Part H · the register

Find the AC Lines Before the Roofing Nails Reach Them

Refrigerant piping close to the roof deck can complicate a Kirkwood reroof. Here is what to locate before work starts.

Before you schedule a roof replacement on your Kirkwood house, ask whether any air conditioning lines run against the underside of the roof deck. A roofing nail can reach piping placed too close to that surface. The question matters even if the air conditioner works properly and the roof has never leaked. You are checking where the equipment was installed, not whether it needs replacing.

You do not need to climb into a cramped attic to answer this yourself. Tell the roofer where the attic access is, whether there is cooling equipment upstairs, and what you know about past additions or equipment changes. Ask for the accessible piping route to be checked before the installation date is settled.

Town roofing: the equipment below the Kirkwood roof

For a Kirkwood homeowner, the useful history may be the upstairs renovation rather than the age of the shingles. If cooling was added to a finished attic, or an addition received a separate system, mention that work during the roof visit. The contractor needs to know whether lines cross beneath the roof surface that will receive new fasteners.

The refrigerant lines connect parts of the cooling system. They are different from the large ducts carrying air through the house. Seeing ducts in an attic does not tell you where the smaller refrigerant piping runs. Likewise, finding the outdoor unit does not establish the entire route between that unit and the indoor equipment.

This is a recognized construction concern. The International Code Council's residential code revision history discusses protecting refrigerant piping near roof decks from nails and other fasteners. That document explains the hazard; it does not establish which code provisions apply to your Kirkwood address. Have the contractor responsible for any piping correction confirm the applicable requirements before choosing the remedy.

A nail showing below the deck is not automatically wrong

It is tempting to solve the problem by telling the roofer to use shorter nails. That instruction can create a different problem: shingles that are not fastened according to their installation requirements.

Atlas explains in its technical bulletin on shingle nailing that nails must penetrate sufficiently into the decking. Where the deck is less than three quarters of an inch thick, the bulletin calls for full penetration and at least one eighth of an inch extending through it. A visible nail tip underneath a thin deck can therefore be part of a correctly installed roof.

The practical conclusion is that piping cannot depend on roofing nails stopping inside the wood. Ask the roofer to identify the fastening requirements for the selected shingle and the actual deck. Ask the heating and cooling contractor to address any piping that conflicts with that work. Neither decision should rest on a guess made while the crew is already stripping shingles.

What an inspection can establish

An accessible attic gives the contractors a chance to see the underside of the deck and follow exposed piping. Request photographs that show both the close point and enough surrounding framing to identify its location. A tightly cropped photograph of a copper tube is less useful than a wider view showing which roof slope sits above it.

Have the inspection notes distinguish between an observed route and a concealed route. Piping that disappears behind a finished ceiling has not been checked merely because the visible section looks clear. The same applies where insulation, built-in storage, or a narrow eave prevents a view.

For example, suppose a line is visible above the upstairs hallway but disappears into the sloped ceiling over a bedroom. The useful finding is that the hallway section was inspected and the bedroom section remains concealed. Ask what additional access, if any, is needed to settle that uncertainty before roofing starts.

Make the attic hatch available and point out old renovation photographs if you have them. Leave moving piping, opening finished surfaces, and entering difficult attic areas to the appropriate contractor. Your contribution is the house history and access information, not a promise that every hidden line is clear.

What it costs

There is no defensible flat allowance for this issue without seeing the route. Checking exposed piping through an accessible hatch is a different task from opening a finished ceiling, correcting the line location, and repairing the interior afterward. A roof price alone cannot tell you which situation you have.

If a conflict is found, request a separate description and price for the proposed correction. It should identify who does the heating and cooling work, what access is needed, and who closes any opening. Ask whether checking system operation after the correction is included. That makes the expense understandable before you authorize it.

Also ask whether the roofing schedule changes. If another contractor must finish first, establish that dependency before materials arrive. In the St. Louis cooling season, discovering a piping conflict after tear-off can leave you coordinating roof protection and an equipment appointment at the same time. Finding it earlier gives you room to arrange the sequence.

Read any contract language about concealed pipes carefully. Ask the bidder to explain how an already visible concern will be addressed and how a newly discovered condition will be documented. A general sentence about hidden conditions does not tell the crew what to do beside a line that has already been photographed.

What to ask before the crew arrives

Keep the discussion tied to your house. These questions should produce locations, names, and decisions rather than a general assurance that the crew will be careful:

• Which accessible areas beneath the roof were inspected for refrigerant piping?
• Where does the piping disappear from view, and does that leave an unresolved concern?
• If a line is too close to the work, who determines and completes the correction?
• Who tells the roofing crew that the correction is finished?
• What happens if the crew exposes another line during deck replacement?
• Who provides the photographs and completion notes for my records?

Ask for the answers before the start date, particularly if two contractors are involved. The roofer and the heating and cooling contractor should be working from the same location information. A note that says only 'watch AC line' leaves too much interpretation to the people on the roof.

If the cooling changes during the roofing work

If the air conditioner stops cooling during the job, notify the roofing supervisor and contact your heating and cooling contractor promptly. State when you noticed the change and which roof area was being worked on. Timing is useful evidence, but it does not by itself establish the cause.

Ask the technician to document the diagnosis and any damaged location before repairs conceal it. Keep that report with the roofing photographs and invoices. Do not attempt to bend a suspect line away from the deck yourself or treat an equipment problem as something another layer of roofing sealant will resolve.

To discuss roofing at your Kirkwood address, call Keys Roofing at (314) 220-2333. If you have attic cooling equipment or a finished upstairs renovation, mention it when arranging the visit. Have the attic access location and any photographs of the piping route ready.