There are a few elements that come into play that cause water to run behind the gutter.
Why water is dropping tjrough my gutter withoit rain.
Damaged or absent drip edge.
Capillary action is a water activity in which water adheres to a surface and follow the surface around.
This then pushes the guttering out from the roof line by 9 17mm.
When these become loose they can cause small leaks to develop around the fastener with the result of water pouring out of the rear of the gutter and directly onto the fascia.
Standing water in gutters eventually will rust galvanized steel seams or seep through the seams in aluminum gutters.
This can be frustrating and also creates a dangerous situation on porch steps during freez.
Without looking at the roof it seems that the water is missing the guttering because perhaps the previous owners may have had new fascias overlaid onto the old.
If the gutters look clear run a hose and fill the gutters with water.
First check for signs of standing water and sagging.
Assuming the gutters have the correct slope the main reason for overflows is that the gutters are full of debris and need to be cleaned.
If the gutters are clogged it s possible that the water is overflowing the gutters and this is contributing to the leak.
If the gutter is clogged some of that water will back up on the roof soaking it.
If your gutters are leaking the prime suspects are the joints between sections.
Gutters are supposed to direct water away from your roof and into the ground.
The problem is most often a simple gutter clog or build up of plant debris which can be easily remedied by cleaning your gutters or freeing the clog to allow for adequate water flow.
Have rain water dripping out from between your facia and gutters.
Any rainwater or in sparodic areas then simply misses the gutter.
The first cause is when the roofing material is installed many roofers will not extend the roofing material past the roof edging or drip edge.
Some of the water may leak behind the gutters down towards the soffit and the fascia.
And it doesn t stop there.
The gutters are affixed to the fascia boards using some form of screws nails or hangers which are usually driven straight through the side of the gutter itself and into the boards.
When water drips between the fascia and the gutters the problem could be a compromised drip edge but it s also possible the gutters are overflowing.