Rain diverter
 

I'm preparing my house to be painted. I just had a 6' x 12' section of rotten siding replaced on the rear. The cause of the rot is rain falling from the roof onto the small roof over the back stoop and bouncing back onto the siding. Note that the rain is falling from two different levels due to the setback of the dormer.

There are no gutters on the rear of the house. They were removed by a previous worker who told me they were causing ice dams (removing them made no change in the ice dams). Strangely, the siding to the right of the door was not affected. We removed all rotten siding and underlayment and covered the new plywood with bituthene.

To prevent this section from rotting again, I would like to place some kind of diverter on the little roof over the stoop. Any recommendations as to the type, material, and placement of the diverter? I will address the lack of gutters in a later project as I can't do everything at once. Thank you!

Where would you be diverting it to?

Away from the house is all I know. If I go bankrupt from increasing energy costs I could divert it to a rain barrel, I suppose. As a matter of fact, that's not a bad idea.

A diverter is usually aluminum and placed within the shingled portion.

A section of gutter... even if you chose to remove it in the winter... could direct it toward either a rain barrel or a downspout with a splash block or piping system that would move it away from the foundation.

The gutter above the doors at our Bristol location freezes solid every year and creates problems... we intended to extended it and add heat cables.

But I think we are better off just removing it for the winter and using sand and salt.

Home Depot in Tilton has do-it-yourself rain gutters with a downspout that drains the water into a 100-gal rain water storage tank for watering the lawn & garden ...... later on, some time .... http://www.homedepot.com/p/100-Gal-G...5964/316107600 .... for what seems like a reasonable price.

You could install a diverter on the roof of the shed dormer made of flashing like in this photo. It could keep water from hitting the roof over the stoop. This, however, may cause additional splashing onto the lower 1st floor siding. It already looks like paint pealing there. Looks to me like gutters is the solution.

One way for damage to siding: the flashing at the intersection of the little roof with the siding may have channeled water under the siding.

Alan

The places where a roof slope intersects a vertical wall must have step flashing on the wall at each course of roofing, or an equivalent installation for keeping water from getting under the courses of wall siding. At each place where an intersecting roof slope ends in the middle of a wall section, such as at the upper right corner of the red rectangle drawn on your photo, there should be kickout flashing at the lower edge of the roof section, to throw the water out away from the wall siding below. Do a search on "kickout flashing" and you'll see a great many commercial products and videos showing installation. You can fabricate your own flashings from sheet metal.

Here is but one reference, with video and diagram: https://www.americanflashings.com/jd-out-flashing

Here is another article, by Mike Guertin, a frequent contributor to magazines like Fine Homebuilding and Journal of Light Construction: https://www.jlconline.com/training-t...n-overlooked_o

Dick, thank you for this information and the links. So I would place kickout flashing in this area?

Attachment 17686

Dick, is this the right shape? https://www.homedepot.com/p/Amerimax...KOWH/203208108

Install like this?

Attachment 17687

If the damage to the wall is the red rectangle to the left of the door in your first photo, then the place where the lower edge of the roof over the door meets the wall is indeed where the kickout ought to go, as indicated in your second photo. However, that shot from the Home Depot seems to show installation of the flashing over the wall siding, with caulking to (hopefully) seal the top of the flashing to the siding. When at all possible, roof and wall covering layers ought to be "shingle-lapped", with all successively higher layers lapped over the tops of lower layers. This is shown in the JLCOnline link I gave. Actually doing this in a retrofit situation can be difficult, but sometimes getting a long-lasting installation does involve a bit of "wall surgery." You probably can find some decent retrofit videos.

Thanks, Dick. The how-to photo was from a different website. I think my handyman would not be pleased to have to lift up any siding, which he just finished installing. I'll study your other link.

The kick-out would be under the eave on the stoop, and on the sidewall of the dormer. It wouldn't hurt, but will not stop the water from splashing back against the siding once it hits the ground.

Sooner or later, you will need gutter the total length of the main roof.

The paint peeling under the window suggests that water may be getting behind the siding... and that something like a hydrogap or homeslicker was not used.
I can't tell from the photo if the clapboard was properly primed on all faces, or if it was properly caulked.

John, the worst rotting was at about the height of the window, right where you would expect water to spill from the entrance roof onto the siding. It wasn't as bad at ground level. I have stones next to the house to help with splashback (I hope it helps). The area where the dormer meets the roof seems less likely to send water to the affected area as it would flow straight down and out, less likely to the right. Still, you and Dick make a good point about the need for flashing where the roof meets a sidewall.

Yes, the new siding was primed on all faces. Did it myself, two coats. Yes, everything was caulked---I finally found a skilled handyman. This is a 1929 house, so other than this new siding, the rest of the house doesn't have any special waterproofing. The reason for what looks like peeling paint is that I've started scraping that wall to repaint the whole house. Gutters are on the to-do list.

Here is another article, showing a custom formed flashing for up where the dormer wall meets the roof: https://www.greenbuildingadvisor.com...-roof-flashing

And another: https://www.finehomebuilding.com/pro...keep-water-out

The picture shows what appears to be missing paint from the siding under the window?

Good eye. That was the one error the worker made---he accidentally nailed the board unfinished side up. Maybe there was a little bit of rot there. The other patches are places where I'm scraping.

If it was primed on all faces, he shouldn't have had any side that could be applied ''unfinished'' side up.

Unfinished meaning rough.

It should be primed on all sides including any cut ends.
Also it should have a drain channel behind it and be caulked at the base of each clap and any vertical joints.

If not, you will trap water behind it and the wood will absorb the water creating future problems.

Ice & Water Shield under Vinyl Siding will solve a lot of problems.
But, of course, it looks like hell.

That's not such a good idea for a large section of wall, in this climate. That puts a vapor barrier on the outside of the sheathing, which presents a problem in winter. Water vapor diffusing through the inner wall surface (eg. sheetrock) or carried by air leakage from the inside into the wall cavity can condense on the back side of the cold sheathing and be absorbed into the wood. If the water transport rate is low enough, the sheathing will pass the water slowly to the outside world. But that can't happen if I&W is outside the sheathing, so a damp wall cavity can result, unable to dry out, and rot or mold can develop. The only exception to avoiding a peel & stick vapor barrier product over the sheathing might be if closed cell foam were applied in sufficient thickness over the inner side of the sheathing.

Vinyl siding on the outside of a wall actually is fairly good, from a building science point of view, as its very nature provides a vented air gap beneath the outer surface. New vinyl siding products also are quite decent in appearance. Naturally, a WRB (water-resistive-barrier), such as housewrap, should be applied between sheathing and the cladding.

Peel & stick coverings such as I&W Shield have their place above the lower two feet of a vented roof deck, per code, to protect against ice dam damage.

Hey ..... here's a website ..... https://upcycle-products.com ..... that will sell and deliver rain barrels for storing rain that comes down a roof, and down a downspout into the big barrel.

Some more info on rain barrels ...... https://apcc.org/news-events/events/..._aid=697896961 .... rain barrel photo gallery

Sometimes it's just a lot less of a project to go with a rain barrel as opposed to a gutter or downspout that pours water onto the ground or onto a paved driveway. It may become a new item at home that you start to appreciate after having it for a few months? I recently noticed a large municipal building that is home to their town clerk, police dept, fire dept, and public meeting room that uses a single rain barrel to collect water that drains off one small roof section with a garden hose attached for watering their small flower garden out front. Is what you see, outside, when you visit the town clerk's office. Was kind of interesting to see that ..... a gray rain barrel with a garden hose.

The door roof.

Change to a flat (tilted) roof. To send that rain water away from house.