Attic Flooring

[ghost]

I want to put some flooring in my attic for some additional storage. Should I go with the plywood route or with something like Attic Dek? There are pro's and con's to both.

A big problem I have is with the insulation, which is blown. Because the insulation is blown, I can't see any of the joists. I can see some cross beams, but that is about it. How do I combat this situation? Can I move the insulation? A co-worker of mine was told not to compress the insulation so you can get to the joists. Is that true?

 

[CaptainEd]

i floored out my attic with 1/2 or 3/4" plywood across the beams and it worked out great.

 

[Orangeblood]

3/4" plywood. Find the first joists and the others will be evenly spaced. Be careful over can lights and/or HVAC and (possibly) gas/electric lines.

 

[EuroHorn]

I saw a show on this the other day (I think it was this old house). They did say that compressing the insulation was not good, as it reduced the effect. They built a small platform for storing things that was raised above the insulation

 

[TheFied]

I did it in our garage. 2 sheets of 1/2" plywood. But the area above our garage is empty so there was no insulation (or very little) so we didn't need to worry about modifying the insulation.

We have probably 20 feet deep by 10 feet across done. The christmas tree is up there (in a tree bag) as well as all my baseball cards, some old magazines in a trunk, some spare tile we had, and a bunch of plastic storage boxes. My wife does not want silver fish so no cardboard boxes.

 

[ghost]

Yeah, a friend recommended 2x4's and 2x6's and putting OSB over it. I have high ceilings so I am not sure how I am going to get plywood/OSB into the attic. Did you all cut your sheets prior to installation or were you able to take the entire 4'x8' sheet into the attic?

 

[TexasEd]

yes, you need to raise your decking up to prevent compressing the insulation.

You can run 2x4s perpendicular to the joists to raise up the nailing surface for the decking.

Be careful of the additional weight from the decking and the storage boxes. The result can be a crack in your walls, ceilings or even in exterior brick façade if you have a 2-car garage and it sags over the door.

 

[CaptainEd]

i measured and cut everything prior to getting in the attic. all i had up there was a drill and screws.

 

[brntorng]

First of all, do not compress your insulation unless you want higher utility bills.

I attached new 2x4 joists between braces and above the insulation. Then over the new joists I laid down 3/4" plywood which was cut to size (including cut-outs for the braces) before taking it to the attic. Depending on your situation you may be able to leave the plywood in a full sheet or you may need to rip it into 24" or 16" strips depending on how much room you have to maneuver the plywood. Definitely a job for cool weather. BTW, don't store Christmas candles in the attic or you'll just find a grease spot a year later. Don't ask my wife how she knows this.

 

[wolfman]

I went to Home Depot and bought a couple of 4'x8' sheets of plywood. I had them make 2 cuts in each making them into 2'x4' sections. It made it easier to take home too. I screwed them to the joists in the attic. Was not too hard. There is no insluation in my attic in the area over the garage where I put the sheets so I didnt worry about insulation under the wood.

 

[NCAAFBALLROX]

The Orange Despot sells pre-cut 5/8" x 2' x 4' tongue & groove panels.

3/4" = Way heavy & way overkill.

If you are going to use 2x4's, you should be careful not to lay them flat (i.e. on the 4' side) because the wood will bow after awhile. Try to stand them on end.

"But... but how do I do this & not have the lumber flop over on me?" you ask...

You can toe nail, one on each side of the board (or) get tie plates.

Be sure to get your 2x stringers squared up or you'll have a mess on your hands no matter WHAT you use. Me, when I re-deck a roof, I like to stack two 2x's next to each other (i.e. add one new to the existing truss beam) so you get more actual coverage to support the deck. Same principle applies here. Plus, you have the added bonus of a nearly guaranteed stud hit when nailing or screwing it in.

Suggestion: Work dilligently on squaring up your first two 2x's & then cut out a pair of 2x's as spacers (like for tile). That way you'll be more easily squared up as you go.

VERY IMPORTANT! No matter what kind of wood product you use, there is a grain. The grain is laid 90 degree to the studs you're using. Otherwise, the decking will eventually bow in between them.

Think of it like this: when we do a roof, the plywood goes L to R (4' vertically, 8' horizontally) across the trusses.

98% Of the roofs we do have 1/2" type decking (usually 7/16" or 15/32") with the occasional 1x plank roof on an older house. If the size of an area in need of repairs is sufficient, we'll patch that in with 3/4", but 1/2" OSB is good enough to support 300 lbs. over a 10' x 10' area.

For attic decking, I like the 5/8" size because it's stiffer for walking but nowhere near as heavy as 3/4".

 

[14tokihorn]

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[ScoPro]

Since our garage ceiling was not insulated, we rolled in some R-13 between the joists (those are 2"X10"). Then bought 9 plywood sheets (5/8") to install. It all went in like a charm, but then we filled most of the area with a lot of useless crap.