Stair Penthouse . Our brief was to create a feature staircase with a look of ultimate luxury using premium materials without visible fixings. One on the imperial fleet and one on the republic fleet, both look similar, but with unique and distinctive. Elegant Modern Penthouse With Glass Theme iDesignArch Interior from www.idesignarch.com In buildings four or more stories or more than 40 feet (12 192 mm) in height above grade, one stairway shall extend to the roof surface through a stairway bulkhead complying with section 1509.2, unless the roof has a slope steeper than 20 degrees (0.35 rad). The green roof condominium is brought to the market by: Our brief was to create a feature staircase with a look of ultimate luxury using premium materials without visible fixings.