Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

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

Reply
 
Thread Tools Search this Thread Display Modes
Old 06-18-2013, 11:55 AM   #1
Newbie
 
Join Date: Feb 2013
Location: Colorado
Posts: 26
Rewards Points: 12
Default

Rafter seat cut options


Traditionally most rafters have a birds mouth cut where they rest on the top plate (as shown on the left).
Is there any reason not to cut the seat as shown on the right with the rafter tail reduced in height?
Is there a code or practical reason for sticking with the birdsmouth?

I want to use the style on the right to leave more room for air to circulate in the eaves and eliminate the need for continuous soffit vents in a cathedral ceiling.
Attached Thumbnails
Rafter seat cut options-rafter-seats.jpg  

Tubafore is offline   Reply With Quote
Old 06-18-2013, 12:07 PM   #2
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 26,977
Rewards Points: 3,070
Default

Rafter seat cut options


I'm not seeing anyway the one on the right is going to give you more.
Looks like a lot less to be.
Unless your going to have this ceiling spray foamed I see no way your going to fit the required amount of insulation plus the baffles in that small an area.
http://www.energystar.gov/index.cfm?...sulation_table

__________________
When posting in forums, letting us know your location will help others give better feedback/advice/solutions to your questions
joecaption is offline   Reply With Quote
Old 06-18-2013, 12:20 PM   #3
Newbie
 
Join Date: Feb 2013
Location: Colorado
Posts: 26
Rewards Points: 12
Default

Rafter seat cut options


There will be a build down framework on the interior to give me the needed insulation depth.
Attached Thumbnails
Rafter seat cut options-eave-detail.jpg  
Tubafore is offline   Reply With Quote
Old 06-18-2013, 12:44 PM   #4
Member
 
Join Date: Apr 2012
Location: UK
Posts: 713
Rewards Points: 500
Default

Rafter seat cut options


Structurally there is no problem with the detail on the right.
tony.g is offline   Reply With Quote
Old 06-18-2013, 12:49 PM   #5
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
Rewards Points: 2,000
Default

Rafter seat cut options


You do understand that no matter the point of narrowing the rafters, a smaller fascia makes the house look cheaper. That's why trusses with just 2x4 top chords (tails) have larger 2x6 or 2x8 "hang-down" sub-fascias added to them.
__________________
"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
The Following User Says Thank You to Willie T For This Useful Post:
tony.g (06-18-2013)
Old 06-18-2013, 01:08 PM   #6
Newbie
 
Join Date: Feb 2013
Location: Colorado
Posts: 26
Rewards Points: 12
Default

Rafter seat cut options


The fascia will still be about 7" tall. This is an addition and it will match up well with the existing house.
Tubafore is offline   Reply With Quote
Old 06-18-2013, 01:13 PM   #7
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
Rewards Points: 2,000
Default

Rafter seat cut options


Quote:
Originally Posted by Tubafore View Post
The fascia will still be about 7" tall. This is an addition and it will match up well with the existing house.
Then I see no problem.
__________________
"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 06-18-2013, 01:33 PM   #8
Newbie
 
Join Date: Feb 2013
Location: Colorado
Posts: 26
Rewards Points: 12
Default

Rafter seat cut options


Awesome, thanks.
Tubafore is offline   Reply With Quote
Old 06-18-2013, 02:59 PM   #9
Member
 
GBrackins's Avatar
 
Join Date: Apr 2012
Location: Fairhaven, Massachusetts
Posts: 2,869
Rewards Points: 2,016
Default

Rafter seat cut options


I take it you are doing the work yourself? I ask because the additional time required to build down the ceiling for more insulation space.
__________________
Gary

"You get what you pay for, and sometimes free costs more!"
GBrackins is offline   Reply With Quote
Old 06-18-2013, 05:04 PM   #10
Newbie
 
Join Date: Feb 2013
Location: Colorado
Posts: 26
Rewards Points: 12
Default

Rafter seat cut options


Quote:
Originally Posted by GBrackins View Post
I take it you are doing the work yourself? I ask because the additional time required to build down the ceiling for more insulation space.
Yes I will be doing the work myself. There are a few reasons I chose this design. Even a 2x12 wouldn't give me the depth I needed for insulation without pricey spray in foam.
With R-38 batts plus the 1" foam board I will be using to create an air space this will give me a total R-44 value. Plus the drop down will break the thermal bridging that happens through solid lumber. All at a pretty reasonable price tag.
Tubafore is offline   Reply With Quote
The Following User Says Thank You to Tubafore For This Useful Post:
woodworkbykirk (06-18-2013)
Old 06-18-2013, 05:08 PM   #11
Member
 
GBrackins's Avatar
 
Join Date: Apr 2012
Location: Fairhaven, Massachusetts
Posts: 2,869
Rewards Points: 2,016
Default

Rafter seat cut options


sounds good, thanks for sharing

__________________
Gary

"You get what you pay for, and sometimes free costs more!"
GBrackins 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
Fascia board install - unlevel rafter tails giperbolic Roofing/Siding 3 01-17-2012 11:46 PM
Rafter Calculations - help me understand, please. wombosi Building & Construction 25 09-11-2011 10:48 AM
Rafter tie adjustment albanello Building & Construction 10 11-20-2010 10:26 PM
removing rafter ties: garage conversion neil_9 Introductions 0 09-29-2010 07:55 PM
Rotted Lookout Beam Supporting Barge Rafter rwbil Building & Construction 1 08-15-2010 11:40 AM




Top of Page | View New Posts

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