Protecting a Historic Structure during Adjacent Construction

8 Pages·2001·0.76 MB·English

by  Randl, Chad

ClemsonUniversity
29.84/3-5:3 RESERVATION
3 1604 014 760 229
Tech Notes
U.S.DepartmentoftheInterior
NationalParkService
CulturalResources
HeritagePreservationServices
TEMPORARY
PROTECTION
NUMBER
3
Protecting a Historic
Structure during
Adjacent Construction
Chad Randl
Technical Preservation Services
National Park Service
IDENTIFYING AND AVOIDING RISKS
FROM ADJACENT CONSTRUCTION
Valued for their ability to convey the steel beam to be dropped from a con-
past through existing materials and fea- struction crane onto its roof, significant
tures, historic buildings must also sur- damage may occur. Additionally, adja-
vive in an ever-changing present. That cent construction work can expose the
change is often characterized by new neighboring historic building to con-
building construction and demolition centrations ofdust, vibration and fire
activities on neighboring sites. Whether hazards that would normally be experi- FEDERAL
PUBUCATtON
it is the modest renovation ofan exist- enced only overthe course ofmany
ing building or the demolition ofan years.
existing structure and construction ofa These concerns are often overlooked
new high rise, physical damage to an when aproject is undertaken nextto
adjacent historic building may occur. historic resources. In some situations,
It is important forboth the historic the historic property manager may be PUBLIC DOCUMENT^
property owner and those responsible unaware ofthe nature andextentof DEPOSITORY ITEM
for the neighboring work to give care- work at an neighboring site. In other
ful consideration to the potential risks. cases, the new construction team is not AUG
2 2001
Early planning offers the opportunity familiarwith the particularly fragile
to identify these risks and to determine characterofthe neighboring historic CLEr^GN
successful ways to avoid them. structure ordecides to repairany dam- LIBRARY CMi
age afterthe factratherthan avoiding it OO
Problem fromthe beginning. CON
The forces that contribute to the deteri- Solution o1
oration ofa historic building, from o
atmospheric pollutants to the footsteps Effective planning and protective mea- CM
ofvisitors, often take decades and even sures initiated before construction takes When historic structures are
centuries to exacttheir toll. Demolition place can prevent most ofthe damage
activities and new construction on that may occurto adjacent historic exposed to adjacent construction
neighboring sites, however, can cause buildings. Depending upon the nature ordemolition work, aprotective
immediate harm to the physical integri- ofthe project, protective measures may plan including documentation,
ty ofa historic structure. In the instant be limited to documenting and moni- monitoring andspecific safeguards
it takes an improperly planned excava- toring the historic structure or may
tion blast to crack the foundation ofan encompass a broader plan that shouldbe implementedtoprevent
adjacent historic structure, or for a includes encasing windows, indepen- damage and loss ofhistoricfabric.
dent review ofexcavation procedures resources. The ultimate goal is to draft process. The support ofneighborhood
and a range ofother precautions. a protection plan acceptable to both committees, local non-profit preserva-
Cooperation between all parties can parties. tion organizations, independent engi-
help to ensure that construction activity Resolving concerns before construc- neers and the historic district commis-
continues without interruption and that tion is underway can save time and sion (ifapplicable) may be enlisted
the neighboring historic building is money, as well as the need to repair to ensure that protection concerns are
preserved unharmed. damaged historic fabric. It is crucial fully addressed. The developer will
The information provided in this that such discussions take place during benefit from the assembly ofa team,
Tech Note can serve as abasis fordis- the paper stage ofthe project, before including or representing the general
cussions between the historic property final decisions are made. Ifnot, the contractor, architect, structural engi-
manager and the developer ofthe adja- developer may conclude that changes neer, construction manager, and sub-
cent site aimed at ensuring the protec- would be cost prohibitive and that it is contractors, who can be present at
tion ofthe historic building in a cost- preferable to repairdamage after it consultation meetings and play a con-
effective manner. This guidance is also takes place. Early consultation also tinuing role in balancing protection
applicable where new construction is provides information that can be used efforts with development interests.
undertaken on the same site as the his- to assess whether the level ofinsurance Preconstruction meetings should
toric structure. coverage is sufficient to meet the spe- address several issues. Most impor-
Although adjacent construction cific project risks. tant, the parties should reach an under-
work often poses a more immediate The owner ofa historic property standing about what steps will be taken
threat than the incremental impacts of cannot in most cases compel the sup- to protect the historic structure {seefig-
weather or pollution, the best defense port and cooperation ofthe develop- ure 1). Responsibility for implement-
forboth situations is that buildings be ment team. If, after consultation has ing the agreed upon protections should
in good condition. Awell maintained been attempted, the level ofprotection be established among the developer,
structure with tight mortarjoints, provided is not sufficient, the aid of the general contractor and relevant sub-
strong connections between interior local building officials should be contractors, and the historic property
and exterior walls, solid foundations sought. Local building officials, owner. Such decisions should be listed
and sound plaster is at less risk from through the permitting process, can in performance specifications that
neighboring activity than a neglected often insist that changes be made to accompany agreements between the
structure. development plans to ensure that adja- contractor and the developer. Awalk-
Providing adequate protection cent properties are protected. Local through ofthe historic building by the
involves the following steps: 1. consulta- building codes may alsoprovide safe- development team is also advisable.
tionbetween the historic building owner guards by establishing certain conditions Finally, schedules for major work such
anddevelopment team to identify poten- such as maximum vibration levels. as excavation, and requirements for
tial risks, negotiate changes and agree Otherparties can also participate in materials delivery, site storage, and
upon protective measures; 2. documen- and contribute to the consultation other use ofthe premises by the con-
tation ofthe condition ofthe historic
building priorto adjacent work; 3.
implementation ofprotective measures
at both the construction site and the
historic site; and 4. regular monitoring
during construction to identify damage,
to evaluate the efficacy ofprotective
measures already in place, and to iden-
tify and implement additional correc-
tive steps.
•SomO WIK1DC*J ftetfTtCflOK)
Consultation
Early consultation between the historic Low &OOP
property owner and the developer of SQftbfcUfcCa &j
T^
the neighboring construction site is the Smuttier
first and often most important step. &rrrgfc<sfcg>
Establishing such contact has many
advantages. Consultation provides the
foundation for a mutually beneficial
relationship that is cooperative rather
than adversarial. The process gives the
historic site owner an opportunity to
become familiar with the scope ofthe
S^
impending project and for the develop- ?7.
ment team to understand the historic
structure's vulnerabilities. Consultation
permits all parties a chance to propose,
discuss, and negotiate changes to the Figure 1.Before newconstructionwas undertaken totheleftofthischurch,asubcontractorwas
construction plan that reduce the risk hiredtodesign aprotectivesystem forthetile roofandclerestorywindows. Drawing:Alan Shalders,
ofdamaging adjacent historic Universal BuildersSupply,Inc.
tractor should be discussed and close-up images ofcracks, staining, directly adjacent to and sharing a wall
arranged to minimize disruptions to the indications ofsettlement or other frag- with the historic structure. Other fac-
historic site. ile conditions. Acomplete interior and tors influencing the degree oflikely
exterior crack survey should be under- impact include the age, construction
Documentation taken to identify and characterize exist- type and structural integrity ofthe his-
ing cracks (seefigure 2). Their loca- toric building, as well as the depth and
Acrucial step following consultation tions can then be plotted on a drawing makeup ofits foundation and its sur-
with the developer is to document the ofeach wall or ceiling surface. While rounding soil types.
existing condition ofthe historic struc- identifying every hairline crack may be Owners should also anticipate the
ture. Such an investigation provides a impractical in a large building or one effect increased dust, vibration and fire
"baseline" from which changes to the that exhibits a great deal ofpreexisting risk will have upon interior architectur-
building during the adjacent construc- damage, the more thorough the docu- al features and furnishings. For the
tion can be identified, monitored and mented record, the better. The condi- most sensitive objects, such as chande-
assessed. Like the consultation tion offeatures such as arches, chim- liers, paintings and glassware, tempo-
process, thorough documentation bene- ney stacks and parapet walls deter- rary removal to an off-site location
fits both the historic property owner mined by the engineerto be particularly may be the safest course. Those fea-
and the developer. For the former, it susceptible to distress should also be tures that cannot be easily removed,
may be used to substantiate claims that recorded even when no damage is including plaster ceiling medallions
damage occurred as a result ofthe apparent. and cornices, can be cushioned and
neighboring construction work by illus- buttressed by padded wood supports.
trating the previously sound condition Common Risks and Additional information concerning the
ofthe historic building. Ifthe damage Protective Measures safeguarding ofinterior features can be
existed prior to construction work, the found in the preceding Tech Note in
record can show that it was not caused Each instance ofnew construction or this series, "Temporary Protection,
by the developer's negligence. In the demolition next to an existing historic Number 2. Specifying Temporary
case offuture litigation, the documen- structure will involve varying risks to Protection ofHistoric Interiors During
tation record can serve as evidence that structure. The proximity ofthe his- Construction and Repair."
along with the testimony ofthe profes- toric site to the project and the scope of The remainder ofthis section
sional who undertook the assessment. the project are two ofthe most signifi- addresses some ofthe more common
Both parties should ensure that the cant variables. Construction ofahigh dangers to historic structures when new
documentation is objective and accu- rise building with deep foundations is construction or demolition activities
rate. Joint surveys, in which both the more likely to affect a neighboring occur nearby. The description ofeach
developer and the historic property structure than the rehabilitation ofa potential impact is accompanied by
owner participate or sign offon noted nearby rowhouse. However, the con- suggested approaches forreducing or
conditions, are most likely to ensure verse may be true ifthe rowhouse is eliminating those risks.
that the resulting data are not in dis-
pute. When the developer pays for the
assessment, it is advisable that an inde-
pendent professional be hired and that
the survey results be accessible.
Information obtained through docu-
mentation can also be used in formulat-
ing a protection plan for the historic
building. By characterizing existing
damage and exposing potential weak-
nesses, the documentation process
identifies areas ofthe structure that
may require additional protection as
well as appropriate locations for moni-
toring equipment. Features that should
receive particularattention during visual
inspections would also be highlighted.
Although a formal building condition
survey including analysis, repair pro-
posals and cost estimates is not neces-
sary, the property owner may find that
the disruptive period during adjacent
work provides an opportune time for a
thorough survey program.
Documentation ofexisting condi-
tions should take the form ofwritten
descriptions, 35mm colorphotographs Figure2. With advanced noticeofadjacentconstruction activity,acrackmonitorcan beusedto
and/ora videotape recording. determinewhetherexistingcracksin thehistoricbuildingarestableorstillexperiencingmovement.
Photographs should show both the Comparedwith measurementstakenduringthemonitoringphase,such informationcan helpdeter-
interiorandexteriorofthe building, with mineifsubsequent movementresultedfrom workonthe neighboringsite.Photo:Avongard Products
U.S.A.,Ltd.
Vibration building. New construction almost adjacent building. Drainage mecha-
invariably calls fordigging a founda- nisms may also become inoperable
Demolition and new foundation work tion that is much deeper than the foun- when excavation workers inadvertently
are common sources ofvibrations that dations ofneighboring historic build- seal offor collapse old pipes running
can affect adjacent structures. The ings. This is especially true for pro- from neighboring buildings. Ifblocked i
tools and methods used in demolition, jects that include underground parking pipes cannot remove water from both *
such as impact hammers, wrecking facilities. A historic structure, with a above and below the surface ofan his-
balls, pavement breakers and implosion shallow masonry or stone foundation toric site, excessive moisture levels or
blasting, produce vibrations that may and wall footings, may experience cor- flooding may result.
be transmitted to the historic structure. responding displacement that can result Regular visual inspections (part of
Similarly, techniques used to prepare in major structural damage. the monitoring program described
new foundations (pile driving and Efforts to control movement should later) are one ofthe best means of
blasting) create potentially dangerous begin during the consultation phase. thwarting increased moisture levels.
vibrations. Vibrations may also be Whether the developer's engineer The inspection procedure should
caused by increased truck traffic selects underpinning or strengthened include checking gutters, valleys and
accompanying new construction or excavation walls with tie backs as the exposed drains for any obstructions.
demolition work. In all cases, the means to resist movement ofthe adja- Also, indications ofdampness or water
force ofthe vibrations reaching the cent structure, the historic building damage in the basement and where
adjacent historic structure depends team should retain its own engineer to gutters and downspouts meet other
upon the activity generating the vibra- review the plans (seefigure 3). The building surfaces should be noted.
tions, the distance between the source consulting engineer should ensure that Construction site runofffrom
and the existing structure, and the type the selected approach addresses the cement mixing and cleaning and dust
ofsoil or pavement found between the unique characteristics and vulnerabili- suppression activities should not flow
two. ties ofthe historic structure and that toward the historic property. Although
Historic structures may be particu- even incidental movement is restricted. placing screens and wire cages over
larly vulnerable to the effects ofvibra- exposed areas ofthe drainage system
tions generated at an adjacent site. Water may provide some protection from
Deferred maintenance and past alter- obstructions, such installations need to
ations may have produced structural Awell functioning water drainage sys- be inspectedjust as frequently. Low-
weak points that are susceptible to tem is essential to the protection ofany pressure water washes can occasionally
damage. Historic finishes, such as historic structure. This system can eas- be used to flush the system ofdirt and
plaster walls and ceilings, lack the ily be rendered ineffective by neigh- debris. To reduce the possibility that
flexibility to accommodate abnormal boring construction or demolition drainpipes will be blocked at the adja-
movement, while shallow foundations work. Debris originating at the con- cent construction site, all concealed
(common in historic buildings) may struction site often finds its way to the pipes should be traced from their ori-
lack the rigidity to resist vibration gutters, downspouts and drains ofan gins at the historic structure and the
induced movement.
Mitigating the effects ofvibrations
should begin during the consultation
process when acceptable levels can be
set and alternative processes explored.
Hand demolition is an appropriate sub-
stitute when conventional demolition
activities may cause excessive vibra-
tions. Ifpile driving is likely to dam-
age adjacent structures, the contractor
may be able to employ non-displace-
ment piles that are inserted in bored
holes rather than driven. Lower vibra-
tion levels can also be achieved by
"jacking-in" orpressing the piles into
the ground. Locating delivery entry
and exit points farther from the historic
site may reduce vibrations caused by
increased vehicular traffic. Once con-
struction is under way, continual crack
and vibration monitoring provides an
effective warning system, indicating
that established safe thresholds have
been crossed.
Figure3. Concretepierunderpinningtoanexistingbuildingmaybenecessarywhen adjacentcon-
Movement structionoccurs. In thisexample,pitsarehanddugbeneaththefoundationofthe historic building
toprovidespaceforwood forms. Afterconcreteispouredintotheforms,thespacebetween thetop
ofthepierandthebottomoftheoriginal foundation is packedwith a quicksettinggrout. Thehis-
Excavation and foundation work can toricbuildingownershould retain an independentengineertoensurethattheunderpinningplan
also cause ground displacement and adequatelyprotectsthehistoricstructure. Photo: ProfessorArpad Horvath,DepartmentofCivil
movement ofan adjacent historic and Environmental Engineering,UniversityofCalifornia,Berkeley.
4
information passed on to the appropri- alarm system, that system shouldbe age, windows should be covered with
ate contractors. Final landscaping and upgraded to protect rooms that are ren- plywood. Layers ofcushioning materi-
grading patterns on adjacent construc- dered accessible from the outside. In als can be placed between the plywood
tion sites should be examined to ensure cases where the historic structure does covering and particularly fragile win-
that rainwater is not routed towards the notdirectly abut new constructionor dows, such as stained glass. Ifentire
historic building. demolition activity, attention should still wall surfaces are vulnerable, scaffold-
In some cases, the lack ofwater be paid to the possibility that incidents ing should be erected against the
beneath an historic structure can lead ofvandalism and theft will carry overto facade and debris netting placed on the
to damage. Buildings located in areas the historic site. outside ofthe scaffolding. Plastic
with a high watertable were often con- sheeting can provide added protection
structed upon timber piles. When Physical Impact in areas where acidic cleaning solu-
groundwater or storm water is removed tions may splash onto historic facades,
from a neighboring site during founda- Construction or demolition can cause windows and other surfaces.
tion excavations (a process known as direct physical damage to neighboring The best means ofprotecting a his-
"dewatering"), the groundwater level historic features and materials. Cranes, toric structure from physical impact,
beneath the historic site may also drop. hoists and workers on upper floors ofa however, is often to have adequate hor-
Previously submerged timberpiles that construction site can drop building sup- izontal and vertical netting and barriers
are exposed to air can quickly begin to plies and tools onto an adjacent historic in place at the construction site. When
undergo dryrot. Ifthere is reason to structure. Misdirected debris chutes adjacent buildings are adequately con-
suspect that the structure was built on and backing vehicles may also leave sidered in the construction site netting
such a foundation, the property their mark. and scaffolding plans, protective mea-
manager should work with the neigh- Generally, to counter these occur- sures at the historic site can be less
boring construction team to maintain rences, protective barriers are placed intrusive, and the likelihood ofdamage
the existing water table. This can be over any area ofthe historic structure reduced even further.
done using watertight excavation sup- deemed at risk. Ifthe new construc-
port systems such as slurry walls which tion will rise above the historic build- Additional Dangers
ensure that most ofthe water pumped ing, plywood sheets should be placed
out ofthe construction site does not overthe roofto distribute the force of Other byproducts ofnew construction
come from adjacent properties. dropped materials (seefigure 4). and demolition, such as dirt and dust,
Dewatering ofsoft clay ground may Plywood covers should also be placed can also pose threats to an adjacent his-
also result in settlement ofa neighbor- overdecorative roofembellishments toric structure. Dust suppression mea-
ing building, as ground water pressure such as finials and balustrades. sures including the installation offab-
is reduced and the soil consolidates. Alternately, horizontal netting can be ric enclosure systems should first be
rigged to shield vulnerable rooftop fea- employed at the building site (seefig-
Fire and Security Concerns tures. ure 5). Despite these efforts, historic
Facades that are directly exposed to building owners will undoubtedly have
The heightened possibility offire adjacent construction sites should to deal with raised levels ofdust infil-
accompanies many demolition and new receive close attention. To avoid dam- tration. Accordingly, vulnerable interi-
construction activities. Temporary
heating devices, torches, sparks,
molten metal and undersized electrical
utility panels are some ofthe most
common sources offire at construction
sites. Additionally, the improper stor-
age offuels, cloth rags and brushes ^'
also presents opportunities for fire to l
ignite and spread. The Tech Note,
"Specifying Temporary Protection of WW
Historic Interiors during Construction
and Repair," provides detailed informa-
tion on reducing the likelihood offire
in situations involving work near his-
toric structures.
The security ofa historic building
can be threatened when adjacent con-
struction provides opportunities for
illegal entry. Newly constructed floor
levels at the building site may make
the neighboring historic structure's I
ledges, windows and rooftops accessi-
ble to trespassers. Window openings
on the historic building should be fas- UhJkJiM,
tened and all doors from the roofto the
interior should be locked. Where ahis- Figure4. Droppedequipment,tools,andmaterials all present riskswhen newconstruction rises
toric structure is protectedby an intruder aboveneighboringhistoricstructures. Inthiscase,thehistoricslate roofwascompletelycovered
with sheetsofexteriorgradeplywood. Photo: National ParkServicefiles.
basement floor. More comprehensive
measurements can be obtained by
locating sensors at several points
throughout the structure and the ground
immediately adjacent to the historic
building foundation (seefigure 6).
»»»/ Whether acceptable vibration levels
are mandated by law or left to the dis-
cretion ofa project engineer, thresholds
should take into account surrounding
soils, the makeup and condition ofthe
adjacent foundation and the particular
vulnerabilities ofthe historic resource.
Construction projects that involve
major excavation work next to historic
structures should include a program of
iff test blasting before work begins.
I
Testing various charges, delays and
blast design configurations will aid in
liJJBif
developing a controlled program that
limits blast induced damage to a neigh-
n iu I oo boring property.
rr FF Structural movement as described in
the preceding section is detected and
Figure5. The historic buildingontheleftispartiallyprotectedfromdebrisanddustgeneratedby recorded using a number ofdifferent
therenovationofthestructuretotheright. Suchtemporaryenclosuresystemsconsistofapolyeth- tools. Electronic monitors that feed
yleneorotherfabricshellstretchedbetweenanaluminumframe. Photo:WaltonTechnology,Inc. precise movement measurements to
laptop computers can be placed across
existing cracks (seefigure 7). When
or objects and artifacts should be cov- Monitoring budgets are tight or a large number of
ered ortemporarily moved to another cracks are involved, inexpensive tell-
location. Windows can be taped shut A monitoring program should be estab- tales made from two sheets ofoverlaid
ortemporarily sealed with clearpoly- lished during the consultation and plastic with a grid can be used to track
ethylene sheets. Additional mats or documentation phases and continued changes.
carpets near entrances can help reduce until adjacent work is finished. It is Optical survey instruments provide
the amount ofdirt tracked inside. An undertaken to detect, gauge, record and another means ofdetecting vertical and
accelerated maintenance program that interpret structural movement, the lateral movement within a historic
includes thorough and frequent clean- effects ofvibration and other changes building. Control points are estab-
ing and HVAC filterreplacement, is an to the historic building that result from lished and marked by targets orreflec-
effective means ofaddressing the neighboring construction or demolition tors on the historic structure facade and
degraded environment surrounding a work. Datacollected during the moni- > interior walls before adjacent construc-
construction site. To lessen the chance toringprogramcan serve as abaseline tion begins. The location ofeach of
ofairborne asbestos infiltration, the forany subsequent movementor these markers is precisely measured at
exhaust from sealed work areas must changes to site drainage patterns that regular intervals. Engineers then use
be properly filtered and vented away arise within the first years afterconstruc- the resulting information to determine
from historic buildings. tion is completed. Ultimately, monitor- whether the markers have shifted from
The owner ofa historic property ing shows the degree to which steps their original positions and, ifso, the
should anticipate the increased rodent taken to protect an historic structure rate and direction ofmovement.
and pest presence that accompanies from adjacentconstruction are sufficient Aprogram ofvisual inspections
major demolition activity. Newly and successful. undertaken by a qualified conservator
opened holes in old foundations are Because ofliability concerns, those orengineer is an important adjunct to
easy escape routes that should be responsible for a new development will technical monitoring procedures.
promptly sealed. The construction or often arrange to monitor an adjacent Inspectors should look for newly
demolition site rodent control plan structure. As with a documentation opened cracks, other signs ofsettle-
should include provisions for protect- program, the historic property owner ment and movement, and evidence of
ing adjacent historic resources. may want to hire an independent engi- increased dampness or water infiltra-
Concurrently, the historic property neer to review both the monitoring tion. Additionally, visual inspections
owner should consider securing a con- process and the measurements that should ensure that temporary protective
tract with an independent extermina- result. coverings are secure, that dust and dirt
tion company. Plans should include The extent ofthe monitoring pro- are not accumulating in the historic
both preventive measures to reduce gram and the tools used will depend building, and that fire and hazardous
conditions favorable to infestation as upon the scope ofthe adjacent activity. material protection provisions are
well as a system oferadication such as Abasic plan to address concerns over being upheld. Achecklist can be
rodenticide and traps. vibration levels may include a single drawn up during the consulting and
seismograph placed on the structure's documentation phases for use during
each visual inspection. Such a
'Hi
systematic written record may also
prove useful ifdisputes arise overthe
timing ofand responsibility fordamage.
Conclusion
Protecting a historic building from
adjacent construction or demolition
activity requires thoughtful planning
and cooperation between the developer
and the historic property owner.
Thorough pre-construction documenta-
tion ofthe historic structure ensures a
common understanding ofpresent con-
ditions and suggests appropriate dam-
age prevention measures that can be
taken at both the historic site and the
construction site. Aroutine program of
visual inspection and vibration and
movement monitoring helps insure
early detection ofthe effects neighbor-
—
~,'^-^6 ing construction work is having on the
1 ' ./ historic building. Early consideration
ofthese issues, before damage takes
place or worsens, can allow for the
Figure6. Aseismographrecordsvibrationstransmittedatthegroundlevelofanhistoricbuilding. adoption ofsafeguards that protect the
Theinstrumentiswiredtoalightandsirendesignedtowarntheexcavationcrewthatvibrationlevels developer's schedule and budget and
areapproachingpresetlimits.Additionalsensorsareofteninstalledinthebasementandonsensitive the physical integrity ofthe historic
featuressuchasstainedglasswindows. Photo:Wilson,Ihrig&Associates,Inc. structure.
50
Figure7. Electroniccrackmonitorandsurveytargetsareshowninstalledon anexistingwall. Thecrackmonitorfeeds movement
datatoalaptopcomputer. Thetargetsarealigned and measuredwith optical surveyequipmenttodetermine thedegreeand
direction ofmovement. Photo: McMullan andAssociates,Inc.
Checklist for Historic Property Owner and Historic Site
Consultwithdeveloper, andotherpartiestodetermineextentofwork andidentify necessaryprotective measures
mm
Conduct survey ofexisting conditions, including 35 photographs, crack inventory and description ofother damage
Include historic building in construction site fire plan
Secure windows and rooftop doors that are made accessible by new construction
Remove particularly fragile interior objects and furnishings from site
Install temporary supports beneath fragile features that are not moved
Place plywood coverings on openings that face construction area
Ifadjacent construction rises above historic site, protect roofwith plywood covering, encase rooftop embellishments
D
Ifconstruction is directly adjacent, coverhistoric facade to protect against mortar and acidic cleaning solution
Install temporary floorcoverings at entrance and seal windows facing construction site to limit dust infiltration
Remove dust from interior surfaces on accelerated schedule
Clean HVAC system & filters on accelerated schedule
Clear obstructions from gutters and drainage system regularly
Establish monitoring program, including:
1) Seismographs to ensure that effects ofblasting, pile driving and other work are at acceptable levels
2) Crack monitors and optical survey methods to detect movement
3) Schedule ofregular visual inspection
Checklist for Development Team and Construction Site
Consult with historic property owner and otherrelevant parties to identify necessary protective measures
Review and sign offon pre-construction condition survey ofadjacent property
D
Arrange delivery locations and times to limit disruption and possible damage to neighboring historic structure
Explore excavation and demolition methods that produce low vibration levels
Limit movement ofadjacent building with sufficient underpinning orreinforced excavation walls
D
Reduce changes to adjacent ground water level during dewatering
Ensure waterrunoffis not directed toward historic structure
Install appropriate debris nets to prevent dropped materials from impacting historic building
Direct debris chutes away from historic structure
Install fabric enclosure system to reduce spread ofconstruction dust
Include adjacent historic building fire plan and ensure fuels, rags and brushes are stored appropriately and not directly
adjacent to historic site
Ifasbestos orlead remediation is involved, ensure exhaust from sealed building is filtered and vented away from his-
toric site and that lead chips are gathered and removed
Include adjacent historic structure in rodent control program and seal openings in demolished foundation
Participate in monitoring program at historic site to ensure that vibration levels or indications ofmovement are within
established thresholds
This PRESERVATIONTECH NOTE was preparedby the National PRESERVATIONTECH NOTES are designed toprovide practical
Park Service. Charles E. Fisher, Heritage Preservation Services, information on traditional practices and innovative techniques for
serves as theTechnical Editor. Special thanks go toDeborah Slaton successfully maintaining and preserving cultural resources. All
and Michael J. Scheffler, P.E., ofWiss, Janney, ElstnerAssociates, techniques and practices described herein conform to established
Inc., Sharon Park, KayWeeks and MichaelAuerofthe National National Park Service policies, procedures and standards. ThisTech
Park Service's Heritage Preservation Services, and Marie Ennis of Note wasprepared pursuant to the National Historic Preservation
Einhorn Yaffee Prescott fortheirreview and comments. Thanks Actwhich direct the Secretary ofthe Interiorto developand make
also go to Denis McMullan, McMullan andAssociates; Richard available to government agencies and individuals information con-
Ortega, PE, OrtegaConsulting; Dorothy Richter, Hager-Richter cerning professional methods and techniques forthe preservation of
Geoscience, Inc.; George Siekkinen and Gregory Mixon, National historic properties.
Trust forHistoric Preservation; Suzanne Pentz, Keast & HoodCo.;
Mark Richards, MoretrenchAmerican Corporation; Dr. EdwardJ. Comments on the usefulness ofthis information are welcomed and
Cording, Department ofCivil and Environmental Engineering, should be addressedto PRESERVATIONTECH NOTES, Technical
University ofIllinois; Mark Gaudschaal, Schnabel Foundation Co.; Preservation Services NC200, National CenterforCultural
William Stivale; Robert M. Powers, Powers andAssociates; Martin Resources, National Park Service, 1849 C Street,
P. Azola,Azola andAssociates; and Margaret Gardinerand Mary NW. Washington, DC 20240.
Knapp at Merchant's House Museum, fortheirassistance. Tim
Buehner, National Park Service, andCamille Martone provided ini- ISSN: 0741-9023 PTN42 July 2001
tial research forthis publication.