It sounds like someone did some shoddy work on the last roof replacement.
Flat roof leaking at edge.
The tar may work for awhile but the leak will eventually come back.
Diagnosing the source of leaks on a flat or low slope roof.
This will act as a physical water barrier.
Then reshingle sliding metal step flashing behind the fascia board the trim behind the gutter.
Where water enters your interior space might not be exactly where the leak is because any water that penetrates a roofing membrane can travel for some distance until it finds a seam in the sub roof or sheathing and seeps inside.
Flat roof leak diagnosis repair how to track down the source of leaks in a flat roof how to apply roof sealants coatings to stop roof leaks.
At the gutter edge of the roof install a pre formed foam filler between the roof sheet and the gutter flashing.
Look for little cracks openings or breaks in seams in these flashings.
The flashing should eventually be re done or metal flashing needs to be used along with tar in the repair work.
This article describes the location of the leak source on a flat or low slope roof and the repair of a leaky flat roof by application of a roofing sealant.
Locating a flat roof leak.
Here are five critical control measures to use to stop a flat roof leaking.
Flat roof repair is made more difficult.
Locating flat roof leaks is hard as leaks on flat roofs go in any direction unlike a sloped roof.
Just like any roof a flat roof will develop leaks but since it s flat the water doesn t have anywhere to go but straight down.
Install a profile filler at the highest points under a ridge cap or apron flashing to stop water ingress into.
How to install an impermeable roof.
Leaks and moisture probably the most common problems with flat roofs leaks and lingering moisture are issues that can be dealt with effectively as long as you stay on top of them.
While finding a leak in a flat roof is easier than on a steep sloped shingled roof leaks can still be deceiving.
It should overlap another piece of ice and water barrier laid below all the way down to the roof edge.
Depending on how the roofs join you may have to cut a slot to work it in far enough.
And that roof edge is still a problem.
Check the edge of the roof.