Creating Attic Storage space...Insulation?

[Gore]

I want to throw down a few sheets of OSB in my attic for light storage (Christmas ****), and I currently have blown-in insulation.

Should I put the OSB right on top of it (i.e. compress the blown-in insulation as I screw down the flooring), or should I move it and use a roll-type insulation in its place?

Thanks

 

[pacecar]

My understanding is the R value is reduced when compressed, perhaps you could put supports down to raise the osb over the insulation

 

[Gore]

Ok, I was thinking over running 2x4's perpendicular to the joists. That would give 8" (7) of insulation.

Would you think it's better to stick with the 25 year old blown-in, or get some rolls?

I don't know why, but I think I am stuck on these rolls...perhaps it's just because they seem so much cleaner than blown-in.

 

[K'ledgeBldr]

Most of NorCal is zone3. And attic insulation requirements are R30 to R-60.

With the minimum being R-30, that's about 12" of depth for loose-blown or batt. So regardless of what material you use you still need to raise/support the decking/OSB at least 12" ABOVE the drywall of the ceiling. That's if you want to maintain as much R-value as possible in the attic.

But, I'm certainly not going to go into a lengthy dissertation as to how it should be done; the energy being wasted, or the lightening of your wallet. Then again, you could pick a different religion that wouldn't require "Christmas ****"!
JK!!!

 

[Gore]

Ok thanks for the heads up.

Fwiw, I could keep the religion, but I'd have to lose the wife, lol, she likes the decorations.

 

[Algoma56]

I used some 2 by 4 legs to raise a sheet of plywood above the insulation to store seasonal items. Insualtion isn't compressed

 

[PaulKTM350]

If you have 2x8 joist you can add the 2x4 over them to get just under 11" for the depth. Based on the Owens insulation charts for R30 you need 10.25" so that would just make it. The real issue is if the roof joists are made for storage or just plain, as the loading on the joists is very important. Sure small tree stuff is not a great deal of weight but as with most storage space you collect more stuff over time and the weight loading will get out of control fast.

 

[Kaizen]

I have the blown in stuff and hate it. however its just as good and cheaper then batts. I'd leave it. also I think I'd use 2x and stand on end making a frame over the existing framing. decorations are not heavy but someone up there with them could be.

 

[Gore]

If you have 2x8 joist you can add the 2x4 over them to get just under 11" for the depth. Based on the Owens insulation charts for R30 you need 10.25" so that would just make it. The real issue is if the roof joists are made for storage or just plain, as the loading on the joists is very important. Sure small tree stuff is not a great deal of weight but as with most storage space you collect more stuff over time and the weight loading will get out of control fast.

They are just plain joists, but I wouldn't be putting anything heavy up there.

Due to the design of my house, I actually don't have enough room to overstock my attic. I have vaulted ceilings in my living room and master, which only leaves about a 10x10 section for storage. It may be worth noting that this section also crosses over the framing of my hallway. So the storage area would not be in a large open, and unsupported, run of joists.

 

[TAMPAGT07]

They are just plain joists, but I wouldn't be putting anything heavy up there.

Due to the design of my house, I actually don't have enough room to overstock my attic. I have vaulted ceilings in my living room and master, which only leaves about a 10x10 section for storage. It may be worth noting that this section also crosses over the framing of my hallway. So the storage area would not be in a large open, and unsupported, run of joists.

I did something similar... I built an attic closet in the very corner of my attic... I just have 2x4's (Added several more) and put 5/8 plywood down with blown in insulation between them... It does have a pretty good amount of weight, but since it is in the very corner of the house (cement block outer walls) with a few (non-load bearing) walls directly underneath, I should be ok.. I try not to store very heavy items up there, but to be honest I should lighten the load up there..

 

[racerex]

I used some 2 by 4 legs to raise a sheet of plywood above the insulation to store seasonal items. Insualtion isn't compressed

Similar for me.

I’m using 2x3’s on top of the 2x8 collar ties, which will give me 10” ….enough for the 9-1/2” thick R-30 insulation. I’ve yet to attach the 8’ long 2x3’s to the 2x10’s. For now, I just temporarily placed them over the 2x10's. Once I align them, I’m going to attach them to the 2x10 using pan head construction screws….screwed horizontally through the plywood tabs into the 2x10. Once they’re mounted, I’m going to put down plywood….using subfloor adhesive and screws.

The loft space will only be used for light storage.

I've yet to install the spacers, so any design feedback would be much appreciated.

 

[PT Doc]

I used some 2 by 4 legs to raise a sheet of plywood above the insulation to store seasonal items. Insualtion isn't compressed

this doesn't mean that you have the appropriate our recommended amount of insulation though. how many inches do you have?

 

[Gore]

Would it be worth putting insulation between the rafters?

 

[Algoma56]

Quote:
Originally Posted by Algoma56 View Post
I used some 2 by 4 legs to raise a sheet of plywood above the insulation to store seasonal items. Insualtion isn't compressed
this doesn't mean that you have the appropriate our recommended amount of insulation though. how many inches do you have?

The legs are made of 2 by 4; they are about 12" tall. The 6" batts that we did a while ago, have plenty of clearance between the joist and the plywood. This year, I plan to raise it higher, and blow in insulation to get the ceiling insulation to local recommended values