How much force does a deck guardrail or handrail have to resist?

Guards and handrails must resist a single 200-pound concentrated load applied in any direction at the top (IRC Table R301.5).

Table R301.5 requires guards and handrails to withstand a single concentrated load of 200 pounds applied in any direction at any point along the top rail.

Guard in-fill components — the balusters or panels between rails — are separately required to resist a 50-pound load applied horizontally over a one-square-foot area, and that load is not assumed to act at the same time as the 200-pound top-rail load.

These loads are what drive post spacing and connection detailing, which is why ledger, post, and rail attachments matter as much as the railing height itself.