Do I have a roof leak and can I test with this meter?

No meter is used.
Any roofer or inspector climbs into the attic and looks for water stains on the underside of the roof to determine if there is a leak and where it is.

@kritiper How do they know if it’s old or active?

I just measured the stain to see if it grows. It looks bigger to me, but I really don’t know. I didn’t study it well enough when I first saw it. It just poured all day, but I’m alone so I’m afraid to climb into the attic myself, I have a regular latter not a proper attic latter. The drywall doesn’t feel wet I don’t think. The drywall is cold so it’s hard to tell. The air conditioner blows in that direction.

Why not ask if someone else from the roofers can come out and inspect it?

@janbb I’m thinking about doing that. Or, maybe paying an inspector for peace of mind. I could also ask a friend to spot me and climb up there myself.

@JLeslie The insulation will be wet.

@kritiper I find it odd he didn’t see any sign of a leak. That means to me he didn’t look hard enough. If it’s an old leak the signs should still be there should they? When they “replaced” the roof it was the shingles not the entire wooden structure.

Insulation gets moldy fast, so I want to be sure it’s ok up there.

@JLeslie Look closely at the ceiling where you suspect the leak. You should be able to determine if it is wet or dry.
Yes, if it was an old leak there will still be evidence of it. The water creates a stain on the wood.

Sometimes it is possible to simply put down another layer of new shingles over the old unless there is already two layers. Then all shingles have to be removed and the tar paper (the black stuff, usually) may be replaced as well.

I had a stain on my ceiling but it was due to a cat or squirrels nesting in the attic insulation. Their warm bodies creates a damp discolored spot on the ceiling. Make sure no animals can get up there!!

@kritiper The guy told me to spray with watered down bleach to fade it.

I never hear anything running around in there and I don’t have any trees in my yard. Not that It’s impossible, I’m just saying I don’t have the circumstances that usually allow animals in.

Next time it rains just check the mark to see if it’s wet.

Don’t wait… if there’s a leak, there’s probably already mold. Get the roofer AND an inspector up there soon!

I hope it’s old.

@cheebdragon It rained like crazy the last two days, and I think it is the same. I just outlined it with a pencil. It didn’t look wet at all.

@Cupcake I just talked to my inspector from a few years ago and unfortunately he retired, but he told me what to look for. I still might call someone else to look at it. I have to deal with it next week, too much to do now.