Brown water stains spreading on a ceiling

Often not. Water travels along decking, framing, fasteners and insulation before it appears, so the entry point can sit several feet away and even on a different roof plane. The stain is useful evidence, not a location.

Possibly not. A stain that appears during a thaw after snow and never during summer rain is the classic ice-dam pattern, and the roof covering is frequently sound. A stain in cold weather with no precipitation at all is usually attic condensation.

Not until the cause is found and fixed, or it will return through the new paint. Stain-blocking primer will hide a stain whose source is genuinely resolved, but painting an active stain only delays finding out how much material behind it is wet.

Keep people out from underneath first. Controlled relief from below is sometimes the right call, but it is a judgement about how much load is up there and is best made by someone who can assess it. A ceiling holding trapped water can fail suddenly and heavily.

More than the stain suggests, usually. Wet insulation loses its value and does not dry readily, and sheathing and framing can stay damp long after the visible stain dries. Ask for the extent to be assessed rather than only the entry point repaired.

That is your insurer's decision, and it commonly turns on whether the damage arose from a sudden covered event rather than long-term wear or a leak left running. Document the dates and conditions and raise it with them directly and early.

Yes — a plumbing leak, a failed bathroom seal, an HVAC condensate line, or attic condensation can all produce the same symptom. A stain directly under a bathroom or a mechanical run deserves that check before assuming the roof is at fault.

Not reliably. Water can travel a long way along framing and insulation before it becomes visible, so a small visible stain does not rule out significant wetting above it, and a large stain does not always mean an active severe leak. Size is a weak proxy for extent.

Actively spreading during rain warrants prompt attention and safe containment. A dry, unchanged ring is not an emergency but should still be investigated, since a stain that dried once will typically wet again under the same conditions.

It can help the room air, but it does not reach wet insulation or sheathing hidden above the ceiling. Genuine drying of concealed wet material generally needs the area opened and assessed rather than relying on a dehumidifier alone.

Generally no, beyond containing active drips safely from the floor. Removing material yourself can disturb evidence useful for diagnosis or an insurance claim, and working near a wet, potentially weakened ceiling carries its own risk.

No. In a multi-story house, plumbing, HVAC, or a leak from an upper-floor bathroom or fixture is at least as likely a cause as the roof, and each of those needs its own investigation rather than defaulting to a roofing explanation.