1.Years ago the standard was 4" Gutters, since the 1960's, 5" roll forming machines were developed and most contractors only have 5" machines, so since then, 5" has become your standard Gutter.
6" Gutters are now, or should be the standard in Gutters. Most Contractors don't have 6" roll forming machines, so they only offer 5" gutters because that's all they have to offer! 6" Gutters are one inch wider and one inch deeper, They hold approximately hold about 40% more water and some people say they hold as much as 167% more water. And in combination with a 3"x 4" leader, they let out about100% more water, can be installed with less pitch, keeping your Gutters more level for a superior look and Functionality. Water will always flow to it's lowest point and with a larger outlet for the 3"x 4" leader, have a much less chance of clogging, making it much easier to maintain and less of your precious time going up on your roof and keeping you safe from spending time up on a roof or ladder that only leads to dangerous work. So besides all that, they look and work 110% better. I usually compare them to a train set, 5" is your HO train and your 6" is your Lionel train set.
It depends on a lot of situations, such as the size of your roof, Houses are getting bigger and so are the roofs. We also seem to be getting bigger rain falls, Why, some say it's because of el nino, others blame it on global warming, but for what ever reason, it does seem like the rain falls are bigger and longer!
The Gutters also are the problem, if not installed properly or they don't use the biggest outlet (like we do!), the water just can't escape as fast as it is raining. Smaller outlets can't let debris thru the leader, making it easier for clogging of the outlet.
Another thing is trees, as houses get older so do the trees, meaning they have grown up and shed much more leaves then they use to.
The roof is to big for the size Gutter that you have on your home, the outlet may not be the right size and of course the Gutters are not big enough, all this and the trees around your house have grown, they may not even be your trees.
This could be a few problems, 1- your roof is to short, 2-your gutters are to small, 3- you need more leaders to drain more evenly, 4- your gutters might not be properly installed and last but not lest, you house could have settled and settled in the opposite direction.
The Helmet works on a capillary action, where the water gets siphoned into it. They usually are very costly and you still have to maintain your gutters. The leafless gutter works on the same principle but still must be maintained. Usually if you like birds and bees these are the gutters for you, they make a nice home for them. Screening usually keeps the big stuff out and are usually the least expensive of all the products, also they can be maintained the easiest. The best method is installing a bigger Gutter with bigger leaders and along with screening (the good screening) it's the least expensive, best looking and easiest to maintain. EVERYTHING needs maintenance!
Its usually one of two things, 1- your roof is to short or they did not put an under course when they started the roof and 2- The gutters are pulling away from your facia because of poor installation or they used a plain shank spike, Hidden hangers with screws are the best way to install the gutters and GUTTERGUY.COM only uses the stainless steel hidden hanger with a stainless screw.
The corner pieces and there are 3 ways to install corner pieces (miters) have to be sealed the correct way the first time, we usually use silicone and use a double bead in the miter, once the corner gets weathered or water gets thru, it's very hard to seal them properly, so it is imperative that the corner or miter is sealed correctly the first time or it probably will leak as long as you have your present gutter system. Do it right the first time or don't do it at all.
First and foremost, your home needs ventilation, this includes a ridge vent or some type of aluminum or copper vent, Gable vents are necessary at your peak areas and technically you need twice as much soffit vent as you do roof vent, Ice and Water Shield can be installed but this usually done when a new roof is installed.