Dating a building Flashcards
Important dates and facts
• Pre-1940’s was mostly wood or unreinforced masonry
• Post-1940’s saw the introduction of reinforced masonry
• ~1950 saw cinderblock construction becoming popular
• Trusses are not new! However, the gusset plates changed the framework and methods of attachment
• 1980 saw the rise of Orientated Strand Board (OSB) and Truss Joist I-beam (TJI)
o About 5 min of flame will cause failure conditions
Commercial trusses
o Wide span and wide spacing
o Decreased interior partition
o High ceilings
o Exposed structural members
Residential trusses
o Wide spans
o Trusses 24in on center
o Increased interior partitions
o Complex roof structures
Container fires
o Conditions inside the box
o Smoke, heat, hazards
Structure fires
o Conventional framing Simple roof construction Dimensional lumber sheeting Ridge beams Simple duct work o Truss construction Fire conditions (10min rule) Complex roof structures OSB Tile roofs Flex ducts
30’s conventional framing
o Generally stronger o Collar ties o King/queen posts o Bearing wall o Ridge beams o Generally 2x4 long span
30’s arch lintel
o Indication of un-reinforced masonry
o Line mortar
o Single hung windows
30’s skip sheeting
o Skip with wood shingles or tile
o Numerous layers of roofing
o Skip filled in or covered with plywood additional dead load
30’s high pitched roof
o Large attic spaces
o 8 — 12 foot not uncommon
o Attic spaces converted to living areas
o Hidden stairways
30’s raised floors
o Falling through wood
o Floors become a concern
30’s root cellers and half basements
o Falling through wood floors
o Especially a concern if sealed up and forgotten
30’s cloth wiring on insulators
o Utilities now a concern
30’s wood lath and plaster
expanded wire/ wire lath tin ceilings the ’50s’ style building
o Extreme manpower needed to open up concealed spaces
30’s high ceilings
o 6ft pike pole may not reach
30’s dormer vents
o Along with skip sheeting, converting an attic fire may be difficult
30’s age of building
o 80-100 year old buildings can be extremely dilapidated.
30’s balloon framing
o Not really seen in Tucson, but could be a possibility in older 2 story buildings
o Possibility of pancaking
30’s box beam/columns
o Lightweights supporting members
o Concealed spaces
50’s block construction/red brick construction
o Stronger walls
o Lime mortar usually no longer an issue
o Steel lintels
o No grout cells
50’s steel case windows
o Escape may be difficult
50’s conventional framing
o Generally 2x6 construction o Collar ties o Ridge beams and poles o Bearing walls o 1x6, 1 x10, sheathing
50’s plasterboard
o Difficult access to ceiling and concealed spaces
o Introduction of foam to attics had the potential of dropping areas of ceiling because of absorption by 3/8” plaster board
50’s wiring
o Can be brittle insulation generally not grounded
o Can become and entanglement hazard in attics
o On a short circuit can conduct electricity and transmit heat - overhaul issue
60’s frame or block walls
o Pre 1978
o No grout cells
60’s lightweight construction
o Prefabricated trusses
o Gusset plates
o 2x4 construction
o No ridge beams
60’s plywood
o Replaces 1x6, 1x10 sheeting
60’s half inch drywall
o Easy breaching
60’s numerous additions
o Concealing spaces
o Questionable construction
60’s Aluminum case windows
o Easy breaching
o Self-ventilating
Present lightweight construction
o Elapsed time becoming critical
Present OSB/TJI
o Engineering products replacing solid wood
Present architectural diversity
o Concealed spaces, build-overs increasing
Present flex duct
o Extreme entanglement hazard
Present up dux
o Retrofit- attic involvement almost immediate
Present engineered wood
o 2x4 can be the biggest piece of solid wood in the construction site
Present alternative building materials
o Unconventional wall/roof/floor systems
Present lightweight truss headers
o Lightweight trusses are replacing previously solid lumber
