Gable
Two principal planes meet at a ridge. Cross-gables create additional valleys and intersections.
HOME KNOWLEDGE LIBRARY · UNDERSTANDING THE HOME
Roofing Systems
Discover how residential roofs protect homes, carry structural loads, control moisture and heat, and shape architectural character. Explore roofing materials, construction layers, historic rooflines and documented Greater St. Louis examples.
Explore Roofing Systems
Select a photographic family to discover its complete research directory. All eight choices remain visible.
Anatomy of a Residential Roof
Explore the relationship between the visible roof covering and the supporting, weather-control and thermal-control layers.
Conceptual pitched roof · Not to scale
Roof assemblies vary; this diagram is not a construction specification.
Roof Shapes & Configurations
Roof geometry affects drainage, interior volume, material suitability and architectural identity.
Hip
Roof planes slope toward multiple sides, meeting at hips and ridges.
Mansard
A steep lower roof slope and shallower upper portion create a distinctive historic profile.
Gambrel
Two slopes on each of two sides form a characteristic barn-like roofline.
Shed
A single sloping plane may cover an entire structure or an addition.
Low-Slope
Requires compatible water-control membranes and intentional drainage design.
Butterfly
Inward-sloping planes create a central valley requiring carefully designed drainage.
Roof Pitch
A 6:12 pitch rises six units vertically over twelve horizontal units; slope limits differ by covering.
Roofing Materials & Coverings
Materials differ in weight, attachment, weathering, repairability and compatible roof pitch. No single material is best for every roof.
Natural slate is one example of a durable roof covering requiring material-specific installation and repair.
Tile roofing is another distinct system, with structural and fastening requirements that vary by product.
Asphalt shingles
Overlapping manufactured shingles; installation details and underlayment requirements vary with slope and exposure.
Natural and synthetic slate
Different products that may look similar but have different composition, fasteners and weathering characteristics.
Clay and concrete tile
Profile, mass, fastening and underlayment must be considered as a complete system.
Wood shingles and shakes
Material moisture, fire classification and local requirements deserve attention.
Standing-seam metal
Seams, clips, thermal movement and roof geometry influence performance.
Metal shingles and panels
Not identical to standing seam; attachment and water-shedding details differ.
Built-up and modified bitumen
Layered systems commonly associated with low-slope applications.
Single-ply membranes
Seams, penetrations, drainage and substrate compatibility are essential.
Roof Framing & Structural Support
The structural roof transfers gravity, wind and other applicable loads to walls, beams and ultimately foundations.
Exposed framing helps distinguish supporting members from roof coverings.
Rafters
Individual sloping members generally span between a ridge or other support and exterior bearing points.
Engineered trusses
Manufactured assemblies depend on designed webs, chords, bracing and connections.
Ridge board vs beam
A ridge board is not automatically a structural ridge beam; the distinction changes the load path.
Wind uplift
Connections must transfer uplift and lateral forces as well as downward gravity loads.
Cutting, drilling or removing roof framing can change structural behavior. Professional review may be needed before alterations.
Decking, Underlayment & Weather Barriers
The layers beneath a visible covering are crucial to support, water control and assembly compatibility.
Partially completed roofing can reveal battens, roof openings and the layers beneath the covering.
Decking
Historic planks, plywood and OSB provide substrates with different attachment and condition considerations.
Underlayment
Felt and synthetic materials provide secondary water-shedding protection in many pitched assemblies.
Ice barriers
Self-adhered membranes can provide localized protection where required or specified.
Assembly compatibility
Slope, covering, fasteners, deck condition and manufacturer instructions must work together.
Flashing, Drainage & Water Management
Roof water management is a continuous path: across the covering, through valleys and edges, and away from walls and foundations.
Step and counterflashing
Roof-to-wall and chimney intersections need coordinated overlapping metal or compatible flashing details.
Valleys and penetrations
Intersecting planes, vents and skylights concentrate water and demand appropriate transitions.
Gutters and downspouts
Collecting and discharging runoff helps protect wall assemblies and adjacent ground.
Low-slope drainage
Drains, scuppers, overflow paths and designed slope help avoid prolonged ponding.
Roof surfaces → collection → discharge
Conceptual flow only; actual roof valleys, drainage paths and flashing configurations vary.
Ventilation, Insulation & Energy Performance
Roof and attic assemblies manage heat, air leakage and moisture. Vented and properly designed unvented assemblies are distinct strategies.
Vented attic
Intake and exhaust ventilation can help manage attic conditions when designed and installed appropriately.
Unvented attic
Insulation and condensation-control strategy are coordinated at the roofline or other specified locations.
Air sealing and insulation
Uncontrolled interior air leakage can transport moisture; thermal and air barriers work together.
Reflective and cool roofs
Solar reflectance can influence surface temperature, but overall performance depends on climate and the full assembly.
Do not assume every attic should be vented or that ventilation alone resolves condensation. Refer to applicable code, design and climate requirements.
Roof Conditions, Maintenance & Repairs
Learn to document visible conditions without assuming their cause or recommending replacement from a photograph alone.
Illustrative roof-covering deterioration. Cause and repair scope require inspection.
Missing or displaced covering
May relate to wind, fastening, deterioration or installation.
Interior staining
Can indicate water exposure but does not identify the precise roof entry point.
Sagging or deflection
May warrant evaluation of structural members and load paths.
Leak and flashing assessment
Localized failures may be repairable; broader failures may require more extensive work.
Avoid walking on roofs or climbing ladders to diagnose conditions. Significant structural movement, falling materials or active electrical hazards warrant prompt professional attention.
Roofing Through Time
Explore broad historical developments. These periods overlap; they do not establish the original material or age of a particular roof.
Roofing in Greater St. Louis
Our region offers opportunities to compare nineteenth-century urban rooflines, early suburban homes and postwar construction.
Historic Lafayette Square architecture offers documented examples of Victorian roof forms and dormers.
Lafayette Square
Second Empire mansard rooflines and dormers are prominent features in documented historic-district architecture.
Historic masonry neighborhoods
Parapets, chimney intersections and concealed roof drainage deserve building-specific research.
Early suburbs
Craftsman and Tudor Revival rooflines offer contrasting pitches, gables and overhangs.
Metro East Illinois
Historic Alton and Belleville records can support individual roof-form case studies; materials must be verified.
Explore the City of St. Louis Preservation Plan and Illinois HARGIS for documented architectural context.
Sources of Truth
Research standards, technical guidance, archival collections and Greater St. Louis documentation. Expand only the categories relevant to your interests.
Codes & Roofing Standards · 4 research resources
International Code Council
The International Residential Code organizes roof-ceiling construction and roof assemblies into distinct chapters. Consult the locally adopted edition and amendments for applicable requirements.
Explore research resourceFEMA Building Science
FEMA publishes technical resources on wind resistance, resilient construction, roof-to-wall connections and post-disaster performance. These materials explain forces and failure mechanisms.
Explore research resourceASTM International
ASTM publishes material and test standards used in roofing product evaluation. Individual standards may require purchase or subscription; availability and applicability vary.
Explore research resourceUL Solutions
UL provides product testing and certification information relevant to roof-covering fire and other performance classifications. Product listings should be interpreted in their tested assembly context.
Explore research resourceProfessional Roofing Research · 4 research resources
National Roofing Contractors Association
NRCA publishes roofing technical guidance and professional educational resources. Its material helps explain roof-system components, installation considerations and maintenance.
Explore research resourceAsphalt Roofing Manufacturers Association
ARMA provides asphalt-roofing technical publications and guidance on asphalt shingle systems, ventilation and maintenance. Product-specific instructions still control installation.
Explore research resourceMetal Construction Association
The association offers information on metal roofing systems, material performance, coatings, fastening and design considerations. Different metal systems should not be treated as interchangeable.
Explore research resourceRoofing Industry Committee on Weather Issues
RICOWI coordinates research and reporting related to roofing performance under weather events. Its resources support evidence-based discussion of wind and hail effects.
Explore research resourceBuilding Science & Energy · 4 research resources
DOE Building America Solution Center
Building America publishes illustrated guides on flashing, attic assemblies, air sealing, insulation and moisture control. These are especially valuable for explaining hidden roof layers.
Explore research resourceOak Ridge National Laboratory
ORNL conducts building-envelope and energy research, including roofing and thermal performance. Research findings require attention to climate and test conditions.
Explore research resourceU.S. Department of Energy
DOE consumer and technical resources explain home energy performance, insulation and roofing-related heat transfer. They complement rather than replace building-specific design.
Explore research resourceENERGY STAR
ENERGY STAR provides information about energy efficiency and certified products. Certification criteria and product categories change; verify current program requirements.
Explore research resourceHistoric Roofing & Preservation · 4 research resources
NPS Preservation Briefs
National Park Service Preservation Briefs discuss historic roofing materials, repair principles, preservation compatibility and moisture management. They are valuable for older residences.
Explore research resourceNPS Heritage Documentation
HABS/HAER/HALS documentation includes measured drawings, photographs and building histories. These records can reveal historic roof configurations and construction details.
Explore research resourceLibrary of Congress Historic Buildings
The Library of Congress provides access to historic-building survey records, including archival roof and framing documentation. Check each record for rights and access information.
Explore research resourceNational Register of Historic Places
Nomination forms and related documentation may identify historic architectural forms and character-defining roof features for individual properties or districts.
Explore research resourceMissouri & Illinois Preservation · 4 research resources
Missouri State Historic Preservation Office
Missouri preservation records, surveys and district nominations can provide context for roof forms and historic building materials. Records vary in detail and coverage.
Explore research resourceIllinois HARGIS
Illinois historic-property mapping and survey information can help identify documented structures and districts. Inventory coverage is not comprehensive.
Explore research resourceIllinois Historic Preservation
State preservation resources provide research pathways for historic Illinois architecture and exterior alterations. Local regulations may impose additional requirements.
Explore research resourceMissouri Digital Heritage
Digitized maps, photographs and historic records can help place residential roofing changes within broader Missouri development history.
Explore research resourceGreater St. Louis Architectural Research · 4 research resources
City of St. Louis Cultural Resources
Local historic district records and preservation guidance document architectural characteristics and review standards for some St. Louis neighborhoods.
Explore research resourceSt. Louis Preservation Plan
The preservation plan organizes the city’s architectural history and provides examples of rooflines, historic forms and neighborhood development.
Explore research resourceLandmarks Association of St. Louis
Local preservation research and architectural archives support investigation of historic St. Louis buildings and original exterior features.
Explore research resourceState Historical Society of Missouri
Architectural drawings, firm records and historical collections can support research into original roof design and subsequent changes.
Explore research resourcePhoto Credits & Licenses
Photographic examples are sourced from Wikimedia Commons file records. Please confirm the individual file-page license and attribution before commercial publication; this initial build does not represent completion of image-rights clearance.
Technical diagrams on this page are conceptual educational graphics, not engineered construction details. Sources may update their pages or links.