Structural Load Assessment

1. Approach the structure and observe the overall geometry from a distance. Visible lean, sag, or asymmetry indicates structural compromise. Do not enter a structure with visible lean exceeding 2° from vertical.
2. Inspect the foundation. Look for cracking, settlement, erosion of supporting soil, or separation between the foundation and the structure above. Foundation failure is the most common mode of collapse in degraded structures.
3. Inspect the primary structural members (columns, beams, load-bearing walls). Look for material-specific degradation indicators listed below.
4. Inspect the roof structure from the exterior. Sagging ridgeline, missing or displaced roofing material, and visible daylight through the roof indicate advanced degradation. Roof collapse risk increases significantly where water infiltration has affected structural members.
5. If the exterior inspection does not reveal disqualifying conditions, enter cautiously. Apply load gradually. Test floor areas near load-bearing walls first, where the span is shortest and the load path to the foundation is most direct.

Timber

Probe with a pointed tool. Sound timber resists penetration; degraded timber allows the probe to enter with minimal force. Key indicators: soft or spongy surface, visible fungal growth, insect galleries (small holes in regular patterns), checking (deep longitudinal cracks), and discoloration indicating prolonged moisture exposure. Timber in ground contact degrades first. Timber protected from moisture by paint, oil, or roofing may be sound even after extended exposure. Load-bearing timber members that show probe penetration exceeding 10 mm should be considered compromised.

Concrete

Key indicators: surface spalling (flaking of the concrete surface, exposing aggregate or reinforcement), cracking patterns (map cracking indicates chemical degradation; linear cracking along reinforcement lines indicates rebar corrosion and expansion), exposed rebar (indicates loss of protective concrete cover; if rebar is visibly corroded, the member has lost reinforcing capacity), and efflorescence (white deposits on the surface, indicating water migration through the concrete). Concrete with exposed and corroded rebar has reduced load capacity. Concrete with map cracking over more than 30% of a structural member's surface should be considered compromised.

Steel

Key indicators: surface rust (cosmetic if shallow, structural if deep), section loss (visible thinning of the member), buckling or deformation, connection failure (bolts missing, welds cracked, plates separated), and paint or coating failure exposing bare metal. Measure section loss by comparing the current thickness to the original dimension where possible. Section loss exceeding 20% of the original member thickness indicates significant capacity reduction. Connections are the most critical inspection point—a sound member with a failed connection provides no structural value.

Masonry

Key indicators: mortar joint deterioration (missing, soft, or sandy mortar), cracking patterns (stair-step cracking along mortar joints indicates foundation settlement; vertical cracking through units indicates overload), leaning or bulging walls, and separation at corners or intersections. Masonry walls are strong in compression but weak in tension. A wall that is plumb and has intact mortar joints retains most of its compressive capacity. A wall with visible lean has reduced capacity that decreases rapidly with increasing lean angle. Do not load a masonry wall with lean exceeding 1° from vertical.