How Is Mausoleum Drainage Design Engineered to Protect Crypts?

The roof drainage layout is drawn for the storm the code requires, not the average rain. The engineer computes the roof's tributary areas, sizes primary interior drains or gutters for the design rainfall intensity, and — critically — designs the secondary overflow: scuppers through the parapet set slightly above the primary drain level, sized to handle the full storm if every primary drain clogs. That redundancy is what keeps a leaf-choked drain in October from becoming a collapsed roof in November. Detailing decides whether the system works for fifty years. The engineer specifies drain domes that resist clogging, details the membrane flashing at each drain as a waterproofing assembly, and requires tapered insulation or structural slope so no area ponds. Parapet coping is detailed with drips and sealant joints that the maintenance crew can inspect and renew. The drawings call out the overflow scupper elevations explicitly, because a scupper set too high is no overflow at all.

Below-grade waterproofing is specified as a system: membrane selected for the hydrostatic conditions, protection board against backfill damage, drainage composite to carry water down to a perimeter drain, and that drain daylighted or pumped to a positive outfall. The engineer sizes the perimeter drain, details its cleanouts, and — where the water table or soils demand it — adds an interior backup drain or sump with alarm. Dampproofing alone is never accepted where crypts sit below grade. Above grade, the facing stone gets a drainage plane: an air space or drainage mat behind the veneer, flashing at every shelf angle, and weep holes at the base that actually weep. The engineer assumes the veneer leaks and designs the backup wall to stay dry regardless. Around the building, finish grades fall away at a minimum of 5 percent for the first several feet, walks and plazas pitch to drains, and the irrigation design keeps spray off the walls — because the best waterproofing still prefers not to be tested daily by sprinklers.

Use this checklist before the permit set is finalized: • Roof drains sized for the design storm; overflow scuppers set and sized as true secondary drainage • Roof sloped so every point drains; no ponding areas on the drainage plan • Below-grade walls given full waterproofing systems with drainage composite and perimeter drains • Above-grade veneer detailed with drainage planes, flashing, and weep holes • Every penetration, joint, and transition detailed — waterproofing fails at details • Site grades fall away from the building; hardscape pitched to area drains • Irrigation kept off walls and foundations • Perimeter drain cleanouts shown; sump with alarm where gravity outfall is not possible