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 08-13-2008, 09:27 PM   #1
Newbie
 
Join Date: Aug 2008
Posts: 5
Share |
Default

Diving in head first - is my roof crazy?


I had never built so much as a doghouse before April, but since then my friend and I have been working towards building our house. We're currently slip-forming the foundation walls, and are figuring things out as we go.

The outer dimensions of the house are 40'x40' (yes, square). We're planning a gabled roof with a 10' rise down the middle, so the slope is 6:12. I've read a bunch of books and been surfing the web madly, but I still can't figure out exactly what design will work best (or if any will work at all). So, I'm just going to dump all my ideas and questions, and maybe some brave soul will help me out if they're not driven away by my apparent insanity:

1) For a 20' run and 10' rise, we figured 24' rafters would give us a nice 1.5' overhang. It seems 2x12s might not be up to the task, even if I could stomach the cost of a 24' 2x12. Would I-joists work?
2) Do I need a ridgeboard? It would be 40' long... can I build it up myself like a box beam, or do I need something hardcore like 40' LBL beam?
3) Do I need roof joists? (They'd be 40' as well.) Do they help support the vertical load, or just keep the outer walls from bowing out and the rafters from twisting? (On the bright side, they'd serve as the attic floor.)
4) Can I get away without trussing so as to leave open the space above the attic floor for storage? Incidentally, we're only hoping to enclose the northwest quarter of the attic, the rest will be open vaulted space.

Also, this is for New Hampshire, so I guess figure something like a 50psf snow load.

Thanks!

odigity is offline   Reply With Quote
Old 08-14-2008, 12:58 AM   #2
Member
 
Join Date: Jan 2007
Posts: 2,384
Default

Diving in head first - is my roof crazy?


This post would be more adequately answered in the Carpentry sub-forum, so I will move it there for you.

Ed

Ed the Roofer is offline   Reply With Quote
Old 08-14-2008, 01:52 AM   #3
Newbie
 
Join Date: Aug 2008
Posts: 5
Default

Diving in head first - is my roof crazy?


Quote:
Originally Posted by Ed the Roofer View Post
This post would be more adequately answered in the Carpentry sub-forum, so I will move it there for you.

Ed

Thanks. I guess the "Roofing" sub-forum is more about shingling and tar paper and such than about framing. Oops.
odigity is offline   Reply With Quote
Old 08-14-2008, 05:52 AM   #4
Member
 
Join Date: May 2008
Posts: 567
Default

Diving in head first - is my roof crazy?


slip-forming the foundation walls ??????????????????????
wtf ?????????????????????????????????????????????????
' my apparent insanity ' is certain,,, that foundation'll either be so riddled w/cold jnts OR you finished in 1/2 day.
yesitsconcrete is offline   Reply With Quote
Old 08-14-2008, 05:57 AM   #5
Whatamess
 
Join Date: Jun 2008
Location: Costa Rica
Posts: 423
Default

Diving in head first - is my roof crazy?


How did you get a permit without a set of plans?
__________________
I may go home hungry, but not tired and hungry.
TazinCR is offline   Reply With Quote
Old 08-14-2008, 08:37 AM   #6
Registered User
 
Termite's Avatar
 
Join Date: Apr 2008
Posts: 6,520
Default

Diving in head first - is my roof crazy?


Quote:
Originally Posted by odigity View Post
1) For a 20' run and 10' rise, we figured 24' rafters would give us a nice 1.5' overhang. It seems 2x12s might not be up to the task, even if I could stomach the cost of a 24' 2x12. Would I-joists work?
I-joists can be used as rafters, but you need for them to be engineered by the supplier to ensure that they can do the job.

2) Do I need a ridgeboard? It would be 40' long... can I build it up myself like a box beam, or do I need something hardcore like 40' LBL beam?
Yes you do. You can't clear span 40' with anything made of wood. LVL, PSL, glulam...All will require center bearing at least.

3) Do I need roof joists? (They'd be 40' as well.) Do they help support the vertical load, or just keep the outer walls from bowing out and the rafters from twisting? (On the bright side, they'd serve as the attic floor.)
Assuming you mean ceiling joists. Yes, you need them to keep the walls from thrusting outward and the ridge from collapsing. Collar ties might be another option.

4) Can I get away without trussing so as to leave open the space above the attic floor for storage? Incidentally, we're only hoping to enclose the northwest quarter of the attic, the rest will be open vaulted space.
Roof trusses would probably be a good idea for you. The designer can allow for floor space, storage space, vaulted ceilings, etc.

I've got to ask...How on earth are you slipforming a residential foundation. Never seen or heard of that being done. How are you dealing with the cold joints?

If you've already started the foundation and haven't even figured out the roof, the cart is ahead of the horse...Bigtime. I'd hire an architect to assist you, or an engineer to help you specify the structural elements. If there is a permit on the job (from your post on another thread I'm wagering that there's not), the city inspector would be a valuable resource for you to get some answers about your house. Since you're obviously no framer, he could probably help you out by making sure it doesn't fall in on your head.
Termite is offline   Reply With Quote
Old 08-14-2008, 10:23 AM   #7
A "Handy Husband"
 
rjniles's Avatar
 
Join Date: Feb 2007
Location: South Carolina Low Country
Posts: 3,933
Default

Diving in head first - is my roof crazy?


Try this site for a roof framing calculator

http://www.blocklayer.com/roof/GableEng.aspx

rjniles 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
Flat roof questions, advice, ballpark estimate JerryH Roofing/Siding 18 11-07-2008 04:08 PM
Flat roof - Rolled? - leaks Advice? JJ2001 Roofing/Siding 4 11-19-2006 06:17 AM




Top of Page | View New Posts

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