Material catalogue

    Evidence atlas: what old-house materials show, and what they do not

    Eight material types that commonly turn up in Canadian houses built between 1900 and 1990, catalogued the way a record should be read: observation first, association second, confirmation by a professional or a document last.

    Can you identify a home's hazards from materials you can see?

    No. A visible material tells you what to ask about, not what is present. Cloth-covered wiring, grey supply pipe or a textured coating are era-associated observations. Whether a material contains asbestos or lead, whether a circuit is live, or whether a pipe is failing is established only by a licensed professional, a laboratory test, or a record.

    Overhead catalogue photograph of nine salvaged building materials arranged in a grid on a pale background: a plaster-and-lath panel, cloth-covered wiring on a porcelain knob, galvanized steel pipe and coupling, a cast iron drain bend, copper tubing, a weathered masonry unit, folded asphalt roofing, and a blank rusted equipment data plate.
    Educational illustration. Original photograph commissioned for OldHouses.ca showing representative salvaged materials. It is not a property identification tool, not evidence about any address, and not a substitute for laboratory analysis or a licensed professional's assessment.

    Catalogue entries

    1. Plate 01

      Wood lath and plaster

      What you might observe
      Narrow wood strips behind a broken plaster edge, or a wall that sounds solid and slightly irregular rather than hollow and flat.
      What it can be associated with
      Wall assemblies common in Canadian houses before drywall became the usual interior finish; often paired with older wiring and framing routes.
      What it cannot establish
      It cannot establish the build year, whether the wall cavity is insulated, or whether any coating on it contains lead or asbestos.
      Who or what can confirm it
      A qualified hazardous-materials assessor with laboratory analysis for coatings or textures; a renovation contractor or building-permit record for the assembly history.
      Lead paint: what an observation does and does not show

    2. Plate 02

      Cloth-covered conductor and porcelain support

      What you might observe
      Single conductors with a fabric-like outer covering passing through a ceramic knob or tube, usually visible in a basement joist bay or attic.
      What it can be associated with
      Early branch-circuit wiring methods used in Canadian houses in the earlier part of the 1900s.
      What it cannot establish
      It cannot establish whether the circuit is live, whether it was abandoned in place during a later rewire, or how an insurer will treat the property.
      Who or what can confirm it
      A licensed electrician's written assessment of what remains energized; electrical permit or inspection records from the provincial authority or municipality; the insurer's own written answer.
      Knob-and-tube wiring

    3. Plate 03

      Galvanized steel supply piping

      What you might observe
      Grey threaded pipe with a dull zinc-toned surface, typically at the water entry or in older basement runs.
      What it can be associated with
      Water supply piping used in many Canadian houses before copper and, later, plastic supply systems became common.
      What it cannot establish
      It cannot establish interior corrosion, remaining service life, water quality at the tap, or whether the rest of the system matches what is visible.
      Who or what can confirm it
      A licensed plumber's assessment, including hidden runs; municipal records for the service connection; a laboratory water test through your municipality or an accredited lab.
      Galvanized plumbing

    4. Plate 04

      Cast iron drain fitting

      What you might observe
      Heavy dark drain piping with thick walls and hubbed or banded joints.
      What it can be associated with
      Drain, waste and vent piping used widely in older Canadian housing stock.
      What it cannot establish
      It cannot establish the internal condition of the pipe, the presence of blockages or breaks below the floor, or the condition of the buried lateral.
      Who or what can confirm it
      A drain camera scope by a licensed plumber or drain contractor; municipal records for the sewer lateral where they exist.
      Cast iron plumbing

    5. Plate 05

      Copper supply tubing

      What you might observe
      Smooth reddish tubing with soldered joints, often mixed with older materials.
      What it can be associated with
      A later supply material; a copper section next to an older material usually indicates partial replacement rather than a whole-house system.
      What it cannot establish
      It cannot establish that the entire supply system was replaced, when the work was done, or that it was permitted.
      Who or what can confirm it
      A licensed plumber tracing the system, plus plumbing permit records held by the municipality or provincial authority.
      Systems: plumbing through time

    6. Plate 06

      Masonry unit with weathered face

      What you might observe
      Brick or block with eroded faces, spalling, repointed joints, or mortar that differs in colour and texture between areas.
      What it can be associated with
      Long service exposure and past repair campaigns. Mortar colour changes commonly mark repointing rather than original construction.
      What it cannot establish
      It cannot establish structural adequacy, the cause of movement, or whether a crack is active.
      Who or what can confirm it
      A masonry contractor for repair scope; a professional engineer where movement, bulging or structural questions are involved.
      Foundation cracks: what to record

    7. Plate 07

      Layered asphalt roofing sample

      What you might observe
      Granulated roofing material, sometimes in more than one layer at an edge or in the attic sheathing view.
      What it can be associated with
      Roof coverings replaced over the life of the house, occasionally installed over an earlier layer.
      What it cannot establish
      It cannot establish the remaining life of the roof, the date of the last replacement, or the condition of the deck and flashings.
      Who or what can confirm it
      A roofing contractor's written assessment; the building permit or invoice record for the last replacement; the seller's documentation.
      Systems: roofing through time

    8. Plate 08

      Equipment data plate

      What you might observe
      A metal or foil plate on a furnace, boiler, tank or panel carrying a model number, serial number and ratings — often corroded or painted over.
      What it can be associated with
      The single most useful record on site: a legible plate lets a professional look up equipment identity and often a manufacturing date range.
      What it cannot establish
      A plate does not establish installation date, service history, current safe operation, or that the appliance matches the rest of the system.
      Who or what can confirm it
      A licensed HVAC or gas technician for the appliance; the manufacturer for serial decoding; permit records for the installation date.
      Old furnace inspection

    Evidence note

    Sources
    Jurisdiction
    Canada; provincial licensing and permit rules differ by jurisdiction
    Applies to
    Buyers, owners and sellers of Canadian homes built roughly 1900–1990
    Last reviewed
    2026-09 (source links checked 2026-09-01)
    Limitations
    Material appearance varies widely. Nothing here identifies a material in a specific home or characterises its condition.
    What you should verify
    Laboratory analysis for suspect materials and a licensed professional's written assessment for each system.