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Attic deck/storage, how to raise over 2 layers R30 insulation?

Attic deck/storage, how to raise over 2 layers R30 insulation?

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  #1  
Old 01-06-10, 12:30 AM
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Attic deck/storage, how to raise over 2 layers R30 insulation?

Hi Everyone,
I have an unfinished attic I'd like to use for storage by adding decking over the top of the insulation. Ceiling joists are 2X8, 16" on ctr.

The attic is laid out a little strangely. There are cathedral ceiling sections extending through the ceiling to the roof on one side of the peak. There's a 3 ft corridor between them, just tall enough to stand up.

The other half of the attic is open from the ridge to the eaves. It measures about 21' W X 28' L with room to stand up at the peak. The roof slants down to the eaves from there.

There are two main problems:

1. There are 2 layers of R30 fiberglass insulation, one layer between the joists and one layer on top of that, crosshatched. Ugh. Very little exposed joist, in other words. I don't want to compress or remove any insulation. How could I best install a raised deck platform over the top of this insulation?

I don't mind cutting into the second R30 layer as needed to expose joist sections for platform supports.

2. I need a new access door to the attic. Currently the only access is a 16"X36" unhinged trap door in the ceiling over the stairwell to the basement. It's WAY up there. To get to the attic now, I have to use a 12' ladder from one of the basement steps all the way up into the opening. It's pretty dangerous; at the top it's a 15' drop to the basement floor.

Other possibilities:

A new ceiling opening in the master BR closet. The ceiling measures 60X26", height is a little shy of 8'. Unfortunately the ceiling joists run perpendicular to the length of the closet! If I put an opening in there I'd have to cut at least one joist and build a box frame.

Or, a vertical door in the upper wall of one of the cathedral ceiling areas. I'd have to cut some 16" on center wall studs to make a 32" or 48" wide opening. Blank wall space is 7'W X 7' T in bathroom, 10' W X 8' T in dining area. It would open to the 3' corridor between the cathedral sections in the attic.

To recap: add platforms to attic for storage, add new attic opening, either in upstairs closet ceiling or in cathedral area upper wall.

That's about it. Sorry it took so long to describe - lots of angles, openings, measurements, and poverty to work around.

Thanks for your time,
Big Al Mintaka
 
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Old 01-06-10, 04:01 PM
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The folding collapsable staircases are easy to install if you have space for it.

Removing the top layer of insulation is the only way that I see to make room for the floor. You'll kill yourself adding 2x4s to the joists unless you really want to do all that work.
 
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Old 01-06-10, 06:25 PM
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Originally Posted by Pulpo View Post
The folding collapsable staircases are easy to install if you have space for it.

Removing the top layer of insulation is the only way that I see to make room for the floor. You'll kill yourself adding 2x4s to the joists unless you really want to do all that work.
Well, I would like to draw the line a little short of killing myself.

Any buildup of those joists would be done with power-driven screws. Trust me, I wasn't planning to exert myself much beyond hauling the stuff up there. I've had some experience building large platforms for train layouts using driven screws. What I haven't had to do was build up joists before installing a platform. That's where I'm not sure how to go about it.

When you say "adding 2X4s to the joists", how are they added? Are they added on the narrow side with cleats holding them to the joists, or with long screws driven through the width?

Or are the 2X4s laid flat with the screws driven through the middle of the thickness into the edge of the joists? That would take more than one 2X4 per joist to raise the level of the platform above that second layer of R30.

I guess a third way would be using short lengths of 2X4's as posts somehow.

As far as the collapsible staircase goes, I'd still have to build a box frame of some sort if I installed one in the closet. I don't know if that's a good idea structurally or not. Then again, joists were cut to make the openings for the cathedral areas...

Besides, I think a short ladder in a closet entry would be good enough because the reach isn't very far.

The idea of a collapsible staircase in one of those vertical doors I considered sounds interesting. I never though to look for such stairs for vertical openings, only ceiling openings.

So that's where I'm at, I guess. If I built up the joists, what would I use and how would I arrange the supports?

Thanks for the suggestion about those staircases,
Big Al Mintaka
 
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Old 01-06-10, 08:22 PM
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When I build up joists, I run the new boards, 2x4 or 2x6, on edge and perpendicular to the existing joists. Space 16" oc or 24" oc depending upon what I'm covering them with.

Not sure if this is what you are looking for, just my 2 cents.

Bud
 
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Old 01-06-10, 10:48 PM
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Originally Posted by Bud9051 View Post
When I build up joists, I run the new boards, 2x4 or 2x6, on edge and perpendicular to the existing joists. Space 16" oc or 24" oc depending upon what I'm covering them with.

Not sure if this is what you are looking for, just my 2 cents.

Bud
That's exactly what I'm looking for! Believe or not, until I read your post I never thought of placing the new boards perpendicular to the joists! I was stuck on the thought that I would place the new boards on edge along the joists, and either drive really long screws through the new board into the joists, or add cleats to the sides of both boards.

Good grief. The nice thing about the perpendicular arrangements of the new boards is that I can run them between sections of the cross-hatched R30 without having to do any cutting. Magnifique!

I'm already busy making bad guesses about how to attach the new boards to the joists. Would those metal construction braces used to attach studs to joists be the best way? In my case I would still use screws instead of nails, but I'd drive the screws through the holes in the braces.

This is actually inspiring! Up to a point, that is. Now I'm wondering if I'm a dullard and/or have brain damage that kept me from thinking about the perpendicular layout.

I know I've been saying that I'll try to make things easy for myself by power-driving screws instead of hammering nails, but there's a sleeper here I haven't even mentioned: I don't get along well with fiberglass insulation. I have a decent chemical mask for spray painting that will take care of the breathing part. However no amount of protection on my skin is going to prevent the hives.

I'm hoping that if I build the platform piecemeal and work off the already raised section, I can minimize contact with the insulation. I should probably open a new thread about how to endure the stuff.

Thanks again for that tip!
Big Al Mintaka
 
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Old 01-07-10, 06:14 AM
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I'm reminded of the joke where the guy gets a flat tire just outside a fence to a mental institution. As he is changing the tire he notices one of the residents inside the fence watching. As he slides the new wheel onto the studs, he looks around and the lugs are nowhere to be found. He looks and looks to no avail. As he is standing next to the car totally perplexed, the resident speaks up and says, why don't you take one lug from each or the other wheels and that should get you to a garage. Enlightened by the suggestion he does exactly that, but before leaving he goes over to the inmate and says, that was a very good solution, so why are you in there? The residents replies, look, I may be crazy, but I'm not stupid.

We all lose track of our lug nuts once in a while .

Enough drift, but I've been there.
There are hurricane brackets that make a 90 degree bend for exactly what you want. Once the deck is attached on top the walkway will be very stable. Where you have seams on the plywood/osb, you can install a support or strip of 3/4 on the flat to catch both edges.

It's the right time of year to be in the attic and need to cover up, so be generous with long sleeves, gloves and tape all closures. Old fiberglass is much worse than new, in fact some of the new comes enclosed in a breathable membrane. Other materials might be worth considering since you live below.

Enjoy and make sure you don't put more weight up there than the structure can hold.

Bud
 
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Old 01-07-10, 07:46 AM
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That is a great idea. It's so much easier than trying to do a balancing act on each joist.
 
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