Why is my roof leaking?

The five usual causes

Flashing. The most common by a distance, and especially likely if the roof has been replaced before and the flashing was reused rather than renewed.

Valleys. Where two roof planes meet carries more water than anywhere else. A valley shingled over rather than properly lined will find a way through.

Vent boots. The rubber collar around a plumbing vent perishes years before the shingles do. Cheap to replace, expensive to ignore.

Ice dams. A Maryland specialty. Meltwater refreezes at the cold eave, backs up under the shingles and comes through with nothing visibly wrong. The fix is ventilation and ice-and-water shield, not more sealant.

Storm damage. Lifted or missing shingles after a wind event. Worth photographing quickly, because it can matter for a claim.

What it usually does not mean

It usually does not mean you need a new roof. That is worth stating plainly, because it is the conclusion a lot of homeowners are steered toward the moment they report a leak.

The exception is age. If the shingles are curling and shedding granules across a whole slope, repairs stop holding and you end up fixing one spot while the next opens up. That is a genuine replacement situation, and we will show you the photographs that demonstrate it rather than asking you to take our word for it.

Why the stain is not where the leak is

Water travels along decking and rafters before it drops, so the mark on your ceiling is frequently several feet from the actual entry point and sometimes in a different room. Sealing above the stain achieves nothing.

That is why finding the cause is the real work. If someone tells you what is wrong without showing you a photograph of it, they are guessing.