Definitions

Georg Giebeler

0

"Kolumba", art museum of the archb ishopr ic of Cologne, Cologne (D), 2007, Peter Zumthor Frauenkirche, Dresden (D), 1743/2005, George Bähr The plann ing work requ ired for various types of refu rb ishment work

There is no universal ly app licable term that covers all bu ilding measures on existing build­ings and is also understood as such. lnstead, we have a number of terms that ex1st alongside the word refurbishment and mean someth ing similar, indeed , even the same thing: conver­sion, maintenance, modernisation , total refur­bishment, deconstruction , works in the building stock, restoration, renovation . There are several reasons for this vag ueness. On the one hand, the degree of change, compared to the extent of the build ing fabr ic to be retained , varies greatly - from minor repairs tototal refurbishment of the entire building . On the other hand, the in­tervention in the existing building fabric is carried out for totally different reasons- aesthetic, tech­nica! or functional . In add1tion, a "traditionally" imprecise choice of words makes it impossible to assign the words exactly to the measures involved . Nevertheless, th is chapter wil I attempt to define the various terms and distinguish them trom each other. The purpose of this 1s not to achieve irrevocable definitions, but rather a classification that wil I provide architects with a planning aid. Different types of intervention in the building stock cal I for both di fferent planning methods and different building measures. lf the architect is in the position to be ab le to assign a certain term to his task, this can help to clarify the plan­ning and construction processes. The terms wil I therefore be exp lained and defined below. In addi tion , practical advice for the realisation of the planning assignment wil I be given. The classification will be carried out according to two aspects: firstly , the extent of the interven­tion in the existing building fabric; secondly , the scale of the build ing work . The planning methods and the build ing measures can be de­rived trom this combination. The degree of in­tervention begins with the rebui lding of a struc­ture that no longer exists, or at best only as a ruin, includes complete demolilion and subse­quent rebu ilding , plus different levels of con­servation (trom renovation to gutting):

Reconstruction Restoration Deconstruction Demolilion Renovation/maintenance Repairs/maintenance Partial refurbishment Refurbishment Total refurbishment Conversion Gutting/rebuilding with partial relention

A1.1

We can add further terms to this list lor works that occur in conjunction with refurbishment but do notfit into this classification:

Modernisation Decontamination Extension/additions Fitting-out Change of use

In many cases more than one term appl ies toa building project because either the terms over­lap to a certain extent or several measures are carried out simultaneously. By contrast, the classification of the project si ze is re latively conc lusive. lt can be subdivided into live cate­gories:

XXL: town/district XL : blocklcomplex M: building S part of building/storey XS: dwelling/room

The expressions "further building work" or "works in the building stock" cou ld be used lor the class ification . Neither expression describes measures in the technica ! sense, but rath er in­dicates an approach . The former reflects the continuous processof bui lding: alter the con­version is also before the conversion . lt also makes it clear that every measure has to react to the existing structures. So strictly speaking "works in the building stock" should really be called "works with the bui ld ing stock".

Recenstructien

'ieconstruction is the rebuildmg of a structure :nat no langer exists , i.e. strictly speaking it is 'lew building work . In the case of a serious re­construction, however, use is made of old forms of construction, too. Reconstructions always in­. ,te contraversial discussions, with the criticism oecoming fiereer as the degree of actual recon­struction decreases, i.e. as faithfulness to the ori ginal diminishes. For example, whereas the olanning of the Stadtschloss in Berlin is being 'oll owed extremely crit1cally, the reconstruction o' Dresden's Frauenkirche met with much ap­oroval (Fig. A î .2). ~ lthough reconstructions are based on old de­signs, they are always new works without original oarts . The acknowledged regulations for new building works therefore generally apply. Stand­ards, statutory instruments, manufacturers' rec­ommendations, sequence of building operations, time on site, form of tender and site management

mostly correspond to those of new construction projects. The methods used during the planning phase arealso similar because only rarely are historie structures documented in such detail that the architect does not need to plan or de­sign anything new. Besides , many European , especially German, archives of drawings and documents concerning the bui lding stock were destroyed in World War 2, meaning that illustra­tions and/or photographs have to be used for reconstruction projects instead of engineers' and architects' scale drawings. During planning work, reconstruction means not only working through the available sourees for the original structure but also that today's architects have to mimic the building style of a certain period, i.e. it is not an exclusively scientific assignment. Contemporary specialist literature is an important aid through­out the planning when the goal is to reproduce historie construct1ons as accurately as possible using the means at our disposal today.

Definitions

A 1.2

Restoration

Restoration means f1nishing an incomplete structure. The term first appeared during the romantic period as people became aware of the cultural monuments of the past. lt was es­sentially coined by the French architect and art historian Eugène Viollet-le-Duc, who in the early î 9th century arranged for the restoration of palaces dating from the Middle Ages . Cologne Cathedra! is another example of a structure being completed alter almast 300 years of in­activity (Fig. A î .4). Restoration is very similar to reconstruction except that inthefarmer origi­nal building elements are still available, which are then supplemented by appropriate addi ­tions. lts close relationship with reconstruction means it is similarly disputed : "The processof restoration is a highly specialized operation. lts aim is to preserve and reveal the aesthetic and historie value of the monument and is based on respect for original material and authentic doe-

Planning werk required fer building Planning werk required in (M) cempared te new build' cernparisen teM {building) '

lé Ol ü5 QJ

Iu ro · c >

~.g> 0 0.

~ Q) 0. CLD <(

Recenstructien/resteratien ++

Demelitien/decenstructien n/a n/a

Renevatien/maintenance n/a n/a

Repairs/maintenance n/a n/a

Partlal refurbishment n/a

Refurbishment n/a

Tetal refurbishment n/a

Conversion +

Gutting/rebuild with part retentien +

Extensien

Fitting-out

Change of use

++ much more + more

a bout the same Ie ss

+

+ +

n/a +

much less n/a hardly or never

required

(/)

a; D c QJ f-

+ +

n/a

n/a

+ ++

+

+ +

++ ++

+

+

++ +-

nla n/a

eb (/)

0: Olc x ro ::J QJ c c 0 0. ~ ro u E E u ::J

ro 0 .0 2 ëil ~ 0 >-'ül 0 u "C

Q)

"Ö u 0 (Ü 0

ro i ö5 CL ëil ;;: QJ .:..i <( E x cij

+

+

+

+ ++ n/a nla

+ +

+

++ ++

+

+ + n/a n/a

nla

no comparison, cannot be evaluated (e.g. owing to major fluctuat1ons)

o, .<::: Qj E ;;: 0 0 2 cij x

n/a

n/a

+ nla

++

n/a

Costly, time-consuming planning because research is necessary

Often carried out by spec ial ised contractors

Costly, time-consuming organisation (When can work be carried out?) and accounting (many management services)

Costly, time-consuming organisation/accounts, often no planning services

Costly, time-consuming organ isation and accounting, frequently disputes with neighbours

Great demands placed on site management because of many uncertainties

In total slightly higher costslmore works reqd. at new/existing interface

High design costs due to adaptation tosuit the existing; h1gh construction costs

Extra costs for safety measures only

Measures in the existing account for only a smal! part of the total budget

Many partsof existing bldg. continue to be used; partlal fit-out; costly, costly, time-consuming organisation/accounts , often d1sputes w. neighbours

, Only an approval required, but can be very extensive

' Provides a guide as to how much higher the conversion surcharge must be or where it can be ignored.

2 Necessary increase in the conversion surcharge de pending on the size of the project.

A 1.3

11

Jefini tions

A1 4

~'llents. lt must stop at the point where conjec­:Jre beg ins ... " [1] - owever, this well -intentioned piece of advice soften disregarded , also because orig~na l doc­~'llents are frequently unavailable. Moreover, it s nol always possible to deduce what shou ld :::e c lassed as original : the first bu ild ing, the ' 'Si extension, the first refurbishment, or the '-st conversion? Th is conflict has pervaded the :J scussions surrounding th is subject in recent :Jecades and \he answers \end to refl ect the -espective zeitgeist inslead of being generally :;,cknowledged approaches. The reason for this ~1ay also be that the term "original" has been :-ansferred - wrongly- from the visua l arts to :'le discussions concerning arch itecture, where :'l iS ter'll was unknown.

Deconstruction

: was around the year 2000 when urban plan­~ ers rediscovered the theme of demoli lion as 'l egative building" and repackaged this in the

:s-m "conceptual deconstruction". What triggered : ~ s was the huge scale of the vacant housing

Trade Component

::enhworks Drainage Buried pipes and cab les

_:2dbeanng structure Al l components

=:e-oentry items Truss JOints All components

= :of covering Flat roof Pitched roof

- 2Eillng Boiler P1pes Rad iators and valves

= ~'llbi n g Hot-water provision

_ ecincs Circuit-breakers

- -e proteetion Smoke detectors Fire extinguishers Escape routes

·. ~dows Wooden w indows All w indows

-sJ ation Constructions w1th vapour barrier

:. ood-block flooring O lied surfaces

in the towns and c1ties of former East Germany fo llowing unification. But s1milar prob lems occur in other reg ionsas well; they are mostly the re­su lt of rad ica l, structura l processes that gi ve rise to an economie decl ine and hence the sudden departure of \he local 1nhabitants, e.g. in Detroit fol lowing the col lapse of car production there. Deconstructi on is intended to cure the urban problems of vacant properties th rough the lar­gel ed demoli l ion of ind ivi dual bu ild ings, blocks or districts , i.e. control the processof negative growth . However , theseconceptsoften fail be­cause of a lack of fundlng - demolilion without subsequent rep lacement with a new bui ld ing can never show a profil.

Demolilion

Besides deconstructi on on a large sca le, indl ­vi dual bu ildings are often demolished 1n order toerecta new structu re on the same site. This IS nol an orig1nal archi tectural servi ce because it is frequently carried out by spec ialist contrac­tors before the project development even gels fully underway. Demoli lion contractors are the

Inspeetion

Check for sand ing up and fl ush out , root damage Breakage due to sett iement and roots, sludge bu il d -up

Settiement cracks

Check bolts for tig htness Check for rot (sw1mm1ng poo ls etc .) and water damage

on ly ones with the appropriate specialist knowl­edge . Factors that need to be considered in add ition to the bu il ding regulat1ons (demol1tion permit) are structura l aspects (special demoli­l ion eng ineering), safety regulations for the site operati ves and the public (local residents and passers-by) and environmental proteetion meas­ures if any po ll utants or hazardous substances are invol ved . In Germany demolilion work has been covered by DIN 18007 since 2000.

Renovation/maintenance

Renavalion does not add anything new to the bu ild ing stock nor does it replace old with new. Inslead it maintains the value and the lunetion of the existing building through competent "up­keep". Renled premises are typically renovated . Germany's 2nd Ca lcu lation Act (Berechnungs ­verordnung ) speci fi es the following for this situ­ation: "Cosmetic repairs include only wallpa­pering, pa inti ng or wh itewash ing the wal Is and cei lings, the painting of floors, radiators and healing pipes plus internal doors and the inner surfaces of windows and external doors." [2]1 n

Interval

5 years 5 years

First inspect1on 5 years after comp letion

5 years 5 years

Gul lies, f lues, penetrations, remove growths, embrittlement cracking Gutters, downp1pes, visua l 1nspection of roof coverin g

Annual ly, at start of w1nter Annual ly, at start of w inter

Measure emissions Sludge build-up, seals- espec ial ly w ith automatic top -up Valves for operation and seals

Calc ification

Funct ion

Funct1on Check, refill Stared objects, wedged doors

Externa l proteel ive f1nishes Seals for bnttleness and c racks

Moisture

Care instructions: clean and oil

Annual ly, at start of w inter 5 years 5 years

5 years

Annual ly

Annual ly 2 years Continual ly

2 years 2 years

Once only 5 years after completion

Annual ly

s~ovation interva ls for renled apartments' K1tchens , bathrooms, showers 3 years 5 years 7 years

Li ving rooms, bedrooms, halls, toliets Other anc1 llary rooms

cccord ing to the model rental contract of the German Federal Min istry of Justice dat1ng from 1976, but these are not ri g id intervals.

12

- - - - ---'==

A 1.5

:'Ie same publ1cation, maintenance is defined as follows: "Maintenance costs are the costs :nat must be expended during the period of -'se in order to maintain the intended use and s'adicate properly the constructional or other Jefects caused by wear and tear, ageing and :.,e effects of the weather." Th 1s includes work :"at actually al ready fa lis under the heading of ~aintenance : "The minor maintenance meas­Jes cover only the rectification of smal I delects n the electricity, water and gas installations, :'Ie healing and cooking facilities plus window, :. ndow shutter and door hardware."

eglecting maintenance can lead to major damage, sspecially for those areas that are not generally . s1ble, e.g. flat roofs. The design team should :1erefore provide the building owner with a list J ' suitable maintenance measures logether with a schedu le of maintenance intervals and main­:enance instructions- a service that should be 'emunerated separately according to the Ger­"'lan HOAI scale of fees for arch itecVengineers. - he construction materials used should also be sted because , lor example, mineral paints for rnerior use are then only advisable when min­eral paints are used again in all subsequent ren­ovation work. Fig. A 1.5 shows a typical checkl ist :;i th the intervals at which the inspections or 'Tiaintenance work should be carried out.

Repairs/maintenance

Maintenance in this case is limited to the replace­ment or repair of detective building components. Maintenance work is necessary at reg u lar inter­vals between the total refurb ishment intervals and is usually the responsibility of the bu ilding manager, not requiring any assistance from the design team. Whether the maintenance work for identical building components coincides should be investigated lor economie reasons. A leak from a water pipe, lor instance, may occur from time to time, certainly not simply once a year. But in the case of regular leaks, it may be advisable to replace all the water pipes above basement level . The leak may indeed have been caused by earlier maintenance work, e .g. a system of iron pipework being partly replaced by copper. Maintenance measures inevitably lead to follow­up costs that may far exceed the actual cost of

the repai rs , e.g. if intact ceramic tiles have to be chiselled off when searching for the souree of a leak. In this case we must ask ourselves the question of whether we take the step to complete refurbishment, e.g. renewing all the bathrooms. In renled accommodation, the costs canthen be passed on to the tenants, at least partly .

Refurbishment

In contrast to maintenance, refurbishment measures also include intact but, for example, outdated components or surfaces. The differ­ence between refurb ishment and conversion, however, is that refurbishment does not involve any major changes to the loadbearing structure or interim layout. lt therefore lies exactly between maintenance and conversion, but the extent of refurbishment works can vary enormously.

Partial refurbishment Partla l refurbishment involves only one compo­nent or one part of the building, e.g. the facade , the ground floor or the east wing. Such projects are among the most difficult to organise because they are carried out whil e the rest of the build­ing is still in use. Confilets with users are inevi­table because partlal refurbishment measures cannot be carried out in isolation; the technica! infrastructure, for example, extends throughout the building. One effective strategy is to provide detailed information about the intended meas­ures at an early stage. For example, cutting and chasing workin occupied buildings is very annoying, especially when it starts at seven o'clock in the morning! A little consideration in the form of specifying working hours in the con­tract plus communications regarding the dura­tion of the buildingworkoffer some relief here: the work remains annoying but limiting the du­ration increases the acceptance. The same is true for setting up a scaffold, cutting off servic­es (espec ially the te lev ision !), workin internal and external access zones and all measures where excessive dust, noise or vibration is to be expected. More generous time and cost buffers should be allowed for when planning partial refurbishment in particu lar, also a budget to cover coll ateral damage to areas and components that were not included in the refurbishment plans. Such

Defin itions

A 1 .4 Cathedra I, Cologne (D), 1248/1880, Gerhard van Ri le/Ernst Friedrich Zwirner, Karl Eduard Voigtel

A 1 .5 Maintenance intervals (proposal) A 1.6 Panel construction building alter deconstruction,

Leinetelde (D), 1961 /2004, Siefan Forster Architekten

A 1.7 Conversion of a department store, Eschweiler (D), 2006, Bel Architekten

damage is unavoidable and its rectification should be carried out quickly and without bu­reaucratie fuss. In add ition, the owners of renl­ed premises should certain ly be warned about the possible risk of lost revenue from rents. For when the "suitability of the renled premises lor the use as staled in the contract" is revoked or reduced, German legislation permits rent reduc­tions of 20% on average. This clause comes into play as soon as an apartment cannot be ventilated because there is too much dust, or when the telephone in an office cannot be used because of excessive noise.

"Normal" refurbishment Normal refurbishment measures encompass an entire building or least a part of the bu ilding that already exists as a clearly separate , autonomous element. Any demolil ion work necessary is mostly limited to surfaces or preparatory work for upgrading fire protecti on, noise control or thermal performance. Additions and changes to the existing infrastructure are typical, but

AU

13

:::e' ini tions

- . 3

- . "J

A !tic storey convers ion, Munich (D), 2006, Andreas Meck, Susanne Frank Museum, Veenhuizen (NL), 2007, Atel ier Kempe Thi ll Conversion of an old courtyard , Munich (D), 2006, Auer + Weber, Peter Kulka Convers ion of a farmer briquettes iactory into housing, Frechen (D), 2007, ASTOC

:-s ' complete reptacement less common. Re­,_-:::; shment cycles lor individual components -:;. e been relatively wel I determined empirica!-- see "Piannmg refurbishment works", p. 23, =;; 3 1.2). True refurbishment without a change :'-se does not require building authority ap-: ·:.al and is safeguarded by the notion of tol­::·s: on of the building stock, but this concept is _s_a ly no longervalid fortotal refu rbishment or ::-. ersion works.

- : ::;;. refurbishment = :: ~:::> ti on measures during total refurbishment :·::_sets are very extensive. The demolilion re­:_·-s ne bui lding more or less to its loadbear­- ;: ::arcass . The primary structure remains es­:;::-: a ly unaltered. Typical measures include :-:; ::::::>mplete reptacement of the infrastructure s-:: :'Ie upgrading of all building components :: - eet the requirements of the latest legislation s-:: standards. Owing to the extent of the work, :::s ·efurbi shment is an expensive undertaking, ::s:: s::: ·ally when decontamination is involved as

_ 3ut in the end the refurbished building ::-ss very closetoa new one in termsof its ' s: : es and safety. This is also expressed by -- :; 'a:::t that upon completion all the compo-- :;- :s are covered by the warranty, a lso with ·::s:: ect io current standards and legislation. ::_:-a all-embracing warranty is aften miss­-;: ' ·::;rn simp Ie refurbishment projects because - :;-, components are left untouched, stil l in --:;·:x ginal condition. In termsof planning, a :::s ·e'urbishment rs not so very different to a

_ ::onstruction, partly because many uncer­:::: - : es are eliminated , so to speak. lt may be --:;: ::ertain weaknesses in the carcass , e.g. the s:• o' a damp-proof course, excessive deflec­- :: -s of ihe suspended floors, or acoustic weak-- ssses due toa low weight per unit area, remain ::::::=..Jse their rectification is uneconomic. During :- s :::; anning, the flatness tolerances should be ::-s oered.These usually lie welt outside those :' :::-·rent standards, which have been covered :, ::: \J 18202 supplement 1 only since 1969.

nversion

:::::- . ersions always affect the structure of a ::- ::; ng. They extend the concept of refurbish­- s- : :o interventions in the loadbearing mem-

4

bers and/or the interior layout. In conversion projects it is therefore always essential to appraise the existing loadbearing structure. Total refur­bishment measures almost always rnvolve con­version work, meanrng that many construction projects are best described by using more than one term, e.g. "total refurbishment plus conver­sion". Changes to the structure always require structural calculations, which must also take into account the existrng building fabric Th rs makes early, often destructive, investigations of the materials and methods used unavoidable, e.g. cutting open a concrete slab to establish the position and nature of the reinforcement Furthermore, true design services are necessary for conversion proJects because they involve changes to the interior layout or the access/ circulation concepts. Such additional planning input is covered in the German HOAI scale of lees for architects/engineers in the form of a surcharge for conversion work. Partial conve r­sion should be treated similarly to partia l refur­bishment.

Gutting/ rebuilding with partial retentien

Gutting comes close to providing a new build­ing. Ouite frequently the project involves retain­ing the facades of an existing building- resul t­ing trom a disputed understanding of the con­servation of historie bu ildings- but demolishing and rebuilding the interior completely.

Modernisation

The term modernisation is in the first place rele­vant in landlord and tenant legislation. Accord­ing to the German Civil Code, the annual rent may be increased by 11% of the costs incurred lor modernisation if the measures are carried out according to the statutory stipulations (in­cluding advance warning, detailed description of intended measures). Modernisation can add up to partial refurbishment, e.g. upgrading the thermal insulation or replacing windows, but also conversion work, e.g. the subsequent ad­dition of ba lconies. In any case, modernisation serves to imprave the lettable floor space by increasing the level of comfort or decreasing the running costs. The fol lowing measures are

A 1.9

c;;:::·::s:J as modernisations in the meaning of ::;-c;-::~ andlord and tenant legislation:

_::: :;:·a:J,ng thermal/sound insulation , a lso in­·-c; -~:: _. e.g . between stairs and apartments)

-= san1mry fac ilit ies ~:;:::: al1on of central healing (to rep lace indi­::~a appliances) or central hot-water supply ~:;:sao of separate water heaters)

- :::::ons to electncal installations, also the :::-:. s on of cable televis ion or the instal lation : ' a Joor intercom -~::: erection of balconies or conservatori es -:;:a ng a li ft

J:econta mination

-- :; s :ne proper eliminatien of pollutants and - =-::::·:Jous substances from bui ldings and their ::··a:::: disposal. The contam i nation of the inte­- :-a- oy hazardous substances has been a : :-s:ant topic in refurbishment since the late · ~ - :::s due to the presence of PCP-based wood : ·-c;sarvatives and asbestos ti bres. In the mean­- -s. :'le ri sks of many other substances have :::s:::::'Tle known; the opti ons for deal ing wi th ·~sse are discussed in the chapter on hazard-: ~s substances (see pp. 102- 115). Various :::a:J ory instruments and different limit values -c;, s; depending on the use of the building: the - ax mum workplace concentration, lor instance, s aoplied to commerc ial uses, recommended a ues I and 11 of the Environmental Issues

:::::::"'lmittee, on the other hand, are re levant lor ~::" s 1ng and public buildings. 11 the values es­:aol shed in measurements of the interior air sxceed the prescribed limit values, decontami ­~a:~on must be carried out, which can take place :::e'ore or during the building works. For the :::Jilding owner, such decontamination measures :::'ten result in higher costs and a substantial in­::::rease in the time needed lor the work. Carry­ng out measurements wel I ahead of any pro­oosed bui lding works is therefore imperalive :;here hazardous substances are suspected. In ouildings bu iltor refurbished between 1960 and 1990, the chance of find ing contamination s relatively high.

Extensions/additions

An extension is a new structure that is directly conneeled with the use of the existing building . The plann ing work should consider the tact that conversion work at the ju netion with the existing build ing is usually unavoidable and therefore structural issues are involved . A frequent cause of problems is the difierential settiement that can occur between the old and new parts of the bui lding , espe:::ia lly in the following cases:

Different foundation levels Building the foundations lor the new works in the region of the previous excavat1on Building the foundations in different soils Add ing extra storeys to only part of the exist­ing build ing (subsequent settl ement) Dewatering measures lor the new works, e.g. lowering the water table

Fitting-out

Fitting-out is all the works carried out after erect­ing the structural carcass plus roof structure and roof covering. One typical measure is con­verting the roof space into one or more habit­ab le rooms, i.e . f1tt1 ng-out an att ic storey not originally in use. The constructional problems that can occur are descri bed in the chapters "General refurb ishment tasks" and "Buildings of the founding years" (see pp. 127-129 and p. 153). Added tothese are the loss of protee­tion afforded by the notion of tole ration of the building stock, which complicates the building authority approval process, espec ially with re­spect to lire protection , means of escape, dis­tanee to neighbouring buildings and car park­ing requi rements . Further probl ems resul t trom the tact that the work has to be carried out while the rest of the building is occupied (see "Partial refurbishment" , p . 13) . Such fitting-out proJects are therefore very demanding trom the plann ing point of view and should be remuner­ated accordingly .

Change of use

A change of use is subject to construction legis­lation sti pulat1ons. In the first instanee thi s con­cerns obvious changes like converting an apart­ment block into offices, even if only part of the building IS involved. However, also minor changes of use within the same usage group, e.g. from

Definit ions

A 1.10

baker to hai rdresser, require approval by the authorities in certain cases, and especial ly when there are differences wi th respect to occupa­tional safety and health issues, emissions, car parking , etc. For this reason, more intensive uses represent changes of use that requ ire approval, e.g. if an existing office floor used as a company headquarters is let to a cal I centre operator . One prob lem here is the associated loss of proteetion afforded by the notion of toleratien of the bui ld ing stock. Th is means that a change of use can have far-reach ing conse­quences because the current bu ilding regu la­tions may need to be camplied with, and the existing building may not be adequate. This legal situation has been cr iti cised many times because it hinders the long-term use of bu ild­ings and is hence questionable in termsof both econom 1cs and ecology.

Notes:

[ 1] The Venice Charter, 1964 [2] Zweite Berechnungsverordnung , cl. 28

AU 1

15