Through-wall roof scuppers are used in two circumstances. The first is for roof drainage where a gutter is ruled out for whatever reasons. The second is a backup system in case roof drains clog to prevent roof water from accumulating excessively and collapsing the roof structure. 
In each case the scupper extends through a parapet to allow roof water to drain either into a conductor head and downspout or simply down the face of the building in the case of overflow scuppers.
Some codes require a secondary roof drain system as backup to the main roof drains. Scuppers may eliminate the need for secondary overflow roof drains. In extremely large roofs, scuppers may not be feasible.
The traditional material for scuppers was copper for its durability. Today it is stainless steel for an equivalent quality without the risk of robbery.

In terms of Energy Savings, day-lighting is one of the few initiatives that you can take that has a significant impact. These roof monitors allowed sunlight into the 2-story building through vertical south-facing glass, which was then controlled by the calculated placement of baffles so that direct sunlight was never a problem. The monitors were about 15' on a side and sloped down from a 7' high point. There were open areas in the second floor to allow sunlight to reach the first floor.
The glass in the roof monitors faced south to get the maximum amount of sunlight into the building all day long in a way that could be controlled. The monitors allowed that to happen in a way that skylights could not.
This project was built in 1997 by Dutch-owned candy company who had taken on the challenge of becoming sustainable by 2004. (They were bought by an Italian candy company before achieving the goal.)

Skylights can have a dramatic impact on the interior of the building. Natural daylight provides interesting light and can reduce the need for other artificial types of lighting.  

A linear skylight requires integration with the structure. In this case roof joists were enclosed by and included into the ceiling design without adding any awkwardness.

The key features of the detail are the:

• structural integration
• roof flashing and counter-flashing
• ceiling configuration and detailing to show off the skylight
• identifying other components of the skylight system

Roof Expansion Joints are customary where a new roof abuts an existing building, as in this case, where there is an expansion joint in the building, or where there is a change in plane of the roof. In this last instance an expansion joint is not always required.
Roof Expansion Joints prevent movement from damaging the roof. Movement is almost always the root cause of roof problems. After eliminating chemical incompatibility and physical damage causes, you are left with movement due to gravity, thermal expansion/contraction (of membrane or building), or shrinkage of membrane. 
Some roof membrane types are more susceptible to movement than others. If your project expects a life of more than 40 years, it is prudent to expect that the membrane type will change when re-roofing takes place at some point. 
In the roofing condition shown here, the new building had an EIFS finish that we did not want to flash to, so we tucked the counter-flashing under the EIFS. This tactic could be used to flash into an existing unsuitable surface, too.

Where there are multi level roofs or a tall parapet, you will need to flash the roof into the abutting construction. Extending the roofing, say EPDM, up more than 18"-24" invariably fails.


The detail below shows all the relevant issues. Although the sealant is a maintenance issue, it is easy to inspect and repair. Counterflashing built into the masonry requires less maintenance; but it is harder to determine if it needs maintenance; and it is harder to repair. 

Anchoring the counterflashing to the surface of the abutting construction only works if the construction is basically smooth. Where the abutting construction is not smooth, consider providing a smooth panel for the counterflashing to attach to and then starting the other construction.

Also see our detail Roof Expansion Joint - New To Existing