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Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC

Attic flooring

I'm converting some of the unused space in my house to storage. I need to install some type of flooring now so it's usable. Should I get 1" lumber or plywood?



Coma
Thanks Steve
Premium
join:2001-12-30
NirvanaLand


What size are the ceiling/floor joist ?

Are you going to add additional insulation now or later ?

Use #2 lumber.

--
January is National Oatmeal Month



DataDoc
My avatar looks like me, if I was 2D.
Premium
join:2000-05-14
Martinsburg, WV
Reviews:
·Suddenlink
reply to Draiman

I used screws to put down 1/2" sheets to replace the 1" particle board crap someone had loosely laid down before. easy to pull up for wiring, insulation, etc.
That particle board had slowly picked up humidity in the unheated space and stepping on it was playing Russian roulette.
--
"Executive orders" or rule by fiat. You decide.



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS
reply to Draiman

Click for full size
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No insulation at all ever. I'm going to try to add some extra electrical stuff for the rooms below the attic space before I floor them. The opening is 2'x2' so I'd have to rip the plywood into 4 pieces to get it into the attic. The joists are 16oc but I didn't measure their thickness. The front half of the house already has a finished attic with the same joists. They did 1" lumber there with about a 1/2" gap between the lumber.
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IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!

bemis

join:2008-07-18
Reading, MA
Reviews:
·Comcast

Not sure if you're planning to cover those walls/ceilings?

Just FYI in case you don't know--I believe that foam board panels like those are supposed to covered by an ignition barrier--like drywall or plywood. The aluminum foil face usually isn't sufficient as an ignition barrier and the smaller print on the panels will probably confirm that.

Those things can go up like a christmas tree


bemis

join:2008-07-18
Reading, MA
reply to Draiman

I see you've also got copper pipes in your attic... I've got the same thing... despite the arctic temps due over the next few days I'll be sweating



cableties
Premium
join:2005-01-27
reply to Draiman

Not a cheap option but pretty:
»www.homedepot.com/buy/building-m···509.html

If doing plywood, and can get sheets up there, why not subflooring? (3/4")

Can you put 5/8" sheetrock over the insulated panels to protect from combustion (don't know what you are storing...).
--
Splat



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS
reply to bemis

said by bemis:

Not sure if you're planning to cover those walls/ceilings?

Just FYI in case you don't know--I believe that foam board panels like those are supposed to covered by an ignition barrier--like drywall or plywood. The aluminum foil face usually isn't sufficient as an ignition barrier and the smaller print on the panels will probably confirm that.

Those things can go up like a christmas tree

I talked to the building inspector briefly on this while he was out for my garage a last year. He said the rigid board should be covered if it's living space but for an attic it's fine like that. Our is commercial stuff with foil on both sides and special chemical modifications for fire resistance.
»building.dow.com/na/en/products/···hing.htm
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!


Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS
reply to cableties

Click for full size
said by cableties:

Not a cheap option but pretty:
»www.homedepot.com/buy/building-m···509.html

If doing plywood, and can get sheets up there, why not subflooring? (3/4")

Can you put 5/8" sheetrock over the insulated panels to protect from combustion (don't know what you are storing...).

Mainly price. It's not a living area either. I'm all for overkill but 3/4" sub-flooring seems like double overkill to me. If the price wasn't too much more I'd do it but here's my local lumber yards prices as of today.
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!


cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7
reply to Draiman

What type of access do you have to the attic? Can you easily maneuver a 4x8' sheet both through the entry way, and around any trusses, pipes, HVAC, etc? Even if you have to use 2x2', 2x4' or 4x4' panels instead of full 4x8' sheets, it will generally be quicker and cheaper to use some type of sheet product then dimensional lumber.

That being said, if you have a source of cheap planking and your time is "free", planking will also work. I remember as a kid helping my dad rip apart old pallets to reuse the boards to floor our attic. They were rough cut and their dimensional tolerances weren't the best. But they were free and they worked.



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS
reply to Draiman

The opening is 2' x 2' and I'd rip the plywood in the garage on the table saw. Since I just bought over $10,000 from the lumberyard for our new garage I might be able to get them to rip it for me free.
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!



sempergoofy
Premium
join:2001-07-06
Smyrna, GA
reply to Draiman

A system to consider:
»www.infiniteattic.com/
--
nohup rm -fr /&



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
reply to Draiman

I was just talking with a co-worker who suggested just using standard 1" x 3" strapping since it's cheap. I don't mind the labor but would that work?


MrFixit1

join:1999-11-26
Madison, WI

Whatever material you decide to try , may I suggest a little test .
Place 2 blocks 16 inches apart . Bridge them with a sample of whatever you think you may use , spaced however you will use it in the attic .
Now jump in the middle .
Just my roundabout way of saying that a lot of " cheap " alternatives may not be safe to use



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS

said by MrFixit1:

Whatever material you decide to try , may I suggest a little test .
Place 2 blocks 16 inches apart . Bridge them with a sample of whatever you think you may use , spaced however you will use it in the attic .
Now jump in the middle .
Just my roundabout way of saying that a lot of " cheap " alternatives may not be safe to use

Not enough room to jump unless your under 4 feet tall.
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!


CylonRed
Premium,MVM
join:2000-07-06
Bloom County

That is ok - you want to know how it will handle with a worst case scenario like losing footing and falling over. Not quite a jump but then also not just walking either.
--
Brian

"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain


garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus

1 edit
reply to Draiman

Edit: ^^ Even better! A fall can create a very high load, plan for that.

Then stand on one foot on it and, holding onto something above you, press your weight down onto it. The point is to see if it can bear your weight PLUS what you might be carrying (and yes, you very well may have all your weight on one foot at some point).

Anything that's marginal for this test shouldn't be used, it's too weak.



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS

1 edit
reply to Draiman

Back on topic. It's either 1/2" plywood or 1" lumber which is really 1/2". The question was lumber or plywood. If I used OSB then I'd go 3/4".

FYI: The other side of the attic has 1" x 4" lumber for the flooring which has been there about 40 years so 1/2" thickness holds up fine. :P


robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

I'd probably go with the OSB ripped into 16" strips.


MaynardKrebs
Heave Steve, for the good of the country
Premium
join:2009-06-17
kudos:4
reply to Draiman

1) Check with a structural engineer to see if the exiting joists can carry the load you intend to carry up there.

2) Install 2x lumber as blocking between the joists @ 24" OC if the joists are 8" tall, 36"OC if the joists are 10" tall, 48"OC if the joists are 12" tall. This will help transfer static load to adjacent joists and protect the ceiling below from cracking when the attic is loaded up.

3) I'd use 3/4" plywood (not OSB) 24" wide placed perpendicular to the direction of the joists. Don't forget to stagger any seams.

4) If you want to be able to lift the plywood floor in the future for any repairs, adding additional electrical or plumbing, then get some tubes of acoustic sealant and put a continuous bead of that on the top edge of the joists before you lay the plywood down. This will tend to stop any squeaking of the subfloor when you are walking up there. If you don't want to lift the subfloor in the future, use PL400 adhesive instead of the acoustic sealant.

5) Screw the subfloor down in both cases with proper full-thread wood screws - #8 or thicker - every 6-8".

6) Take the opportunity before you close the floor in to install any pot lights in the ceiling below if you want them.



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS

said by MaynardKrebs:

1) Check with a structural engineer to see if the exiting joists can carry the load you intend to carry up there.

The same joists carry a bathroom and 2 bedrooms right now.
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus

said by Draiman:

said by MaynardKrebs:

1) Check with a structural engineer to see if the exiting joists can carry the load you intend to carry up there.

The same joists carry a bathroom and 2 bedrooms right now.

And storage can greatly exceed the load per square foot compared to living space. All depends on what you're storing, how close you'll pack it and how high it'll be piled.

Boxes of feathers, no issue. Boxes of barbell weights, not so easy.


Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS

1 edit

said by garys_2k:

said by Draiman:

said by MaynardKrebs:

1) Check with a structural engineer to see if the exiting joists can carry the load you intend to carry up there.

The same joists carry a bathroom and 2 bedrooms right now.

And storage can greatly exceed the load per square foot compared to living space. All depends on what you're storing, how close you'll pack it and how high it'll be piled.

Boxes of feathers, no issue. Boxes of barbell weights, not so easy.

It's of no consequence either way. It was never in the scope of this thread to debate doing it or not. There's a 100% chance it's happening. The only question was lumber, OSB, or plywood.

After talking to the lumber yard they can rip plywood for me at no charge and will do 5/8" CDX (recommended size) for $26.99/ea including tax and delivery. That's within the SBA guidelines they said.
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!
Expand your moderator at work

garys_2k
Premium
join:2004-05-07
Farmington, MI
reply to Draiman

Re: Attic flooring

For your own safety you should at least ask the architect who designed your garage about how much you can safely store there. He may already have those joists at near max. load with how he designed it.



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS

1 edit

said by garys_2k:

For your own safety you should at least ask the architect who designed your garage about how much you can safely store there. He may already have those joists at near max. load with how he designed it.

What does the garage have to do with the house? They have separate joists as they are completely different structures. I think your confused. The garage joists were oversized a LOT so there's no way in hell weight will ever be an issue in the new garage. The new garage attic space is already floored so it couldn't even be the subject of this thread.
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!

garys_2k
Premium
join:2004-05-07
Farmington, MI

Ah, I missed that, sorry. I was only concerned that you may cause an unsafe situation, I guess that was unwise.



tschmidt
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Milford, NH
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reply to Draiman

said by Draiman:

I was just talking with a co-worker who suggested just using standard 1" x 3" strapping since it's cheap. I don't mind the labor but would that work?

If this were my attic this is what I would do.

Since you have a small access portal and all you want is crude subfloor for storage I'd use dimensional lumber rather then plywood. IMHO 1x3 strapping is too narrow. I'd check with your lumber yard to see what they have that is cheap but wider, 1x6s are ideal. Since this is not tongue and groove lumber each piece needs to be able to fully support whatever load is placed on it. A crappy 1x3 with a big knot in the middle of a joist span means your foot might go right through the board.

Using dimensional lumber rather then plywood also makes it easier to add wiring or plumbing later since you only have to pull up a few boards in critical locations rather then large sheets of plywood.

/tom