PLUMBING TOP OUT

Now that the framing is complete and the roof is installed, it is time to move inside your house and begin installing the “mechanicals”. This will include your plumbing, HVAC, electrical, and low voltage rough installs. In this article, we will cover the plumbing phase of the mechanicals, known as the “plumbing top-out”.

In the pre-foundation phase of construction, the plumbers would have run your main drain lines and tied into the main water supply line whether it was city water, co-op water, or a private well. Now it’s time to run all of the interior water lines through the home feeding from the main supply line. This will include running water supply lines to all sinks, showers, bathtubs, toilets, hose bibs, water heaters, washing machine boxes, refrigerator supply boxes, water softener systems, and any other fixtures or areas in your home that might require water supply.

In the past, these lines have typically been copper lines which are not flexible, require soldering to install, and can corrode over time. In the last several decades, many builders have made the shift to use PEX supply lines. PEX was created in 1968 by German scientist Thomas Engle and is a new form of plastic. Antioxidants are added to the mixture when the material is created that prevents it from breaking down, thus making it safe for water supply lines. PEX supply lines have several advantages over traditional copper lines including the flexibility to expand when the weather changes preventing busted pipes and leaks when used with proper PEX installation tools and PEX connection pieces. PEX is also flexible which decreases the number of connections needed to reach areas of your home, which limits the possibilities of leaks. Finally, PEX will not corrode over time and does not require soldering to install, which both decreases your initial cost of construction, and helps prevent future homeowner maintenance.   

During the top out, the plumbers will run their vent stacks through the roof (make sure you get your roof boots installed), run any extra drain lines to tie into the main drain installed pre-foundation, and insulate all of your exterior water supply lines. Depending on the energy code where you are building, they might be required to insulate all interior hot water supply lines, check local code and ask inspectors for clarification.

The final item the plumbers will do for you at this stage is to set your static water pressure test. Typically, a test ball is placed in the main drain to the sewer/septic system, and then the pipes are filled with water to check for leaks. They will also fill the bathtubs and shower pans with water to ensure these fixtures are not leaking. The city inspectors will require this test to pass your framing and mechanical inspection sometimes referred to as “Building Seconds” inspection.

Now that the plumbing top out is completed, the “HVAC rough-in” is ready to commence.