Forums | Home Repair | Home Improvement | Painting | Interior Decorating | Remodeling | Landscaping


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Carpentry

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 10-21-2009, 11:45 AM   #1
Newbie
 
Join Date: Oct 2009
Location: San Antonio
Posts: 6
Share |
Default

Can someone explain this Attic Space for me?!?!


Hi Everyone. I would like to finish this space in my attic. It already has walk up stairs. I have read and read and googled and googled and still don't understand some basics here.
Referring to the pictures: There is a ridge board that extends the length of the roof, 30 ft.
There are 2x6 joists (item 2) that are spaced every 24 inches on center. There are 2x4 crossties (item 1) spanning every other joist.
There are walls (item3) with a top ridge piece and vertical supports at every other joist the length of the room (30ft).
There are 3 center posts, (item 4). 1 is not pictured, evenly spaced along the center of the room.
There are diagonal supports (item5) along the side walls on each wall.
The room is 30 feet long and 21 feet wide. The side walls pictured are 8 ft tall. The space between the side walls is 11 feet. The crossties pictured are 11 ft from the floor. The floor is 16inch i-beams spaced 12 inches apart.
I would like to remove the center posts, push out the walls by 12 inches on each side, and install a 9foot ceiling the length of the room.
Is this feasible?
Can I remove the center posts?
Can I move the side walls back 12 inches?
Can I remove the diagonal braces (item 5) or shorten them to stay behind the walls?
Thank you very much for any insight you can provide.


Last edited by TX Recon; 10-25-2009 at 10:03 PM.
TX Recon is offline   Reply With Quote
Old 10-21-2009, 12:02 PM   #2
Member
 
Join Date: Oct 2009
Posts: 672
Default

Can someone explain this Attic Space for me?!?!


That is a hodger podge of supports and framing. It is impossible to give an answer at this point.
1) How old is the house
2) What are the depth of the TJI ceiling joist this structure is bearing on?
3) Are the pony walls bearing upon walls underneath.

You have a mess, and anyone who would give you a specific answer to your questions based on this photo is either guessing, or a fool.

But add enough wood, and open up enough walls on the storey(s) below, and much is possible


Last edited by Anti-wingnut; 10-21-2009 at 12:05 PM.
Anti-wingnut is offline   Reply With Quote
Old 10-21-2009, 12:14 PM   #3
Newbie
 
Join Date: Oct 2009
Location: San Antonio
Posts: 6
Default

Can someone explain this Attic Space for me?!?!


1, it's 8 years old
2, the joists are 16 inches deep
3, I don't even know what pony walls are. Item 3 in the pictures are not bearing on walls underneath. The outer walls at the end of the joists are on top of load bearing walls.
A mess? Really? Fools responding? Really?
I was present for the framing inspection and I don't remember any problems or the inspector saying it was a mess. And I've been reading this forum for a long time and don't remember anyone being called a fool for making possible suggestions or tossing around ideas.
Anyway, thanks for looking at it. If anyone else would like to try to explain it to me I'd really appreciate it. Thanks...
TX Recon is offline   Reply With Quote
Old 10-21-2009, 12:17 PM   #4
Member
 
Join Date: Oct 2009
Posts: 672
Default

Can someone explain this Attic Space for me?!?!


Quote:
Originally Posted by TX Recon View Post
Can I remove the center posts?
Can I move the side walls back 12 inches?
Can I remove the diagonal braces (item 5) or shorten them to stay behind the walls?
Yes to all.

Happy now
Anti-wingnut is offline   Reply With Quote
Old 10-21-2009, 12:21 PM   #5
Member
 
Join Date: Mar 2009
Posts: 780
Default

Can someone explain this Attic Space for me?!?!


I would suggest you hire a structural engineer. It would be cheaper than having the roof collapse.
hayewe farm is offline   Reply With Quote
Old 10-21-2009, 12:31 PM   #6
Old School
 
Willie T's Avatar
 
Join Date: Jan 2009
Location: St. Petersburg, FL Minds of moderate caliber ordinarily condemn everything which is beyond them.
Posts: 3,634
Default

Can someone explain this Attic Space for me?!?!


Since you were there for the framing inspection, it should be feasible for you to contact both the framer and the inspector to ask some "How come?" questions.
__________________
"True eloquence consists in saying all that is necessary, and only that which is."
François Duc de La Rochefoucauld
Willie T
Willie T is offline   Reply With Quote
Old 10-21-2009, 12:34 PM   #7
Member
 
ArmchairDIY's Avatar
 
Join Date: Oct 2009
Location: Wisconsin
Posts: 116
Default

Can someone explain this Attic Space for me?!?!


There are many things about the way it is framed that have me slightly puzzled. But in general it seems to be a little on the lite side. But we have snow to deal with around here so that may be why it seems a little flimsy to me.

Is it possible?
It could be be.
Is it possible to answer from looking at the photos?
Not in my opinion.
I do think you need to hire an engineer to be safe.
Don't forget about insulation and ventilation issues too.
Plan well now and things will go much smoother latter.
ArmchairDIY is offline   Reply With Quote
Old 10-21-2009, 01:16 PM   #8
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Default

Can someone explain this Attic Space for me?!?!


Do you have a picture of the roof from the outside ?
Scuba_Dave is offline   Reply With Quote
Old 10-21-2009, 01:46 PM   #9
Newbie
 
Join Date: Oct 2009
Location: San Antonio
Posts: 6
Default

Can someone explain this Attic Space for me?!?!


Thanks

Last edited by TX Recon; 10-25-2009 at 10:04 PM.
TX Recon is offline   Reply With Quote
Old 10-21-2009, 02:41 PM   #10
Member
 
Join Date: Oct 2009
Posts: 672
Default

Can someone explain this Attic Space for me?!?!


OK, I'll explain this nicely. Your ridge beam is not a structural element, it is only there to hold up the rafters. The rafters are probably undersized, and the collar ties (item 1) are too high to be effective.

Items 4 and 5 are probably remnants of the construction process. Item 3 (pony wall) is probably a poorly thought out attempt to stiffen a undersized roof system.

At first glance, what a competent framer could suggest is supporting the ridge with a structural ridge. This could be a Glu-Lam, steel, or a number of other materials. Where this is supported at the gable ends, the newly constructed point load will have to be properly supported.

The rafters could be sistered to deeper dimensional lumber, allowing all pony walls, supports, and intervening posts to be removed.

But the answer must be derived at by a competent person looking at your attic , or at the framing plans. No one can tell you exactly what to do looking at these photographs. This system needs to be correctly designed. An engineer could do this, as well as a contractor or architect. A contractor would probably be unwilling to do only structural designing for you, if the construction was not in his scope.

It is unfortunate that you took umbrage at my characterization of the posts, ponies, and bracing as a hodge podge, but that is truly what it appears to be. If anyone tells you otherwise, I would be shocked. But you project should be doable. You could even do it with a good enough set of plans
Anti-wingnut is offline   Reply With Quote
Old 10-21-2009, 04:37 PM   #11
Member
 
Join Date: Jul 2007
Posts: 1,467
Default

Can someone explain this Attic Space for me?!?!


This is an interesting one. As AntiWingnut says the small ridge board you have would normally not be structural - otherwise a larger beam would have been used.

But I believe in this case it still does function to some degree structurally and that is why the center posts were used so that the undersized "beam" is adequate. Rafters push out on the walls as well as down. Most houses have ceiling joists to prevent the walls from being pushed out but a structual ridge beam can also serve this purpose. Since there are no joists across your top plates and the collar ties are too high to prevent the walls from splaying out then it appears that two things were incorporated to prevent the walls from being pushed out. First the center posts to cause the rifge board to function more like a structural beam. Second is the diagonal braces (#5).

If you remove the diagonal braces and center posts without taking other steps the walls will be pushed outward eventually. Your proposed ceiling joists at 9' may or may not be able to replace the posts and diagonals. You definitely want an engineer to run numbers on this and design something that will work.

Note that I'm not saying your current attic is done wrong, it's just an unusual way to deal with the forces involved but might very well be adequately designed if you don't remove anything.

Update: I just noticed that the centerpost and pony wall posts all have T members nailed to them. This suggests that they are indeed carrying significant load. The T members prevent the post from buckling (bending/breaking out to the side) under load. You definitely don't want to wing it here. Get an engineer involved. You'll want him to check out the floor too to make sure it's strong enough.

Last edited by jogr; 10-21-2009 at 04:44 PM.
jogr is offline   Reply With Quote
Old 10-21-2009, 04:42 PM   #12
Member
 
Join Date: Oct 2009
Posts: 672
Default

Can someone explain this Attic Space for me?!?!


Quote:
Originally Posted by jogr View Post

Note that I'm not saying your current attic is done wrong, it's just an unusual way to deal with the forces involved but might very well be adequately designed if you don't remove anything.
His current attic has been done wrong. If there is any question, I can post this on ContractorTalk, and they will rip the original framer to peices. Quality work is not done this way, and work correctly designed is not designed this way.
Anti-wingnut is offline   Reply With Quote
Old 10-21-2009, 05:05 PM   #13
Civil Engineer
 
Join Date: Mar 2009
Location: Boston
Posts: 3,981
Default

Can someone explain this Attic Space for me?!?!


I spent a year after Hurricanes Katrina and Rita inspecting damaged homes in the Gulf Coast area, and frankly the framing on this house is much better than most of what I looked at (and I looked at houses that were intact as well as some that were completely gone down to the foundation). Framing practice on the Gulf Coast, including Texas, is simply different than it is in northern areas where snow load is a serious problem.

That said, I believe the previous posts were on the money in analyzing the reason for the combination of framing techniques. The rafters are undersized (previously noted), but are partially supported by the pony wall and columns. This means that the ridge board is acting somewhere between a ridge beam (fully supporting structural element) and a ridge board (no structural value), as previously noted. It also means that the columns need to be adequately supported, and without a detailed inspection it is impossible if the columns are adequately sized and supported.

In conventional framing, a pony wall would act in lieu of the collar ties, however you have both, which creates a more complex structure to analyze than normal. However, as previously noted, the collar ties are up quite high, and likely do not contribute much resistance to lateral spreading of the rafters.

Assuming the columns are properly supported, you certainly could install a ridge beam, however you may need to install larger columns (check for buckling), or if you want to get rid of the columns completely, you would need to frame in an adequate wall on either end to support the ridge beam. The ridge beam and associated framing is normally designed by an engineer or architect. If you go with the ridge beam, your rafters would only be supporting dead load roof weight plus wind uplift, and they MAY be adequately sized (this would be checked by the designer of the ridge beam). If you go with a ridge beam, you could get rid of the collar ties and the pony walls, and open the entire space up. The other advantage of the ridge beam is that you would not have to worry about lateral spreading of the rafters.

At 31 feet, the ridge beam would require either steel, or my preference would be a glue laminated beam or LVL. Other things to check would be the presence of hurricane clips on the rafters, and the design of the floor in the attic. Since it would now be living space, the dead and live load requirements would increase, and the existing floor joists (or whatever you have under that floor) would probably need to be replaced.

In summary, nothing wrong with the framing job as I see it, a little unusual, but seems to be adequate. However, to do what you want, you will need to do some serious structural work, and you will certainly need an architect or engineer to draw up the plans.
Daniel Holzman is offline   Reply With Quote
Old 10-21-2009, 05:08 PM   #14
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Default

Can someone explain this Attic Space for me?!?!


With 21 feet width you have ~10' 3" span for the roof rafters
At 24" OC the 2x6's do seem to meet code depending upon the wood used = around 10' 9" Max
But that's bare min...I go with 2x10's Min just due to insulation needed

And then you have the short attic exterior walls
Collar ties keep the roof from spreading, but usually the rafters are then tied into the floor/joists below
In this case there doesn't seem to be support keeping those short walls from spreading out
That is probably the reason #5's may have been installed

Very different way of framing
I'd definitely want someone verifying the loads for me before I went pulling anything apart
Scuba_Dave is offline   Reply With Quote
Old 10-21-2009, 05:09 PM   #15
Member
 
Join Date: Jul 2007
Posts: 1,467
Default

Can someone explain this Attic Space for me?!?!


Anti-Wingnut - So there is only one right way and that is the conventional, practical, efficient way and anything else is wrong. Now you're sound like an absolutist wingnut which I assume by your name you are against. LOL

That structure would be very unconventional here and probably most places and I'm sure that pros on any forum always love to rip other peoples work if it is done differently than what they are use to.

But if the design numbers meet the local requirements and inspection criteria then it was done right whether it looks cobbled together or not. The design is a tragic waste of space and yes, silly (for lack of a better word) but might well be structurally sound and therefore "right" in terms of meeting local requirements. If left as is, it wouldn't surprise me if it holds up fine for the next 100 years.

jogr is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Cape Cod Style House Attic/Crawl Space Insulation Help Danielg Insulation 24 05-21-2012 08:20 AM
How to insulate attic crawl space RISurfer Building & Construction 7 10-01-2009 11:57 AM
Remodeling Attic Space befrenchy Building & Construction 4 09-21-2009 07:06 PM
Finished attic humidity? kcrossley2 HVAC 2 08-11-2009 05:06 AM
HVAC - Heating my Attic Space Vermont1 HVAC 7 02-01-2009 07:46 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.