Every answer and its explanation appears here once you have finished the path. Each one then links to the matching glossary entry, where the concept is set out in full with its worked example.
1. Under an all-risks construction policy, what must the insured establish, and what does it not have to establish?
The damage, that it arose within the period, and that it was fortuitous; it does not have to prove the cause
That is the inversion peculiar to all-risks cover, and it governs how a file is run before the first expert visit: cover extends to everything not excluded, so establishing the cause is the work of whoever wants to invoke an exclusion, not of whoever claims. The answer putting the cause on the insured is the one produced spontaneously by the habit of named-perils policies, and it costs months spent proving something the insured never had to. Demanding in addition the absence of fault by a site party confuses a property policy with a liability action.
Glossary entry →2. The insurer invokes defective design. How many things must it establish, and which is the most neglected?
Two, the defect and its causal role, and the second limb is the most neglected and often the hardest
A defect can exist and have played no part in the loss, and that second limb is the one expert reports handle fastest, often in a single sentence, because it seems to follow from the first. It does not: that is where files thought lost on the reading of an exclusion are won. Looking for the author's fault, as another answer suggests, imports liability reasoning into a property policy, where the exclusion targets a state of the thing and not a behavior.
Glossary entry →3. Predictable wear, an anticipated settlement, certain damage. By which route do they fall outside cover, and why is it the shortest?
Through the absence of fortuity: no exclusion has to be proved, cover presupposing an uncertain event
Fortuity is a condition of cover and not an exclusion, so the insurer has nothing to show beyond the certainty of the damage: it never enters the argument about the defect, its causal role or the drafting of the exclusion. It is the shortest door, and you need to know it exists so as not to build a whole file on ground the insurer will not take. Two of the other answers name real mechanisms operating later, one on proof, the other on the amount, and never on whether cover exists.
Glossary entry →4. On a site, evidence is destroyed for good reasons: clearing, securing, resuming work. What effect does that destruction have?
An asymmetrical effect: the insured wins the principle, the insurer being unable to establish an exclusionary cause, and loses the amount, being unable to quantify
The asymmetry follows directly from how the burden is allocated: the insurer loses its exclusionary cause along with the evidence, while the insured, which must quantify, loses its amount with the same evidence. The practical consequence is that an insured victorious on principle can walk away with far less than it expected, and it is settled in the two days after the loss, while the site is being cleared. The answer believing it symmetrical is comfortable and wrong; the one making it unfavorable to the insured alone forgets that an exclusion must be proved, and by the other party.
Glossary entry →5. On what is a file lost more often than on causation, and which confusion is responsible?
On the preservation clause, confused with emergency measures: holding a contractual milestone is not an urgent protective measure
The clause requires the site to be left as found until inspection, save for urgent protective measures, and it is that exception the site widens without thinking: resuming work to hold a date already means producing, and no longer preserving. The confusion is all the easier because both actions look alike on the ground and are decided by the same people in the same hours. The other three answers name real and well-known confusions, which is exactly why they get handled: this one goes unnoticed because nobody sees themselves destroying evidence by keeping to schedule.
Glossary entry →