Blue Water Dripping Off Siding

Water runs down the siding and can collect in the j channel.

Blue water dripping off siding.

J channel is a poor design if not flashed well it allows water to get in behind siding. Mild soap and water with a soft scrub brush is sufficient for general dirt and grime. It can get behind the siding and cause serious problems within the walls as well as leakage in the basement or crawl space. Significant water buildup can lead to leakage behind the channel and siding.

Water should not be allowed to run down the siding. During a very heavy 2 days of rain water began running from between pieces of siding. Blue or green staining occurs exclusively with copper pipe and fittings including brass which is copper plus. Rainwater leaking from a gutter ends up behind siding and causes a wall to rot.

Since water runs downward unless it s being driven by strong winds the standard method for creating water resistant vinyl cladding is to start at the bottom and work up. The extra thickness of the vinyl. If you train the hose so it shoots water upward into the bottom or vertical laps of the siding it might. If you see the stepflashing drain behind the siding the paint under the butts will keep it from draining out and still if the lap is below the first stepflashing all the water will drain behind.

The shingles should be hanging about 1 4 inch to 1 2 inch beyond the drip edge so this may be your problem. At some point in the past an owner had vinyl siding installed over old siding. If there is no way for it to drain the channel holds this water along with any dirt that was on the outside of the house. Some areas were extremely heavy while others were just a single streak.

Bear in mind that vinyl siding is designed to keep out water that falls from the top down.