My latest project is to relocate a small scuttle hatch from a bedroom to the hallway

allthumbsdiy

My latest project is to relocate a small scuttle hatch from a bedroom to the hallway and install a pull down attic stairs. Ultimately, I would like to store seasonal stuff (i.e. Christmas trees, etc.).

BACKGROUND
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-1960's colonial
-ceiling joists are 2x6" with 16 O.C. framing
-roof rafters are 2x6" with 16 O.C with collar ties on every other rafters
-ceiling joists span approx. 10' 7" on both sides of the bedroom with the hallway being approx. 2' 8" wide

PLAN
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In order to create a large enough opening for a pull down attic stairs, I need to remove 2 ceiling joists.

Unfortunately, due to strong backs, pipes and wiring, I am unable to install full-length 2x6 to sister existing ceiling joists.

Can you guys take a look at my plans A & B (at the bottom) and let me know if it will be structurally sound?

I also plan on installing 1/2" ply near the weight bearing wall to store some light, seasonal stuff like Christmas tree, lights, etc.

jcarlilesiu

Pretty decent plans.

A couple of comments. Why all the additional blocking?

On the bottom (drawing wise) of the scuttle, you have a sistered 2X6 that barely engages the load bearing wall due to the offset of the existing joist serving the other side of the construction. This is less desirable than allowing the sistered joist to bear completely on the load bearing wall.

Since you aren't taking the sistered joists all the way back to the beginning of the span, the wall adjacent to the load bearing wall will start to get loaded. Are the existing joists you are sistering resting on the non-load bearing wall?

Even though the joists span over this wall, there is some loading there. Technically, as it is built now, you can remove the wall without issue if the joists were appropriately sized, but sistering new joists and terminating at this wall will not allow the future removal of that wall. Essentially, you are changing it to load bearing. Only slightly, but you should be aware of that.

On the last drawing at the bearing wall, you show a triple 2x box joist at the scuttle opening. The joists terminating from the right will still be bearing on the load bearing wall. There will be no lateral transfer of load to the joists adjacent. This may be over designed.

allthumbsdiy

Thanks for the comment and here are my responses:

1. BLOCKING - I read that blocking helps to spread the load between joists? since I plan on storing some stuff on my puny 2x6 ceiling joists, I figured I would install blocking whenever possible.

2. NON-LOAD BEARING WALL - This wall serves as room walls for 2 bedrooms and a bathroom so I will *not* be changing them at all, now or in the future. As far as I can tell, this wall does *not* rest on any type of walls below (it's an open floor living room below).

3. SISTERED JOISTS (scuttle hatch) - All existing ceiling joists from the bedroom #2 side span over the non-load bearing wall but they are not tacked in. As stated in #1, this non-load bearing wall rests on 2x6" joists in my living room with no walls at all, I would like to minimize any loading.

Taking what you said into consideration, I made some changes to my last proposal. What do you think about latest version?

Specifically, I moved the bottom sistered joist K (from my previous drawing) to sit next to a joist coming from bedroom #1 (I). I then drew in (J) which will tie in both joists from bedroom #2 and #1 together. I extended the same concept to the top portion (A & B).

My thought here was to increase the vertical and horizontal rigidity from shortened joists (D & E) by transferring loads to ceiling joists F, G, H & I and also minimize any loading to my non-load bearing wall since it simply rests on 2x6" ceiling joist in my living room below without any stud support.

Ceiling joists A & J will extend at least 4 feet over the load-bearing wall secured by 3/4" ATSM A-325 structural bolts, washers and nuts as well as staggered 16d framing nails.

4. TRIPLED HEADER - based on your comment, I guess I will not be needing this so I eliminated it.

Looking forward to feedback from everyone.

PS. I drew these diagrams on Adobe Fireworks CS5, not from a 3D CAD software.

jcarlilesiu

I think you have done your homework well.

Good luck with your project.

hand drive

consider also putting other floor members on top of your 2x6 joists around your new door to extend the attic decking height upward and allow room for insulation. now is the time to do that as you are planning your design and you will have adequate insulation along with your new door 4 to 8 feet either side of the door is average sizes for attic storage space...

Gary in WA

If the solid blocking is in-line, rather than spaced apart, you can expect a 15% reduction in deflection; http://www.ewpa.com/Archive/2004/jun/Paper_278.pdf

As the header joist farthest from the closet bearing wall is within 3' you could single trimmer and header it all and meet minimum code, though anything more will be stronger; http://publicecodes.cyberregs.com/ic...002_par031.htm

Gary

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Msradell

Are you sure that hole is big enough for a pull down stairway? It doesn't look long enough compared to most of the ones I've seen.

allthumbsdiy

Thanks everyone for your feedback.

As far as adding a deck to allow for thicker insulation, I think will need to be careful here as I do not want to further increase my static load with extra lumber due to 2x6 limits.

Regarding the size opening, you are right, this opening is less than the usual 50"+. I did not want to install a full sized attic stairs because:

1. I really, really did not want to cut a third ceiling joist because I am unable to install a full length sistered joist;

2. I wanted to discourage future owners (whenever that may be) from lugging large and heavy items to the attic

I plan on installing Werner's compact sliding ladder (not Televator) which is rated for 250 lbs.

I will keep you up-to-date (although I need to work on my HVAC project first) during next 2 weeks.