Inspector’s Handbook: HVAC Condensate Discharge Lines

Working on old Capitol Hill homes, I commonly find problems with condensate discharge lines in many HVAC systems. Even when I find them currently functioning properly, they are often built out of code. The common code problems I find with HVAC condensate discharge lines are as follows:

1. Sizing — the building code requires 3/4″-minimum diameter piping to be used.

2. Materials — the building code allows for copper, CPVC, PVC, and polyethylene pipe to be used for condensate discharge drains.

3. Interference with other systems — condensate discharge drains are not permitted to enter into overflow pans, or drains for other systems.

Following the code allows pipes to discharge with lower tendency for backup and destruction from flooding caused by backups.

DC’s Code requirement for porch stair handrails… What the Code considers a Handrail versus a Guard

To get a BBL for renting a house and to pass inspections for construction and sales, DC homes are required to meet the 2006 IRC Code. But there are certain things in the code that seem to be missed in homes more often than found. Front porch handrails are one of those items.

The Code says the following:

AJ601.1.2 Handrails.Every required exit stairway that has four or more risers, is part of the means of egress for any work area, and is not provided with at least one handrail, or in which the existing handrails are judged to be in danger of collapsing, shall be provided with handrails designed and installed in accordance with Section R311 for the full length of the run of steps on at least one side.
R312.1 Guards. Porches, balconies,ramps or raised floors or faces located more than 30 inches(762 mm) above the floor or grade below shall have guards not less than 6 inches (914mm) in height. Open sides of stairs with a total rise of more than 30 inches (762 mm) above the floor or grade below shall have guards not less than 34 inches (864 mm) in height measured vertically from the nosing of the treads.
So, technically, every time you see a front porch stair with treads over 30″ above the adjacent grade, there is supposed to be a guard on the side (both sides if both sides are open to below). We see many many houses that do not have this, but many of them are just above the cut off of 30″.
DC started using the 2006 IRC on December 26th of 2008. See the full text at

Capitol Hill stone retaining walls with beaded grapevine mortar joints

The granite stone walls with beaded grapevine joinery, also know by some as toothpaste joints, are probably the most common single style of retaining wall in Capitol Hill.  Interestingly, some sources say they are not original to many of the houses and were in fact added in the 1920s. As a contractor and craftsman, I pay attention to the details of the neighborhood, especially when it comes to things with historic character.

Often, we will see the wall has deteriorated over time. Most were built without deadmen or weeps. And, often we will see that where they have been repaired by other contractors, the beaded joints have been haphazardly replicated. Sometimes we see that the lines have actually been painted onto the mortar joints like Pepé Le Pew’s girlfriend.  The true joint is original in its style and was constructed by tooling the joint while wet.

It isn’t easy to do it right, but it can be done.  Look out for a future blog where I will show how to re-create an accurate historic grapevine joint.

DSC09796 - Copy  DSC09794 - Copy  DSC09795 - Copy


Underpinning to Avoid Undermining an Existing Footing

When excavating below an existing footing, it is important to take provisions to prevent undermining the footing. Here in the city, this type of scenario occurs commonly when excavating for new additions next to existing structures. Class C & D soils are very common in DC. In soil types like this, an existing footing has an angle of repose that extends directly below the footing and outward to the sides.


Underpinning is the method to support the existing footing to avoid undermining the footing. Different methods of underpinning are available options, but common methods include needle beams, mass concrete, and mini-piled underpinning.