The government's decision to require second staircases in residential buildings over 18m has major design implications. We examine the policy and alternatives.. The Second Staircase Policy Current Position Residential buildings over 18m will require two staircases Transitional arrangements for buildings already in design/planning Significant impact on floor plate design and construction costs Why Two Staircases? Provides alternative escape if one stairway is compromised by fire or smoke Allows firefighting operations on one stairway while residents evacuate via another Aligns UK with international practice (most countries already require dual stairs) Design Impact 5 8% loss of net lettable area Core design significantly affected Corridor and lobby layouts must be redesigned Cost increase estimated at 5 10% for residential towers Single Staircase Alternatives For buildings 18 30m, alternatives may still be possible: Firefighting lobby approach Enhanced sprinkler protection Smoke control system improvements Evacuation alert systems For tall building fire engineering, contact us.