1. Introduction

Historic buildings bear the traces of different periods because of additions attached to the building in different times. Among them, the contemporary new additions, commonly applied as part of historic preservation treatment, either in the form of exterior additions or interior alterations, expand the outer limits of the original building, or create new spaces in building interiors [1]. A new exterior addition is mostly required for programmatic reasons and is accepted as an appropriate alternative only if "the new program requirements cannot be met within the existing building envelope" or by altering only interior spaces without changing character defining features of the building [1–4]. Interior additions are similarly applied to make compatible use of the property through interior repairs

and alterations [4]. As US Standards for Rehabilitation & Guidelines for Rehabilitating Historic Buildings has proposed and if an exterior addition has to be done, it should be clearly differentiated from the original and should be built without damaging character defining features of the old [4]. This research examines the new exterior additions and interior alterations observed in five case study historic buildings, three khans and two mosques, across historic Ulus district, in Ankara. They provide examples of both adaptation projects and original use, all maintaining significant details of the old building, and at the same time have new additions that attract public attention. Selection parameters are; they should be public buildings, they are to be located in historic fabric of city of Ankara, and their new additions should exemplify either the need for adaptive reuse or continuous use of original function of the old building. Main objectives of the study are first to question the compatibility of the new additions and alterations with international standards and to investigate their contributions to sustainable development of the district. It begins with a literature review on the type of new additions to existing built heritage, followed by international legal framework and guidelines on new additions and continued with case study buildings and their new additions with an evaluation of their compatibility with the standards and their sustainable contributions.

There is a vast amount of literature on new additions to historic buildings [5–14]. Among them, there are various studies examining the issue of evaluating those new additions, possible approaches applied in their designs, and their appropriateness to the historic fabric [5–10]. New additions have also been discussed by scholars within adaptive reuse and rehabilitation framework and with a focus on sustainable benefits of rehabilitation [11–14].

There are also considerable literature related to prehistoric and historic development of historic city center of Ankara; on municipal, construction, agriculture, and commercial activities mainly in historic Ulus district, and related to urban, archeological, natural, and historical protected areas and strata's of the area [15–22]. Among them, Taş's research includes a comprehensive archival research on commercial activities, administrative structure, neighborhood, and public and private life in the seventeenth century Ankara [18]. Various studies similarly focus on the historic districts and architecture of the city including historic buildings belonging to Roman, Seljuk, Ottoman, and Republican periods [23–29]. Though in limited number, some scholars also examined the urban conservation process in Ulus district and alterations and special transformations of historical buildings in due course, as well as their sustainable conservation issues [30–33].

Although, all those existing literature tend to focus on architecture and history of Ulus district, and they rarely address the issues of new additions to historic buildings and their contributions to sustainable development in the area. Hence, this study is significant in terms of providing data on compatible and incompatible new additions to the case study old buildings located in the district and providing evaluations on their contributions to the revitalization of the area.

#### 1.1 New additions to existing built heritage

New exterior additions, as part of rehabilitation treatment, can be inevitable in order to extend the longevity of the historic building falling into disuse because of the problem of abandonment, misuse, or damage. Changes in present day requirements, programmatic needs caused by adaptive reuse, and need for the completion of damaged parts in historic buildings esthetically, functionally, and structurally, as well as user expectations also cause differentiations in the form of exterior additions and/or interior alterations to the built heritage [9, 34]. Al-Jameel and Saffo (p. 3)

New Additions to Existing Built Heritage and Their Contributions to Sustainable… DOI: http://dx.doi.org/10.5772/intechopen.82734

#### Figure 1.

New additions designed according to three different approaches: Standard, contrasting, and identical [3, 7, 39, 40].

also counts the "factors such as natural changes, disasters, social, economic, cultural and political transformations" among the very reasons of constructing new additions with different types and models [35].

There is not a certain formula about the type and form of the addition, such that it can be "traditionalist, contemporary or a simplified version of the historic building", as long as it preserves a balance between the differentiation and compatibility [36]. Though there are some recommendations, there are not certain rules on scale (height and width), form, massing, setback, orientation, alignment, rhythm, spacing, and proportion of a new addition [1, 3, 4, 37]. It can be as small as a vestibule, or as large as an entire building mass, but it is encouraged that it should be smaller than and not overwhelm the original building and should be less visible from the street side [2, 37]. Hence, it is more appropriate to position a new addition at the rear or side elevation of the existing building, and front additions are to be avoided as much as possible [37].

According to "The Secretary of the Interior's Standards for the Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring & Reconstructing Historic Buildings", White (p. 38) categorizes the various recommended and discouraged methodologies toward additions to historic buildings in three groups: standard, contrasting, and identical [7] (Figure 1). Standard approach is explained as "compatible," but "differentiated" from the old, thus ensuring that it "subordinates" to the historic building [7]. Also known as abstraction, in this approach, a new addition should be similar, but slightly different from the original building [6]. As another approach, contrasting style is defined as in "extreme contrast" to the old, thus avoids potential misunderstanding of what is original and what is new [6, 7]. On the other hand, in identical approach, new additions are almost the same with the old, in terms of style, design elements, material, scale, and detail [6, 7]. Semes similarly defines four possible strategies in designing new construction in a historic setting and calls them as the following; "(1) literal replication, (2) invention within the same or a related style, (3) abstract reference, and (4) intentional opposition [38]."

In addition to above mentioned design approaches, there are also some criteria that should bear in mind in designing new additions. Tanaç-Zeren (pp. 31–33) explains the criterion in new additions constituting the esthetic impression as follows [34]:


According to the historic preservation standards, primary exterior new additions include [1, 3, 4, 7, 41] (Figures 2 and 3);


Tanaç-Zeren (pp. 37–38) groups those new additions, which were generated as part of space and program requirements of secondary functions given to the old buildings, as follows [34]:

Figure 2.

Drawings showing different types of appropriate additions according to the City of Houston historic preservation manual, 2015 [7].

#### Figure 3.

Different configurations of appropriate and inappropriate new additions to historic buildings [37].

New Additions to Existing Built Heritage and Their Contributions to Sustainable… DOI: http://dx.doi.org/10.5772/intechopen.82734


There are also front and basement additions observable in historic buildings. But, especially the front additions are mostly avoided or even prohibited in order not to hinder the visibility of the original building from the street side [37].

US Secretary of the Interior's Standards for Rehabilitation recommend that functions and services necessary for the new use are to be located in noncharacter defining interior spaces instead of constructing a new exterior addition [1]. Interior alterations may include "inserting an additional floor; an entirely new mechanical system; or creating an atrium or light well, but such alterations should not radically change, obscure, or destroy character defining spaces, materials, features, or finishes" [42].

### 2. International and legal framework and guidelines on new additions

In principle, world's leading preservation organizations such as United Nations Educational, Scientific and Cultural Organization (UNESCO), the International Council of Monuments and Sites (ICOMOS), and the U.S. National Park Service (NPS) oppose to the attachment of new additions to historic buildings [6, 10]. Nevertheless, they welcome compatible additions if required for the benefit of users and for present day use as long as they do not affect character defining features of the old building [6]. Those primary international charters, guidelines, and standards related to new additions to historic buildings and their related articles/sections are given below:


In addition to those international guidelines, in Turkey, there are also some regulations, which partially mention about the new additions to historic buildings though there is not a regulation solely related to the issue [51–53]. Among them, The High Council Resolution No: 731, dated 19.06. 2007, regulates the restoration interventions, applications, and inspections for the cultural heritage such as mosques, masjids, and tombs supervised and managed by Directorate General of Foundations [51]. According to this Resolution, in adaptive reuse of monumental historical buildings with waqf root, their original functions, if specified in their waqf documents, are to be preserved. Any kind of house reserved for someone who holds a particular job in a mosque or shops/stores cannot be built attached to the historic building itself or in their courtyards. Similarly, late comers' portico cannot be closed even with glass material, and in ablution spaces and in such areas, new material use that will destroy the traditional texture both structurally and visually is not allowed [51]. In addition, The High Council Resolution No: 660, dated 05.11. 1999, groups the immovable cultural heritage and regulates the conditions of their maintenance and repairs [52]. In this Resolution, it is noted that, if a new function is to be given to an old building, opinion of the Conservation Board is to be taken regarding the characteristics of new additions and their integration with the old, and those new additions can be applied only after its approval by the mentioned Conservation Board [52]. Furthermore, in The High Council Resolution No: 720, dated 04.10.2006, on Conservation and Usage Conditions in Urban Protected Areas, it is stated that it is not possible to build new buildings whose locations and height might adversely affect the protected urban silhouette of the street or zoning island that they are located [53]. Those existing regulations in Turkey show that they lack a detailed explanation about the approaches, types, and recommendations on application procedures of new additions to old buildings.

## 3. New additions to historic buildings and their contributions to sustainable development: cases from Ankara, Turkey

The case studies discussed in this part of the chapter are all historic public buildings, easily accessible located in historic Ulus district, in Ankara. The cases clearly exhibit both compatible and incompatible exterior and interior additions according to the international guidelines. Most of the examples selected were built in the sixteenth century, and the architectural landmark of the district and the additions were attached in last 80 years. In all of the cases, the exterior and/ or interior additions, either in the form of small interventions or major additions, were attached to the existing building during the extensive restoration works. The case studies involve front, rear, side, basement, storefront, and rooftop exterior additions and some interior alterations. Among the case studies, the mosques are still used in their original function, and the khans exemplify adaptive reuse rehabilitation treatment; two are converted to a museum and one is started to be used as a boutique hotel. New exterior additions of case studies employ both standard and contrasting approaches explained in part 1.1. of this chapter.
