Guidelines For Roofing

Standing SeamApproved for allbuilding types5-V Crimp Approvedonly for sheds,garages and someresidentialCorrugatedApproved only forshed, garage,commercial,overhangsApprovedonly for Non‐ContributingcommercialR-PanelIf the roof is generally rusting, splitting, pitted, severelybuckled or warped, or many of the seams or edges areopen or disfigured, replacement of the roofing might bewarranted. If considering replacement, applicants areencouraged to make every attempt to match seampatterns and color with the replacement material.Typical localized problems and possible repairs for metal: Worn paint, galvanizing or coating – Repaint Slipping sheet, panel, open seam or solder joint –Refasten and/or re‐solder Isolated rusting or holes – Replace to match originalMetal Roof ReviewReplace in‐kind with metal roof material of samematerial and designHDLC Staff review.Replace copper roof with other materialCommission appeal.Install standing seam metal roofingRib-Panel Approvedonly for Non‐ContributingcommercialHDLC Staff review.Install corrugated metal roofing at sheds,garages, commercial buildingsMETALHDLC Staff review.Metal was popularized for roofing after sheet metalproduction was expanded following the mid 19th century,and can be found on commercial and industrial buildings,as well as residences and outbuildings. Traditional sheetroofing metals include lead, copper, zinc, tin plate, ternplate and galvanized iron. Many metal roofs requireregular painting with traditional colors including silver,grey or green to minimize the potential for corrosion.Install 5‐V crimpOn shallow pitch roofs like galleries, porches, cupolas ordomes, small rectangular pieces of flat seam metal roofingwere installed with edges crimped together and solderedto form a weather‐tight surface. On steeper pitched roofs,long continuous seams were used, typically in a standingseam configuration, providing regular ridges down roofslopes. Corrugated or other paneled metal roofing wasalso common on commercial and industrial buildings aswell as outbuildings, such as sheds and garages.Remove metal roofing and install other materialDeterioration of the metal surface tends to occur fromwearing of the protective painted or galvanized surface,chemical action, rusting, pitting or streaking, airbornepollutants, rain or material acids, or galvanic action.Galvanic action occurs when dissimilar metals chemicallyreact against each other and corrode, and can come fromadjacent metals, such as fasteners and non‐adjacentmetals, such as roof cresting via rainwater.Architectural Review Committee.Install Rib Panel or R‐Panel at non‐commercialbuildingsCommission appeal.Commission appeal.HDLC Staff review.METAL ROOFING COLORMetal roof colors in New Orleans tend to be naturalmetal or natural copper, or if a painted finish is desired,colors that are similar to metal, such as silver to grey ormuted green. In the region, red metal roofs are morecommonly found in agricultural settings and aregenerally not appropriate within the City.The HDLC Staff provides final approval for metalroofing colors.City of New Orleans HDLC – Guidelines for Roofing 05‐5

REPAIR AND REMOVAL OF ASBESTOS SHINGLESGreat care should be taken when working with brokenasbestos products and during its removal. It isrecommended that all asbestos related work beundertaken by a licensed contractor.Property owners are responsible for ensuring that allasbestos removal and disposal is handled in accordancewith all applicable regulations and procedures.The asbestos shingle roof has terra cotta caps on the ridgeand hips and a triangular louvered vent at the front gable.The ridge caps and louvered vents should be retained.Gutter installation is recommended.ASBESTOSAsbestos became a popular roofing material at thebeginning of the 20th century. Asbestos roofing is madefrom asbestos mineral fibers and either Portland orhydraulic cement and it provides a durable, lightweight,economical, fireproof, rot and termite resistant alternativeto slate, terra cotta and corrugated metal roofing.With appropriate maintenance an asbestos shingle roofcan be expected to last well over 30 years, with crackingand rusting nails being the most typical cause of failure.Although the manufacturing of asbestos roofingessentially ceased when asbestos was banned by the EPAin 1973, the HDLC encourages the retention of existingasbestos roofing that continues to provide a watertightroof surface. If the roofing is damaged, consultation witha professional to determine whether repair is feasible isrecommended. It should also be noted that asbestosroofing is often available at architectural salvage suppliers.Typical localized problems and possible repairs forasbestos shingles:The asbestos roof has some non‐asbestos replacementshingles of a similar size and shape as the existing roofing.Asbestos Roof ReviewReplace asbestos roof with visually similar orinstall slate, imitation slate or metal materialHDLC Staff review.Replace asbestos roof with “architectural” or“dimensional” asphalt shinglesCommission appeal.HDLC Staff review.Remove asbestos roof and install other material Split or puncture – Install sheet metal under shingle, fillsplit or hole with grout of Portland cement and waterCommission appeal. Loosening or corrosion of fasteners for asbestos shingleor accessories – Reattach or replace fastenerHDLC Staff review. Moss or fungi on surface – Trim back adjacent treesallowing sun to dry out roof surface Missing or damaged shingles or roof accessories –Replace shingles with non‐asbestos shingles to matchoriginal and roof accessories in‐kindIf over 20% of the asbestos shingles on a roof slope aredamaged or missing, replacement of the roofing might bewarranted. Property owners are encouraged to considerinstalling salvaged asbestos roofing or non‐asbestos fiber‐cement products that visually duplicate traditionalasbestos tiles. Other alternative roofing materials arehard roofs, such as slate, terra cotta, metal or simulatedslate or terra cotta.05‐6 City of New Orleans HDLC – Guidelines for RoofingASPHALT SHINGLE AND SIMULATED SLATEROOFING COLORThe colors for asphalt shingle and simulated slate roofsin New Orleans should simulate the appearance ofslate. This typically will include a range of grays.Brown shingles, which simulate wood, are notappropriate in New Orleans. Applicants are notencouraged to install decorative color patterns orshaped shingles in replacement roof installations.HDLC Staff provides final approval for asphalt shingleand simulated slate roofing colors.

FLAT ROOFING SYSTEMSAlthough very few roofs are truly “flat”, low‐sloped,generally defined as a pitch below 3:12 slope, (3” rise for12” run), require a watertight roofing system. There are avariety of flat or low‐slope roof systems including: metalroofing; built‐up roofing, single‐ply roofing, and modifiedbitumen roofing.This dimensional asphalt shingle hipped roof features ridgetiles at the hips and a perimeter gutter.By contrast steeper pitched roof systems generally employshingles; in materials such as slate, terra cotta and asphalt;to shed storm water.ASPHALTTypical localized problems for flat roofs include:Asphalt became a popular roofing material at thebeginning of the 20th century providing a relativelyinexpensive and easily installed roofing material. Earlyroofing was generally made of asphalt‐saturated felts in avariety of shapes, styles, textures and colors. Today,asphalt shingles are made with fiberglass, generally as 3‐tab, “architectural” or “dimensional” shingles, whichinclude multiple layers of material with simulated shadowssuggesting wood or slate. Splits, punctures, or cracking of surface Standing water or poor drainageAn asphalt shingle roof can be expected to last from 15 to25 years with “architectural” or “dimensional” shingleslasting longer due to their multiple layers. Over time,asphalt shingles can curl, lose their mineral coating, bedislodged by wind or become brittle.Typical localized problems and possible repairs for asphalt: Split or puncture – Install sheet metal under shingle, fillsplit or hole with roofing cement Moss or fungi on surface – Trim back adjacent treesallowing sun to dry out roof surface Missing or damaged shingles or roof accessories –Replace to match originalIn selecting the most appropriate roofing material it isimportant to verify that the design addresses thebuilding’s drainage and specific details of the existingconditions including attachment, substrate and weightlimitations.Other factors include maintenancerequirements, anticipated life span in New Orleans’climate and hurricane resistance.Flat or Low‐Sloped Roof ReviewInstall new flat or low‐sloped roof visible from apublic right of wayHDLC Staff review.If over 20% of the asphalt shingles on a roof slope aredamaged or missing, replacement of the roofing might bewarranted.Asphalt Roof ReviewReplace existing asphalt roof in kindHDLC Staff review.Replace existing 3‐tab asphalt roof with new“dimensional” or “architectural” asphalt shinglesto simulate slateHDLC Staff review.Remove “dimensional” or “architectural” asphaltshingles and install 3‐tab asphalt roofingCommission appeal.HDLC Staff review.A flat or low‐sloped roof is located behind the parapet andbracketed cornice.City of New Orleans HDLC – Guidelines for Roofing 05‐7

Ridge caps are located along the roof hips, cresting is along the top ridge and a finial is found at the end of the main roofgable. Chimney placement reflects the internal organization of the residence and Chinese caps provide roof ventilation.ROOF FEATURESRoof features are decorative and sometimes functionalelements that help define the profile of a roof against theskyline and should complement the building’s style.Historic rooftop features include ridge caps, cresting,finials, roof vents, flashing, gutters, downspouts,chimneys, dormers, bell towers, turrets and monitors.More recent additions include skylights, mechanical andtelevision equipment and solar panels.Ridge tiles, cresting and finials can be found on avariety of building types and styles in New Orleans, andmore specifically on sloped slate, terra cotta, asbestos andasphalt roofs. They are visually important features,accentuating the changes in roof slopes, and the HDLCencourages their retention. Most prevalent are thosemade from terra cotta, in either overlapping barrel formsor in an English‐V mortared between joints. In addition,ceramic and cast iron versions are also still extant. Ridgecaps are typically located along a top ridge or hip of a roof,and cover the intersection where two roof slopes meet.Cresting is similarly located to ridge caps, but its locationtends to be limited to the upper portions of a roof. Finialsare often found at the end of a gable roof form or dormer.English V – Withmortar jointsSpanish Tiles – Withoverlapping jointsRidge Tile, Cresting and Finial ReviewInstall ridge tiles, cresting or finialsHDLC Staff review.Remove ridge tiles, cresting or finialsCommission appeal.HDLC Staff review.05‐8 City of New Orleans HDLC – Guidelines for RoofingRidge tiles in New Orleans are often in an English‐V profilewith mortar between adjoining tiles as seen in the topdrawing or in overlapping Spanish tiles as seen below.

Roof ventilation systems are generally located along oron the roof ridge and can greatly reduce the heat in anattic and home in the summer months.Chinese CapMost appropriate for allbuildings in Historic DistrictsTurbine VentilatorNot appropriate – Can onlybe installed as a replacementin‐kindPower Roof VentApproved only in less visiblelocationsRidge VentApproved only where ridgetiles are not presentRestaurant ventilation systems typically provideexhaust for cooking equipment. The installation ofrestaurant ventilation systems is subject to building coderequirements as well as HDLC review. Restaurant ventsand exhausts should be installed in a location where theyare not visible from the public right of way and withinthe building envelope.Roof Ventilation Systems ReviewInstall Chinese caps, replacement in‐kind ofturbine ventilators, power roof vents, ridge ventsHDLC Staff review.Restaurant vents and exhausts should be installed withinthe building envelope and in a location where they are notvisible from the street.Roof mounted equipment including mechanicalequipment, vents, television dishes and antennaeand mobile telecommunication equipment are allexamples of modern mechanical equipment and roofpenetrations that can affect the historic integrity of abuilding. Although it is understood that some roofpenetrations are required for items such as plumbingvents, property owners are encouraged to limit theamount of rooftop equipment and penetrations, andminimize the overall appearance of clutter.Property owners of sloped roof buildings are encouragedto locate rooftop equipment and penetrations a minimumof 10’‐0” back from the front building wall, and 12” belowthe roof ridge where they are visually minimized.The installation of rooftop mechanical equipment,such as air conditioner compressor units, mobiletelecommunications equipment or similar equipment, isnot permitted where they are highly visible from thepublic right of way.Install turbine ventilators, highly visible powerroof vents or ridge vents in place of ridge tilesCommission review.Install restaurant ventilation systems that arevisible from the streetCommission review.HDLC Staff review.Rooftop mechanical equipment should not be visible fromthe street.City of New Orleans HDLC – Guidelines for Roofing 05‐9

Roof monitors are structures that project up from theroof, used for ventilation with louvers, or for light orlookouts with windows. Monitors are often found onwarehouse buildings. Property owners are encouraged toretain historic roof monitors.Satellite dishes should be installed towards the rear of thebuilding so they are minimally visible from the street.Solar collectors provide a renewable energy source. TheCity of New Orleans encourages solar collectors for spaceheating, hot water and electricity. However in HistoricDistricts, property owners are encouraged to locate solarcollectors where they are minimally visible or hidden frompublic view. Solar collectors shall be located a minimumof 10’‐0” back from the front building wall, and 12”below the roof ridge. On Significant buildings and cornerproperties, it might be more appropriate to locate solarcollectors on the ground in the rear yard.Some skylights were historically located in warehouse andcommercial buildings, providing natural interior light andventilation. The visibility of new skylights should beminimized.Skylights are sometimes historically found in commercialbuildings. They are occasionally appropriate in sloped roofbuilding types and townhouses where dormer windowsare not present. Property owners are encouraged toselect skylights that do not extend more than 8” abovethe roof surface; minimize the overall number; locateskylights a minimum of 10’‐0” back from the frontbuilding wall, and 12” below the roof ridge, inunobtrusive locations, arranged in an orderly fashion.The installation should minimize alteration of the roofstructure with the long dimension oriented down the roofslope.PREFERRED LOCATIONS FOR ROOF OBJECTS The HDLC encourages the placement of all roofmounted equipment including mechanical equipment;vents; television dishes and antennae; solar collectorsand skylights in a manner that is as visually unobtrusiveas possible from the street, as represented by thedarker shaded areas in the above drawing. Placement is encouraged facing a rear yard whereverpossible. If it is not possible, placement is preferredas far back on a side slope as possible. Anyinstallation must be a minimum of 10’‐0” from thefront building wall and a minimum of 12” below aroof ridge and above the roof eave. Applicants are encouraged to install skylights andsolar collectors that do not extend more than 8inches above the roof surface. Skylights are notapproved on roof slopes with dormers.Roof Mounted Equipment, Solar Collectorand Skylight ReviewInstall unobtrusive roof mounted equipment,solar collector or skylight – Minimum 10’‐0” fromfront building wall, less than 8” above roof surface:Commission review.HDLC Staff review.Install new visually prominent roof mountedequipment, solar collector or skylightCommission appeal.Roof monitors are more typically found on commercialbuildings and often provide interior light and ventilation.05‐10 City of New Orleans HDLC – Guidelines for RoofingHDLC Staff review.

ChimneysAn inverted “V” cap isat the top of thechimney and flashingat its base.These gable roof dormers are appropriately located,proportioned and detailed for the building and includeslate cheek walls. Spanish tile ridge caps should beretained.Dormers, also known as dormer windows, protrude fromthe roof surface with a window providing light andadditional headroom under roof eaves. Dormers can havevarious roof shapes but are typically gables. Propertyowners are encouraged to retain existing historic dormersand reconstruct dormers on buildings where there is clearevidence that they existed. Evidence can be historicphotographs indicating a dormer or visible within atticroof framing.weretypicallydesigned to complement thestyle of a building and period ofconstruction. In New Orleans,most are constructed of brick,some of which have beencovered by stucco or plaster, andthey are most often locatedwithin the building walls ratherthan be attached to an exteriorwall. The rhythm and placementof chimneys typically reflect theinternal organization of abuilding and represent animportant building feature.Most building types and styles, including shotguns andcolonial revival buildings, tend towards square orrectangular chimney shafts, sometimes with molded tops,are often covered with inverted “V” shaped caps.Victorian period chimneys can include decorative detailingincluding corbelling, varied patterns, undulating andmolded surfaces and decorative terra‐cotta chimney pots.Removal of historic chimneys is only approved by theHDLC if they are structurally deficient. The visibility ofnew chimney flues should be minimized, and new fluescan generally be clad in brick or stucco.When considering a new dormer, particularly at historicbuildings, property owners are encouraged to considercomparable buildings of the same style and periodincluding the location, form, spacing, dimensions,proportions, style and detailing. For example, dormers arenot typically appropriate on side elevation roof slopes.Cheek wall cladding materials vary with building materials.On masonry buildings, dormer cheek walls should beslate unless the roof is metal, in which case they can bemetal. On wood frame buildings, dormer cheek walls canbe slate, wood or cementitious clapboard siding.Dormer ReviewReconstruct previously existing dormer – Mustprovide evidence of previous dormer, scaled elevations,sections and detail drawingsThis row of three chimneys suggests the division of roomson the interior of the building. The central chimneyincludes an inverted “V” cap and English V ridge tiles withmortared joints marking the top of the roof.Chimney ReviewRemove structurally deficient chimney orinstallation of visually unobtrusive chimne

introduced, including metal roofing, asbestos and asphalt based shingles, as well as varieties of rolled or built‐up roofing for flat installations. As time progressed, the variety of metal roofing was also expanded to include copper, galvanized sheet steel and aluminum.