Garage attic flooring

[Sigo]

Been lurking around for a while and taking in a lot of the great ideas. Now that I'm back from SWA, I'm looking to complete a few projects in the garage. First, I've got a small attic space above the garage that I'd like to put plywood flooring down so that it can be used for light storage. My question is this. The space has wiring that runs perpendicular to some of the joists. What's the best way to go about handling this so that I can secure the plywood to the joists. I don't want to have to re-run all the electrical. Thanks.

 

[bchee]

If allowed by code, how about a multifunction tool for notching?

 

[RaiderGrad]

I cut small notches in the top of my joists, laid the wires down in them and the boards on top. I had minimal wiring so my notches were less than a 1/4 inch deep.

 

[bchee]

http://www.fein.de/fein-multimaster/us/en/applications/interior_fitting.html

 

[logical]

I'd take the time to rerun the wire thru holes in the center of the joists. Notches will only get them directly under the plywood and still vulnerable to nails. The other option is lenthen them using junction boxes and route them around the area you are flooring.

 

[kbs2244]

The stress on joists is along the bottom edge.
If your wiring is Romex the shallow notch idea should work fine.
But do some careful measuring and drawings of their locations for reference when you are nailing.

 

[Randy_che]

They also sell small steel nail-in plates in the electrical section of your favorite big box to prevent nailing into a wire laid in a notch.

 

[KEH]

My house was built and wired when I decided to floor part of the attic. Nothing fancy, just for storage. Wireing was on top of the joists. I cut strips of 3/4 inch lumber to fit on top of the 2/6s between the wires and put plywood on top of that. No problems with checking out the direction of the wireing and nailing through the plywood to avoid the wires. This had the advantage of not weakning the 2x6s.

KEH

 

[737mechanic]

Just notch the tops and drop the wires in and nail the boards down. Make sure you don't nail through the wiring.

I did this over 10 years ago and have not had any problems at all and I have thousands of pounds of junk in my attic.

P.S. My ceiling joists are 2x12's.

 

[mmhouse]

I'd take the time to rerun the wire thru holes in the center of the joists. Notches will only get them directly under the plywood and still vulnerable to nails. The other option is lenthen them using junction boxes and route them around the area you are flooring.

You can put metal nail plates over the wiring to protect it. They're readily available and cheap.

http://images.orgill.com/200x200/6481261.jpg

 

[WNYflyer]

I believe this is current code for notching solid wood joist.

R502.8 Drilling and Notching: Notches in wood joists, rafters or beams shall not exceed 1/6 of the depth of the member, and shall not be located within the middle third of the span. Notch depth at the ends of the member shall not exceed ¼ of the depth of the member. The diameter of a hole cut in wood joists, rafter or beams shall not exceed 1/3 of the depth of the member. The hole shall not be closer than 2 inches to the top or bottom of the member or any other hole in the member.

 

[Colin-Roberts]

since it's only storage why not run chases like raised 2x2 3 sided would box or something to cover and protect the wires and them just plywood on both sides of the chase

 

[Sigo]

Thanks for all of the input. I'm still weighing all the options. Much appreciated.

 

[Boyd]

I plan to do the same project soon, but my problem is a little more complicated. I have a ton of wiring going across my 2x12 joists...diagonally. Additionally, There are two huge 4x12 beams on top of the joists, spaced about 12ft apart, that the wiring goes over.

I haven't thought of junction boxes like someone above mentioned. Would that go against code, to have umpteen junction boxes in the attic?

 

[Wingnut65]

Even if it is allowed by code, some house inspectors will make note of the truss cords that may be compromised with cuts in the top cord...

I just finished installing a floor in my attic. I cut all my plywood to 2' widths to fit my truss spacing, then went up in the attic and planned the location of each piece. I had to cut notches in the plywood to fit around the truss vertical members. And, every place that I had cables or wires crossing the truss, I used a 1" forstner bit to drill a line of partial holes to put a recess in the bottom of the plywood to allow space for the cable to sit without getting pinched. When I set the plywood I just made sure the cables were loose in the plywood recess.

This method solves the problem without cutting any trusses that may cause cencern to anyone in the future.

 

[Falcon67]

Why not just lay 2x4s on top of the joists with gaps for the wiring, then lay the flooring on top of that?

 

[Auzivision]

I used cheap 1X4 to lay across the joists, then marked where the wires crossed so I wouldn’t accidently screw into one. It was really was easy. Also, I them at the seams by attached one along the top of the joist as apposed to the runners at 90 degrees… much stronger.

While I was at it, I built a shelf on one side because there were far too many wires and I wanted a back drop to keep stuff from falling off into the tiny space.

Following is the end product:

 

[jam022316]

Like a lot of other folks have said, instead of notching I would run 2 x2's or something along to protect them and **** up against them. Unless you want a solid floor then maybe the leverage idea such as laying 2x4's across and then plywood on top of that.