Gutter installation

[Steadyhand]

I was reading about installing gutters on a mobile home. My place has the vertical metal siding and tin roof. I understand how to mount the gutters under the existing water channel system and bend it down into the new gutters. My confusion is with the sealing. I read to apply sealant either behind the new gutter system where it sits against the siding or apply it under the old gutter channel. I am not entirely sure where it was supposed to be sealed or why it needed to be sealed. I thought water would simply roll off the bent water channel and into the new gutters where it would be carried away. Is the sealant to keep water from getting behind the new gutter system where the water might work its way into the screw holes?

Also, do I mount these gutters by screwing them every couple of feet like I would a normal house?


My reasoning for installing the gutters is because I believe water is getting behind the siding from the upper J channel trim which is approximately a foot from the roof line. I found the rear corner of my rim joist was rotted out and water appears to be coming from above. Everything is sealed up with silicone already so that J trim is the only place water can be coming from. I already painted a sealant on the roof corner also to make sure water wasn't coming from there. New gutters will help keep water away from that J trim but it will not stop driving rain of course so I will have to figure out another way to seal that trim and hopefully keep it from looking too bad.

[Greg]

As far as sealant goes, do both that way you know it's not getting through there.
Depending on the age of your home water from the roof may or may not be to blame. If the ground under your home is wet that may be a factor or any holes in the siding.

Greg