Replies

1. Expert Member
   MALCOLM TAYLOR | May 03, 2020 01:26pm | #1

   Nic,

   You use a mounting block. https://www.menards.com/main/building-materials/siding/siding-accessories/meadow-valley-7-x-7-fixture-mounting-j-block/9900000051078/p-1444439381448.htm

   You can make your own, or buy them in a variety of materials at a BB store or lumberyard. It needs a cap-flashing, although some of the pre-made ones come with integral flashing.

2. 
   grmp945 | May 03, 2020 02:53pm | #2

   Hi Malcom,

   Maybe I'm misunderstanding something simple. How would a mounting block help with integration into the zip sheathing? I could mount the electrical box directly on top of the zip sheathing and have the front of the box fit flush with a mounting block, but the problem would still be the back side of the electrical box not being flashed to the WRB.

3. Expert Member
   MALCOLM TAYLOR | May 03, 2020 07:26pm | #3

   Nic,

   You flash the mounting block, not the electrical box. That's the case whether the box is installed proud of the sheathing in a mounting box, or as is more typically the case fastened to a stud and just proud of the exterior sheathing. The assumption is the light fixture and gasket keep moisture out of the electrical box. It's the same situation with exterior outlets where the cover-plate provides protection against moisture. That's the big advantage of using a mounting box over just relying on the siding. It gives you a smooth, flat surface for the fixture gasket.

4. Expert Member
   BILL WICHERS | May 03, 2020 10:26pm | #4

   Ye olde electrician’s trick is to caulk the top and sides of the fixture-to-mounting interface with a releasable caulk like silicone, but leave the bottom unsealed so that it can drain. Don’t trust the gaskets on anything on outdoor electrical things — they never seal very well.

   Bill

1. Expert Member
   MALCOLM TAYLOR | May 04, 2020 12:17am | #5

   Most pre-fab mounting have have a cover that stops any water getting to the box. I've never had trouble either way, but I also usually locate exterior lights under some overhang.
   https://www.gescan.com/arlington-8141fgc-29571?utm_source=product_feed&gclid=EAIaIQobChMIgN6NhqyZ6QIVVh6tBh2rsQX1EAQYAiABEgLA7PD_BwE

1. Expert Member
   BILL WICHERS | May 04, 2020 09:16am | #6

   I’ve always seen the most problems when fixtures are placed such that water can sheet down the wall. Sometimes this is just due to how the building is, other times it’s from occasional wind-blown rain.

   Protecting the fixtures under overhangs is always a good idea when possible.

   Bill

5. Expert Member
   CARL SEVILLE | May 04, 2020 09:35am | #7

   Flash the wire to the WRB, then install a block with a hole cut in it the size of the electrical box that the siding will run into like a corner board.

   
6. 
   grmp945 | May 05, 2020 08:37am | #8

   Thanks all for your replies!

   After some searching I found a couple of good options that allow for integrating the electrical box into the WRB very well:

   Quickflash products:
   http://www.quickflashproducts.com/products_electrical.html

   Arlington FR series flanged fixture boxes:
   http://www.aifittings.com/catalog/siding-mounting-blocks/non-metallic-fr-series-device-and-fixture-box/

   I also found a flanged mounting block that easily integrates into the WRB and won't require using a sealant/caulk to flash it:

   https://sturdimount.com/products/

   Any opinions on which of these options you would prefer?

1. Expert Member
   Peter Engle | May 05, 2020 09:38am | #9

   I've been specifying QuickFlash products for years. They can be very helpful in solving the scheduling issues with utilities penetrating the envelope. The trades can rough-in their utilities, or a conduit sleeve for the utilities, and the carpenters can use Quickflash to seal the WRB/Air barrier to the sleeve. Then the sleeve is available to the trades to run their stuff through the wall at the end and simply caulk the interior of the sleeve. I've done some work with production builders who have been having good luck with this approach. Nice products.

7. 
   grmp945 | May 05, 2020 10:32am | #10

   One advantage I see with the Arlington flanged fixture panels is that it combines the flashing panel and electrical box into the same unit, whereas the Quickflash panels require purchasing specific compatible electrical boxes - and from looking at the list of compatible boxes, they are not always readily available.

1. Expert Member
   Peter Engle | May 05, 2020 01:13pm | #11

   Nic,
   I generally use the quickflash to either flash the cable or a PVC sleeve for later installation of the cable. Both of those are readily available. I don't love the Quickflash options for the actual junction boxes.