Attic Ladder In Garage

[FarmerPete]

So, I was thinking that it might be a good idea to put in some flooring in my garage's attic. It's not too big, but I think I could store a good amount up there. The problem I have is that the rafters/joists are 16" OC. The narrowest option I've seen needs 18", and 22" is much more common. So I know I could sister up the joists on either side, put in a cross brace on each end of the opening, and I should be fine.

When researching doing this, I see a lot of people saying not to mess with Trusses without an engineers sign off. I'm not sure that applies to me, since the roof is not supported by these joists, except at the walls. Should I be concerned, or can I go for it? Also, if I do go for it, is it necessary to match the joists with an identical length beam? My garage is over 20' long, and I don't have a way to transport lumber that long. I'm planning on using construction adhesive and nailing 3 16d nails every 16 inches. The joists appear to be 2x6s.

 

[pattenp]

Fist thing is you need to clarify if you have truss or stick built rafter and joist. Truss should not be cut but rafter and joist construction can be modified.

 

[captain14]

Pictures also help with your description.

 

[FarmerPete]

Pictures also help with your description.

This is the only picture I've got on me. Hopefully it helps. There's a little over two feet of clearance between the top of the joists and the bottom of the roof supports. I figured that I could get some decent cold storage for things and free up some basement space.

 

[porschedude996TT]

That is stick built. You should be able to sister up joists. Funny I have never seen a ridge beam that is 1 inch thick...

 

[FarmerPete]

That is stick built. You should be able to sister up joists. Funny I have never seen a ridge beam that is 1 inch thick...

It was built in the 60's. Does the sister need to be a single beam, or can it be 2 or 3 shorter beams?

 

[Falcon67]

That is stick built. You should be able to sister up joists. Funny I have never seen a ridge beam that is 1 inch thick...

What he said - the old building at our ex-house used a 1x4 ridge "beam". That building also was 16' wide with 2x6 joists on 48" centers. So there, compare that to a code LOL.

I'd run a joist at your ladder width - say 22" or 24" from the other joist you'll use, then just cut the one in between and double plate across the cut ends. That ought to be more than enough for 16" OC type joists.

 

[pattenp]

What is the clear span of the ceiling joist? And can you confirm they are 2X6? From what I'm seeing in the picture I don't believe you can store much of anything because the ceiling is only built to support a drywall ceiling at best, but not for attic storage.

 

[pattenp]

This is a bad idea. The truss is designed to spread load from the top to bottom out to the walls. The bottom cord is in tension and you will compromise the strength of the truss by cutting the cord. Usually when spacing is increased for stairs that need more than 24" there are two trusses placed together either side of the opening with purlins spaced in between. Doing what you're thinking may never cause an actual problem but when you decide to sell the property a home inspection may catch it which could cause you some grief.

Edit: ???Oh well... green2kgt post just disappeared.

my trusses are 24" apart on center but I do not want to use the pull down ladder. I will actually be building an attic ladder against the west wall of my garage where the 1st truss is 18" in from the wall and I want the opening to be 4' x 34" so ill be cutting my truss. I will be building a ladder that is bolted to the wall and runs up to the attic opening. The truss has a break in it about 1.5' off center and I will be removing the bracket holding the 2 boards at that break and butting a couple of 2x4's up to and I will do the same at the other end of the opening where ill have to cut the truss. Below is a picture of the area I will be putting it so you can hopefully get a better idea. you can see the bracket ill be removing, its the bracket next to the garage door mount closest to the wall.

 

[FarmerPete]

Measuring them from the ground, I can confirm that they are at least 5". I'd have to get up a little higher to make sure. The clear span is 20-22'.

 

[green2kgt]

This is a bad idea. The truss is designed to spread load from the top to bottom out to the walls. The bottom cord is in tension and you will compromise the strength of the truss by cutting the cord. Usually when spacing is increased for stairs that need more than 24" there are two trusses placed together either side of the opening with purlins spaced in between. Doing what you're thinking may never cause an actual problem but when you decide to sell the property a home inspection may catch it which could cause you some grief.

thanks for the info.

 

[OccupantRJ]

I just gave away a new attic stair to a friend. I had saved it for years to use in my new shop, but approaching 61 years of age, I decided to go the safety route and not store anything above in the attic, so I would not be tempted to be climbing with things in my hands. I am in good health, but all it takes is one wrong move, and concrete is hard. I built a 20x18 storage barn out of metal, and after using it for a couple of years, I am glad I went this route. I now realize how much effort I expended in my previous shop by placing and retreiving things into and from the attic. Now I can simply walk in and get what I need. I am soon going to be installing metal ceiling in my shop and will have a simple access hatch for service needs for the vent fans and electrical.

 

[ddawg16]

I will never use one of those fold down ladders again....I have one to the attic of my house...I wish I had used the telescoping type.

Anyway....back on topic....your garage looks a lot like mine did....those are more like rafter ties....they keep your walls from pushing out. That one 1x6 board running across the top was most likely put there during construction to hold everything in place. If you put sheathing up there....you don't need it....the sheathing will perform the same function.

With that said.....I must first give a disclaimer....

"Those rafter ties are not designed to hold weight"

End disclaimer....

I did the same thing in my garage.

What size are your joists? They look to be 2x6's...if so...that span is a bit too much to really put any weight up there.

Personally....I would sister 2x8's across there. And yes, you can get 20' long 2x8's.

Where you want the ladder...take out one section and do the appropriate blocking....

I would then use 1/2" CDX plywood. It's a bit lighter than OSB and will tolerate deflection better.

I would not glue....just use #8 drywall screws. This allows you to remove it if you want....and will be just as strong as nails and glue...if not stronger.

 

[FarmerPete]

What size are your joists? They look to be 2x6's...if so...that span is a bit too much to really put any weight up there.

I don't want to do anything unsafe. Any ideas for a good way to get this to be a bit safer? I don't mind sistering up a couple more joists, but again, I don't have a good way to get a 20' beam home. I'm thinking that if I was to sister up the joists, maybe I'd do every other one. I don't know if I have the clearance to put in a cross beam.

It's only 2 feet of clearance in the attic area, so obviously we wont be walking up there. I just want a place to keep some seasonal stuff (Christmas stuff, boxes of clothes, etc). I figured I'd put in 3/4" tongue and grove plywood for the floor. I'm not planning on covering the entire area, just the center of the garage.

 

[Falcon67]

I don't see "truss" anywhere there, just 60's style construction.

I had 400 lbs of **** in the attic of the garage I spoke of, because I had to unload all of it when we moved. 8 16' 2x6s, stacks of various length 2x4, steel tables (2), pipe, exhaust pipe, misc.

The shop used 2x6 joists and was 20x24 with two storage sections made from 4x8 OSB. Two on one end, two on the other. There was over 1000 lbs of stuff up there - carbs, driveshafts, cranks, axles, pipe, etc, etc. Took us two days to get it all down and it covered 3/4 of the 20x24 floor area. The joists sagged about one inch from that load over the span of 12 years. Did I mention the chain fall used to pull engines with?

For what you are going to do, a sheet of 7/16 OSB or two down the middle will be plenty. Just don't store cylinder heads or an engine block up there. The sheets - as above - will spread any load across several joists.

 

[bczygan]

Not a very usable space.
The stair will only allow access to one small area.
Heavier things need to be closer to the walls and lighter things in the middle of the span.
You will get better support at the back wall where the last ceiling joist might be secured to the end wall.
3/4" is too heavy. Use 1/2" plywood as advised above.
You can't jockey long things into that space. Best to use it for light storage of things not used ofter like Christmas decorations.
If used for storage, you can't insulate.
The 1" by is a ridge board. Used solely to line up the rafters. It supports nothing.
I see no rafter ties. You could add rigidity by adding them at every pair of rafters.
Also a strongback (Google it) or two would help with that span.

Frankly, I would just throw a few pieces of ply up there and not even fasten them down.
Instead of a stair I would just use the right sized a-frame ladder to access the space anywhere I needed. Leave much of it open for access.

 

[green2kgt]

Edit: ???Oh well... green2kgt post just disappeared.

Yah I took it down bc it kinda took away from the OP's post. Thanks for the info.
Ill prolly just do the pull down stairs since ill barely be using it and its for nothing with weight to it. Ill be he heaviest thing up there, lol.

 

[48windsor]

well here is my two cents . I have an attic space above my garage that I lined with quarter in . plywood and drywall screwed to rafters. Works great . and have a bunch of stuff up there . the only thing I did do though is reinforce the connectors with a bolt and strap idea. I put an attic ladder up to it and some fluorescent lighting up there . Awesome

 

[Kevin C]

That is stick built. You should be able to sister up joists. Funny I have never seen a ridge beam that is 1 inch thick...

In this case, the piece of wood in the ridge is only used to make it easy to align the joists when framing. Non structural, according to my framing book at that point its called a ridge board.

I have seen some older homes that just had the joists nailed face to face and skipped using a board at all. I have never seen a 1 inch thick board up there either, its always been beam, 2 x X or nothing.

 

[Lippyp]

My garage has the same ridge board system, it just makes it easier to build the roof and doesn't do anything else (until it rots like mine and then it makes everything sag!)

 

[FarmerPete]

If used for storage, you can't insulate.

I had though of maybe using some insulation between the rafters. Is that a bad idea? I intended on insulating the walls, and I figured I should do something to insulate the roof. I'm not planning on installing any real heating or cooling in the space. I thought that adding some insulation would help stabilize the temperature a bit, and it would make it not 100% futile to try using a space heater in the garage on occasion.