Enlarge gutter downspout opening
 

Our house has 5" gutters on the upper, main portion of the house. The previous owner replaced the lower roof gutters with 6" gutters, because parts of those handle more water because they get some water diverted from a downspout from the upper roof into them. The larger gutters work well. The smaller gutters on the main house roof also drain a lot of rain water, and in heavy downpours, usually overflow. Each time I go clean them, there is a collection of small sticks near the downspout, which I remove, but the bottleneck is a very small exit from the gutter to the downspout. The hole is probably not even 1.5 x 3". The downspout is 2 x 4" by my rough estimate. That means there is a much smaller hole than the downspout could accommodate. Simply enlarging the hole transition to the downspout would improve flow, and freedom from bridging.

Can the exit holes be enlarged? It would appear the alternative is replacement of all the main house upper roof gutters with larger ones, which is not an attractive option due to the amount of gutter.

It all depends if the hole in the gutter has a manufactured outlet or if it has just had a cut made to the gutter pan and the bottom of the gutter metal pushed down to secure the down pipe to it. If it doesn't have a metal collar you can get one from the hardware or big box stores, make a outline on the bottom of the gutter, cut out the metal, insert the outlet from above into a bed of gutter caulk, pop rivet the outlet to the gutter and reattach the down pipe with pop rivets. Installing a gutter screen will help to keep debris out of your gutter. Great DIY project if you have access to a ladder and some tools.

Be careful when working on a ladder over another roof deck, be sure to tie off the ladder to a gutter hanger.

Good luck!

I agree, except I would recommend you having a licensed and insured contractor. The last thing you want is to get injured over some gutter work.

Just do it yourself!!! Contractors are only needed for those things you either can't do or can't do in a timely fashion.
Take your time and have fun.

Bingo, thats why we are all here:trophy:

I'm always amused when someone in the XYZ business makes a case against XYZ DIYers.

Given that 40,000 people a year are killed in the US in auto accidents, anyone that does not hire a professional driver would appear to be reckless.

2"x3" downspout outlet fittings
 

Sure. You have 2"x3" downspouts. Apparently someone did not use the proper outlet fitting which is made to match the 5" gutter and provide a hookup/attachment of the 2x3 spout. 2x3 downspout outlet fittings (mill finish) are very common and in stock wherever gutters and spouts are sold. Simply trace the opening on the inside of your existing gutter and use aviation snips to enlarge the hole in the gutter, and then pop rivet the flange of the fitting (with sealant) to the gutter - from the inside. Downspout attaches to the outlet fitting with pop rivets or zip screws.
Ron

5" & 6" gutters
 

By the way, 6" gutters have 3"x4" matching spout size, and 5" gutters have 2"x3" matching spout size.
Ron