I need some advice installing back porch lighting

[lzicc]

I just closed on a new house a few weeks ago. The back porch does not have any lights. I can tap off a junction box in the attic, but am trying to figure a way to run the wires. The house is vinyl dutch lap siding. Underneath the siding is foam board then the 2x4 structure. I thought about pulling the siding off from the area that I am going to install the lights. I could cut a large enough square section of the foam board out to give me room to install my jbox and run my wire up to the attic. Once I run the wire, I can replace the foam board and tape the seams where I cut it, then replace the siding. The house is a single story house. Does that sound like the best plan of attack? My concern is weakening the structure by cutting and replacing the foam board, but the foam board doesn't really have any structural properties.

 

[GLyford]

Are you after something decorative, or just functional?

If you just want something functional, it might be simplest just to use an outdoor rated junction box (usually have your choice of white, gray, or black) surface mounted on the siding over the doors (there should be a header there behind the siding). Mount it just "snug"...if you want to get fancy, you could get one of those light mounting blocks with the j-channels and cut it into the siding. The run conduit up the outside to where you can either run it into the soffit (if there is one) or a "pull" elbow into the attic space.

Decorative will require a nice mounting block, cutting the siding, mounting a junction box inside the wall (if you are worried about support, you could use one of the "fan rated" ones with the bracket that expands inside the hole to the studs on either side of the stud bay). If you are going to be cutting and removing a section of foam for a box, you could also cut an opening large enough to put a 2x4 cross bar between the studs to help support the box. While a little more work, it's a lot cheaper than a fan box.

And of course, you'll likely need another box inside for a switch, right?

 

[MMalabama]

Have you thought about where you are going to put the light switch yet?

 

[jfh28]

if the house is a one story and you're just looking for light then the easiest way is to install a flood light centered above the door in the soffit......this makes the wiring and mounting easy and you don't have to mess with the siding or insulation at all......you can also get it with a motion sensor so it will come on and off on it's own........foam insulation does not have any structural properties so hopefully there is something solid behind it though like plywood or osb to provide bracing for the framing.......cutting the insulation will effect the thermal properties of the wall so if you do go that route make sure you seal up around the mounting box thoroughly.......Jack

 

[lzicc]

I will use a vinyl mounting block for the outside light. My main dilemma is running the wire. If you look at the picture, there is an outdoor plug on the left of the wall. I can tap off of that for power, but I need to be able to get the wire from that box to the new box that I will install just left to the door in the picture. The switch for the light will be on the other side of the wall on the inside of the house. I will install a light on both sides of the door, and from the first light I install, I can run up into the attic to get to the second light I am install. My question is pulling the siding off of the wall, cutting the foam board to have access to the cavity of the wall to run the wire, then replace the foam board and siding. It seems like the easiest way to run the wire unless there is a better idea.

The basement ceiling is finished drywall, so I have no access from the basement.

 

[/pine]

My question is pulling the siding off of the wall, cutting the foam board to have access to the cavity of the wall to run the wire, then replace the foam board and siding. It seems like the easiest way to run the wire unless there is a better idea.

Unless there is unknown or extenuating circumstances...this is the way most professionals would approach the issue...there may be some fire blocking in the wall that will have to be drilled etc...
They make special slip tools that will help remove the siding...

Good Luck...

 

[RNeumann]

Are you after something decorative, or just functional?

If you just want something functional, it might be simplest just to use an outdoor rated junction box (usually have your choice of white, gray, or black) surface mounted on the siding over the doors (there should be a header there behind the siding). Mount it just "snug"...if you want to get fancy, you could get one of those light mounting blocks with the j-channels and cut it into the siding. The run conduit up the outside to where you can either run it into the soffit (if there is one) or a "pull" elbow into the attic space.

Decorative will require a nice mounting block, cutting the siding, mounting a junction box inside the wall (if you are worried about support, you could use one of the "fan rated" ones with the bracket that expands inside the hole to the studs on either side of the stud bay). If you are going to be cutting and removing a section of foam for a box, you could also cut an opening large enough to put a 2x4 cross bar between the studs to help support the box. While a little more work, it's a lot cheaper than a fan box.

And of course, you'll likely need another box inside for a switch, right?

Go with choice one from this post. The exterior box will either have zero conduit (if mounted at or near the top of the wall) or very little conduit down to the box. The other option is to mount a box to the soffit.

If that won't work for you you will want an "old work" electrical box that can be cut into the wall without disturbing additional siding, foam etc. Once you cut the siding for the old work box, drill through the top plate into the attic and chase the wires down. See video for details.

How to Pull Cable Through Existing Wooden Walls - YouTube

Btw YouTube has several on this topic.

 

[RNeumann]

I will use a vinyl mounting block for the outside light. My main dilemma is running the wire. If you look at the picture, there is an outdoor plug on the left of the wall. I can tap off of that for power, but I need to be able to get the wire from that box to the new box that I will install just left to the door in the picture. The switch for the light will be on the other side of the wall on the inside of the house. I will install a light on both sides of the door, and from the first light I install, I can run up into the attic to get to the second light I am install. My question is pulling the siding off of the wall, cutting the foam board to have access to the cavity of the wall to run the wire, then replace the foam board and siding. It seems like the easiest way to run the wire unless there is a better idea.

The basement ceiling is finished drywall, so I have no access from the basement.

Don't do this! The drywall is 100x easier to repair and when finished you will never notice. The siding won't end up that way.

With a switch on the inside and the use of "old work" boxes this is actually fairly straight forward and shouldn't require siding or drywall repair.

 

[MMalabama]

I agree with pine, about the only way to do this properly is to remove the siding, cut the external sheathing, then run wire to new light switch box, then to new junction box, replace/fill in sheathing(foam board), install new mounting block, then put siding back on. If it would be easier on you, you could just take a 4" hole saw and drill into the foam board so you can get your hand in there to help fish the wires, that way you wouldn't be cutting out the whole cavity, when you are done just back your plug with a short piece of 2x4 and put the plug back in the hole. Still need to trim out for the mounting block though, looks way better than trying to screw a fixture down over lapped siding.

 

[lzicc]

I think that is the best way also. It's weird that I can pull the siding off to do this, almost too easy, but I wanted to check to make sure I'm thinking the right way. This will be easy to run the wires and not be messy at all. Once I get the siding back on, no one will ever know.