Flooring for attic?

[raferguson]

I just bought a new/old house with a 900 sq ft garage. Yay!

I want to put a few light things in the attic above the garage. The trusses are on 24 inch centers. I am not worried about sag, but it has to support my weight, about 200 pounds. I am thinking 1/2 inch plywood. I will probably do it with 48 inch by 16 inch pieces, which will easily fit through the hatch, and screw them down. Does 1/2 inch plywood sound right?

Similarly, I want to build an elevated walkway down the center of the attic. I am thinking running two 2 by 6 on edge at 90 degrees to the trusses, and make a 16 inch or 24 inch wide walkway. I want to elevate it so I get adequate insulation under the walkway. Does that sound reasonable?

 

[kd3pc]

you have entered the twilight zone of GJ.

Your weight or multiple boxes and stuff AND your weight??? big difference.

I would try and check the trusses for a name/company or some such, as they may have been the basic model - with no live load...

others will say go for it. No big deal.

as to the walkway, that method has been used for decades, assuming the truss was designed for the added load on the bottom chord/base

 

[matt_i]

Imo 1/2 is insufficient and will feel very spongy. 3/4 is the way to go.

 

[Matt M PA]

There is also a company that makes a "tile" that fits on the trusses, and screws down. Mine have tabs that help them line up on the trusses. They go together like a puzzle and make a ventilated floor that's light and strong. I used them in my attached garage attic. I don't remember the brand..might have been something like Attic Deck.

I didn't have a big area to do....and also could not have fit sheets of plywood through the small opening in the ceiling.

 

[theoldwizard1]

I am thinking 1/2 inch plywood. I will probably do it with 48 inch by 16 inch pieces, which will easily fit through the hatch, and screw them down.

You need 2x4/2x6 blocking toe nailed/screwed in between the trusses under the seams that do not land on top of a truss. You might try roof panel sheathing clips, but these will be exposed and anything you try to slide over them will catch. If you do the blocking, the largest unsupported area would be 24x16. 1/2" plywood is adequate for LIGHT storage. 5/8 would be better, especially on the walkway.

 

[AP514]

Imo 1/2 is insufficient and will feel very spongy. 3/4 is the way to go.

+1

 

[rharman]

The tiles that Matt M. mentioned are really nice. I've looked at them for a long time but can't pull the trigger. Just too pricey.

I have a long low attic that i need to traverse very rarely (1x a year perhaps?) to get to a gable fan. When I do go up there, I swear I'm going to buy the tiles but I never do. I have several strips of ~16" wide plywood I've put up there to make it easier but it is still a GI Joe crawl. I'vre recently thought about a trolley on unistrut. - Not totally in jest.

In my garage, I put up OSB (1/2", I think) for decking for storage. It works OK since everything is 16" OC.

 

[The Cobbler]

my walkable attic I used 1/2 fir ply ripped to 24x96 to get thru the hatch . It's on 32" o/c , when I insulated up there I built up every other roof joist . each plywood seam has a 2x scab under it to tie it to the ply beside it . spongy? yes, but for the handful of times I go up there per yr, it'd fine & dandy thank you . all screwed so I can easily lift pcs if needed

 

[James-W]

It would be wise to contact the truss company and find out if the trusses were designed to have storage up there. You don't want to do something that isn't safe.

As far as having half inch plywood on the floor, I wouldn't do that. Perhaps 5/8 inch plywood would work out OK but personally, I would go 3/4 inch plywood.

 

[whisperinsam33]

I think you would regret 1/2" plywood. Old school solution would be 3/4" and possibly sistering some of the supporting trusswork.

 

[Flail]

If you want it rock solid, put down three flat runners of 2x4 at edges and middle screwed into trusses. Screw the 1/2" plywood on top of this. This way, when you stand anywhere, it will spread the weight over a couple of trusses. This will help to decrease truss movement and thus screw pops in your ceiling drywall.

 

[theoldwizard1]

my walkable attic I used 1/2 fir ply ripped to 24x96 to get thru the hatch . It's on 32" o/c , when I insulated up there I built up every other roof joist . each plywood seam has a 2x scab under it to tie it to the ply beside it .

This is the key to using thin plywood as flooring for light storage.

 

[The Cobbler]

.....I built up every other roof joist . ....

should have read, "each other ceiling joist" LOL

 

[6768rogues]

Around here standard trusses are built to have 10 lbs. per square foot of dead load with no live load and no concentrated load. They can handle temporary loads like walking on them during construction. If yours are typical, whatever you do will probably exceed the design strength of the trusses unless they were designed for a live load.