[ande3171]

I feel like this is a really stupid question, but I can't find an answer anywhere...

I plan to add a vent to my bathroom which will require work in the attic. What is the minimum recommened lumber to use to cross over the joists? I figure I would use 12" lumber. Just wondering if 1x12 is adequate or 2x12? I hate to have to buy and keep lifting and positioning anything heavier than I have to up there as I make the trek across...

 

[12penny]

ande....1/2" plywood would be okay. If you're big or joists are 24"oc then you might want to go to 3/4". No reason to buy dimensional lumber.

 

[jbfan]

ande....1/2" plywood would be okay. If you're big or joists are 24"oc then you might want to go to 3/4". No reason to buy dimensional lumber.

Agreed! Just make sure you position it right, or it will flip up on you.

 

[Just Bill]

The others seem to understand, but not sure what you mean by a vent. If you mean a bath exhaust fan, what you suggest is considerable overkill. Those vent fans normally use 4" round duct, whch can be rigid or insulated flexible.

 

[JCAHILL4]

I think he is saying he needs to climb across his attic rafters and wants to put some lumber down perpendicular to the ceiling rafters to walk across. In that case you would be fine with either plywood or a 2x12, even a 2x10 but I wouldnt buy 1xanything for walking planks.

 

[Scuba_Dave]

Just do not vent into the attic, the vent needs to exhaust outside

 

[ande3171]

Thanks for the help guys. I was thinking 2x12's might be better as I would probably have a future use for them once I'm done, but a couple sheets of plywood should get me there.

Yes, I plan to vent out the soffit.

 

[downunder]

I feel like this is a really stupid question

Had an instructor once who was giving the usual speech about no such thing as a stupid question in class. "If you're wondering it, someone else probably is also"- you know the story.

I liked his final point though. Stupid questions are a lot easier to fix than stupid mistakes.:thumbsup:

So ask away.

 

[sunjwd]

I am planning to run some coax and network cables in the attic
so this "walking in the attic" thread is interesting. (I had the builder
put in a 2" PVC "conduit" that runs from the basement to the
attic in this 2 story house.

I'm in southern Ontario so the attic has blown in insulation. It is
blown-in insulation and thick enough to cover the joists.
I was planning to lay planks perpendicular to the joists to walk on.
For me, plywood sheets are not really an option as the opening into
the attic is only roughly 2ft x 2ft.

The planks would squish the insulation under it.
Does anyone know if blown-in insulation will re-fluff once the planks
are removed?

 

[Gary in WA]

Yes, it does if you use a lawn rake, or similar. When you blow it in, it is compressed for shipment. Be sure to fire foam the tube, if a fire started in the basement, it would very quickly spread to the attic, with that fuse between floors. Be safe, GBAR

 

[jbfan]

The planks would squish the insulation under it.
Does anyone know if blown-in insulation will re-fluff once the planks
are removed?

Not in any attic I have worked in.

 

[AllanJ]

If there is not that much insulation above the joists and you plan to use the planking over and over, then you might consider attaching stand-offs to the joists and install the planking on top of that. Use sections of 2x3 or 2x4 (depending on height needed) on edge. Toenail to the joists or drill long pilot holes to countersink the nails or screws way down to reach through to the joist.

 

[sunjwd]

you might consider attaching stand-offs to the joists and install the planking on top of that.

I was afraid the answer was going to be something like that. That´s what I was thinking.

A lot of hassle to run some wire but good safety. Night mares of stepping thru some ceiling drywall.