A drip beside the chimney, the wall or the vent pipe

The code describes how a joint is built, not how long it lasts. Along a taller wall, base flashing runs in one piece or in steps, and the code sets a minimum of four inches each way. Its job is to hand the water back to the roof or the gutter. Pipe and chimney flashing follows the shingle maker's printed instructions.

So the useful question is not how old the joint is. It is whether the joint matches that description. Ask the roofer to say which parts are there and which are missing.

You can help by noting what you can see from the ground. Is there a bright strip of metal at the base of the chimney, a bent piece at the bottom of the wall line, a collar round each pipe? Write down what you spot, and say what you cannot find. The roofer starts with your list and then looks for the rest.

Where a roof meets a wall, a kick-out at the bottom sends water into the gutter instead of down behind the siding. Without one, water can run behind newer vinyl or brick veneer for years, because those materials do not peel and blister the way old paint does.

If your drip sits under a wall line, tell the roofer, and ask if the wall has a kick-out. A repair at the joint that skips this piece is a repair that may need doing again.

A chimney wider than 30 inches across the slope needs a cricket, also called a saddle, on its uphill side. The cricket splits the water that runs down the roof and steers it round the chimney. Without it, water stacks up behind the masonry and works at the flashing.

Ask whether your chimney is wide enough to need one, and whether it has one. A narrow chimney may not, and the roofer should say so plainly.

Every pipe, bath fan hood and skylight is a hole cut in the roof, and each needs its own flashing. When one drips, the answer is rarely a bead of sealant across the top. It is a look at how that piece sits in the roof around it.

Tell us which of these is nearest your drip. If a bath fan sits close, add where it vents, because a fan that ends in the attic can cause a stain that looks like a leaking hood.

Sealant looks like a quick answer, and it can be a fair one for a small gap. But a joint that is built wrong, with a missing kick-out or a flashing piece that is too small, gives sealant nothing solid to hold. Ask the roofer what is under the bead before anything goes on top.

Ask too how far the roofer will look beyond the spot you pointed to. Joints often share a weakness with their neighbors, and a drip at one chimney corner can sit beside a problem at the other. Your question gets that into the proposal as its own line.

Finally, ask what is behind the joint. If the wall wears newer siding, the roofer may need to lift a section to see the flashing, and you should hear that before the visit, not on the day.