Roof Deck on Historic Capitol Hill Penthouse

Project Overview

This 307-square-foot rooftop deck addition transformed an 1895 historicrowhouse on Capitol Hill in Washington, D.C. into an outdoor entertaining spacewith views of the Washington Monument and the U.S. Capitol Building. Thisproject earned a Grand Award from NARI Metro DC in the Outdoor Living over$60,000 category. Landis worked with the homeowners from initial design throughhistoric district approval and construction to turn an inaccessible attic androof hatch into a fully livable outdoor room.

Design Challenges

Before the renovation, the only way to reach the roof was by climbing a ladderfrom the second floor into a three-foot-high attic space, then using a secondladder to get through the roof hatch. The clients wanted a deck they couldactually use to relax and host guests, with a real staircase and a properdoor.

Because the home sits in a designated historic district, no new portion of therooftop structure could be visible from the street. On top of that, the roofdeck was legally treated as a "penthouse" addition, which triggeredsetback requirements. Delivering a code-compliant, functional, contemporaryspace within those constraints, on a 122-year-old rowhouse, took carefulengineering and design.

Methodology

Landis' design team worked with the DC Historic Preservation Review Board fromthe outset. To prove the new roof access structure wouldn't be visible from thestreet, the team built a full-scale wood mock-up on the roof and physicallychecked sightlines from the street before finalizing the design. The team usedRevit 3D modeling to check four critical height points, confirming the stairswould clear code minimums while keeping the structure hidden from streetview.

The access structure and deck walls are clad in light blue Hardie panels, and thedeck surface is Trex Select composite. Inside, the new stairs feature a stainless-steelcable rail system that lets light pass through the stairwell, and the existingfirst-to-second-floor stairs were rebuilt to match, so the whole stair runreads as one continuous, contemporary design.

FAQ

How much does a rooftop deck cost in Washington, D.C.?
LandisArchitects and Builders - Pricing and Financing‍

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Can you build a roof deck on a historic rowhouse in Capitol Hill?
Yes, but any new structure must be approved by the DC Historic PreservationReview Board and generally cannot be visible from the street.

Why do rooftop decks on DC rowhouses needa setback from the front of the building?
DC building code treats rooftop structures like this one as a"penthouse" addition, which requires a horizontal setback equal tothe height of the penthouse structure.