language. As part of this three-building automotive complex, demolition was proposed for the building shown here in red. Constructed within the period of significance the building is contributing and is significant to the historic property. Documentation was provided that showed the building had inherent structural deficiencies from the day it was built, with a roof and partial floor collapse during construction. The applicant was required to provide detailed analysis and documentation of current structural deterioration.
This included extensive photography, exploration of alternative treatment options, and ongoing discussions with SHPO, TPS, and National Register staff. The NPS administrative guidance outlines expectations for a structural engineer's report. The report must be objective and explore options for structurally stabilizing, reinforcing, or otherwise preserving the building's existing physical and historic characteristics. The report should not solely seek justification for demolition. These images illustrate the various documentation and graphics created by the architects, structural engineers, and project team to illustrate the structural deficiencies of the automotive complex.
Again, this is an extreme example of where demolition was ultimately justified for technical and economic feasibility issues, but this situation is not typical and should be communicated early in the process with substantial review anticipated. Another challenge an applicant may face in rehabilitating large industrial sites is the need for fire apparatus access roads due to life safety and code compliance. In the aerial photo and site plan shown here, you can see the significant density of this manufacturing facility that is bound by railroad lines on multiple sides. In order to meet fire code, demolition of select buildings was proposed to create access roads shown in red. In addition to baseline documentation for demolition, as we've discussed, this situation requires additional documentation, including a written description of the compliance issue with code citations, a description of the alternative treatment options that were considered, and documentation from the local code official attesting to the limitation of options.
These projects are reviewed on a case-by-case basis. As you all know, the National Park Service has tons of great guidance on all aspects of the rehabilitation process. Please use it. And if you can't find the answers you're looking for, please feel free to ask both SHPO and your NPS reviewer. Whether you are working with the proposal for a rooftop addition, building addition, new construction, or demolition, we strongly encourage you to request a preliminary review via your SHPO.
These are four of the biggest scope of work items that can create significant delays in project review, and we can often help avoid issues by having the opportunity to provide feedback early in the planning and design process. (Brian Goeken) Thank you for listening to the 4th of this 5 webinar training series on the HPCA application. We hope you found this information helpful. The other webinars that are part of this training series, as well as the HPCA application form, application instructions, contact information, and how to subscribe for news and updates from our office are all available on the main page of our website.
Description
This webinar continues the discussion of the Historic Preservation Certification Application Part 2 – Description of Rehabilitation with a comprehensive overview of submission documentation requirements, including for architectural drawings, documentation requirements for replacing windows and for special circumstances such as additions, new construction, and demolition.
Duration
53 minutes, 26 seconds
Date Created
05/20/2025
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