Exterior Receptacle - clapboard siding

[Ashful]

I need to mount one quad box and one duplex box, for exterior receptacles. Siding on barn is 1/2" x 6" cedar clapboard on 1" furring strips, over old siding. Entire barn to be spray-foamed on Tuesday, so this is my last shot at doing anything that's penetrating the wall.

Yes, I know I can mount exterior Red-Dot boxes on the outside, but would love to not have boxes hanging off the outside of the barn. Since the reveal on the siding is 4", less than the height of the average quad-box cover plate, I'm wondering if there's a better way to go than just mounting the box on ears, penetrating the wall. I do, at this point, still have the option to swap two duplex boxes, mounted horizontal, for the single quad... so that's a fall-back.

Related, I need to mount some gooseneck lights with 4-3/4" mounting flanges. Here, I'm thinking just 6" hole saw thru siding, use same hole saw to cut a 6" round slug of trim board, and mount box in trim board slug. Lights of choice are (broken link removed to http://www.barnlightelectric.com/gooseneck-barn-lights/gooseneck-lighting/the-original-warehouse-shade.html).

Ideas?

 

[semipro]

I don't like the way outlets mount directly in clapboard so I flush mounted an electrical box in a separate piece of 5/4 stock trim. Because the 5/4 stock is thicker than the bevel siding I installed flashing above. I do this for light fixtures too.

 

[Ashful]

Was hoping you'd comment, semipro. I plan to do the same with my lights, using a 6" hole saw to saw the clapboard (not thru sheathing), and the using the same hole saw to cut a 5/4" plug to fit the hole. This is for a fixture with a 4-3/4" mounting plate on a 4" octagonal box... haven't figured out how to drip cap a round slug, just yet.

For the receptacles, had to get it done yesterday, so I just bought 3-1/2" deep metal switch boxes, and routed thru both clapboard and sheathing. I slid them in from the outside, mounted a 2x4 on back side of sheathing, and screwed box (inside-out) to 2x4. Clean install, as my routing is meticulous, and I'm using the same cover you show above. Top edge and sides of cover will be caulked to siding before painting. Since I mounted horizontally in the middle of a clapboard (didn't want to cut courses), the the top of cover plate is about 1/2" below edge of the clapboard above. It would not be difficult for me to slide a sheet with drip edge up under the courses above the receptacles, but not sure it's necessary. What do you think?

 

[semipro]

It would not be difficult for me to slide a sheet with drip edge up under the courses above the receptacles, but not sure it's necessary. What do you think?

I don't think I'd have added the drip edge in my case had not the 5/4 board protruded beyond the face of the siding.
That said, I integrated the drip edge into my (liquid) water barrier (Tyvek) just like you'd do above a window or door. I'm not sure how you handled penetration of you water barrier but assume there's potential for any water that gets behind the siding to enter the wall where your electrical box penetrated the water barrier?
Assuming the metal switch boxes you used were the weathertight type, water entering through the outlet itself shouldn't be able to get into your wall. If you used a standard (non weathertight) metal box I'd be concerned about water entry through the many holes characteristic of those types of boxes. I wouldn't trust the simple foam gaskets and spring closures on those outlet covers to keep all water out of the box.

 

[Ashful]

I don't think I'd have added the drip edge in my case had not the 5/4 board protruded beyond the face of the siding.
That said, I integrated the drip edge into my (liquid) water barrier (Tyvek) just like you'd do above a window or door. I'm not sure how you handled penetration of you water barrier but assume there's potential for any water that gets behind the siding to enter the wall where your electrical box penetrated the water barrier?
Assuming the metal switch boxes you used were the weathertight type, water entering through the outlet itself shouldn't be able to get into your wall. If you used a standard (non weathertight) metal box I'd be concerned about water entry through the many holes characteristic of those types of boxes. I wouldn't trust the simple foam gaskets and spring closures on those outlet covers to keep all water out of the box.

Was thinking about that as I did this, yesterday. In my case, clapboard siding is hung as rainscreen construction. Basically, from inside out... framing, sheathing, tyvec, 1" furring, then siding. So, any leakage drains down back side of siding. Any penetration that can carry water to sheathing should drain down outside of tyvec. That said, I did use a standard metal box, as I figured water in the box is not something I want (I deal with that with my many receptacles set into various masonry walls around the property). Since I was cutting in thru siding at sheathing at same time, there was no opportunity to deal neatly with tyvec, but I can get in there to tuck flashing behind.

I initially figured any small amount of moisture getting behind that caulked cover plate should drain out of box in space between siding and sheathing, but there is honestly some likelihood it could go into insulated wall cavity, as boxes are angled back just a bit to match rake of siding at cover plate. After thinking this thru some more, I may open up lower edge of hole thru sheathing some more, and tuck a flashing under box, angled down and out. This way, any water draining out back of box can be directed back outside. This would be pretty simple to bend up and install from inside, before insulation goes in... just means pulling wiring and boxes back out, one more time.