What does this mean?

Help Support House Repair Talk:

Snoonyb

Supporting Member
Supporting Member
Joined
Sep 30, 2006
Messages
4,454
Reaction score
948
The rule in stick framing, is crown up.
 

bud16415

Fixer Upper
Staff member
Moderator
Joined
Feb 5, 2013
Messages
6,401
Reaction score
2,420
Location
Erie, PA
I'm with Snoonby. The way I was taught is you lay out your rafters or joists crown up and then you sort them placing the ones with the greatest crown in the center and work your way out to the straighter ones. I have had some with so much crown I snapped a line and cut the outside edge straight.

There could be other causes also but those would require something happening to the house.
 

Snoonyb

Supporting Member
Supporting Member
Joined
Sep 30, 2006
Messages
4,454
Reaction score
948
I was a framer for over 30yrs. so I'll just let you see the process, rather than read several paragraphs;
 

oldognewtrick

Administrator
Staff member
Admin
Moderator
Joined
Jul 26, 2009
Messages
11,890
Reaction score
1,953
Location
Nashville, TN
Very good chance it's been like that for a long time. But, go up in the attic and see if there's any cracked or sagging rafters.
 

Sparky617

Member
Joined
Nov 3, 2014
Messages
1,604
Reaction score
572
Location
Cary NC
Is your roof rafter and joist or truss? What is the sheathing? Plywood or OSB? What is the spacing of your trusses or rafters and joists? It is typical for trusses to be spaced wider than 16" OC and when 7/16" OSB is used for sheathing it will show waves/humps at the trusses. Architectural shingles can help disguise this. With rafter and joists the difference in crowns as mentioned by others can be significant.
 

BuzzLOL

Well-Known Member
Joined
Oct 26, 2015
Messages
290
Reaction score
144
Hi all,

it’s a bit difficult to see but I noticed my roof isn’t completely flat it has a bit of a curve (upward) by the bathroom? What does this mean?
Rafter roofs usually eventually sag a bit in the middle after a while... mine has 2 x 4 rafters, that actually measure 2" x 4" and of hard woods, and sags quite a bit... but after 200 years of snow falls it's still fine so I'm not worried about it...
Maybe a soil pipe is holding your roof up over the bathroom? Or there is some extra framing there...?
 

Latest posts

Top