Replies

1. 
   Piffin | Sep 20, 2009 05:16pm | #1

   28' is a tremendously long span for regular framing lumber.
   Are you sure that you don't mean that the house is 28' wide and the rafter covers a 14' span?

   Best way to replace depends on lots of variables and your skill level.

   Do you know why is it fractured? is the split lengthwise AKA checking, or is it broken from loads?

   what is the layout and size of what this house has now?

   What is the access into the attic?
   or are you re-roofing and see this from oppen above?

   Not all roofs need collar ties.

   Got any photos?

    

    

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1. 
   hammercat | Sep 20, 2009 10:43pm | #3

   you're right- the width of house is 28- rafter span is 14' and length of rafter is 16'3".

   the reason it cracked is probably due to snow load- last couple of winters here have seen plenty of it.  The previous owner was in a nursing home and house wasn't tended for a few years. I'm making it whole again.

1. 
   Piffin | Sep 21, 2009 03:08am | #6

   OK, that is two answers Now the rest of th e quiz again...what is the layout and size of what this house has now?What is the access into the attic?
   or are you re-roofing and see this from oppen above?Not all roofs need collar ties.Got any photos?Need information to be able to help. 

    

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1. 
   hammercat | Sep 21, 2009 03:04pm | #7

   roof access is thru the gable vent-  simple rectangular, gable roof, which is 25 years old, but shingles are remarkably in good shape and I don't want to mess with them as long as they are doing their job.  cracked rafter is in the middle of the roof (and roof is visibly sagging when you look at it from outside)- house is 28 x 38- rafters are 2x8 with a 1x ridge board (never seen that before) sorry- I don't have a picture

    

1. 
   Piffin | Sep 21, 2009 06:24pm | #8

   The question what layout means are they laid out at 16"OC, 24" oc, or something else. Since this is stick framed I can assume 16"That layout with 2x8 should do you pretty well, unless there is a tremendous snow load or previous damage had been done to the rafter from reroofing or even at construction time. You don't want to need to pull in enough lumber to sister all of them. What snow load do you get there? Locality information?So just sneak a new one in thru that access, jack the broken rafter straight, then sister to it. I would inspet for sgns of sagging and stress on the others and maybe sister a few more of them.You have a ridge board instead of a ridge beamm which would only be needed where you have a cathedral cieling or any other situation requiring structural ridge. 

    

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2. 
   hammercat | Sep 22, 2009 04:13pm | #9

   Thanks for your help- Yes they are 16" oc-  to jack the rafter back up into position, I assume I would spread the load several feet across the ceiling rafters (no deck up there) and work a type of "knee-wall" under the area where the crack is (I don't want to go through the ceiling or bow those joists).  then glue (construction adhesive)and nail the sister to the rafter.  And check other rafters for sag or cracks and give them help if needed.

3. 
   Piffin | Sep 22, 2009 10:10pm | #11

   Yes. To span those several other ceiling joists, make an L by nailing a couple 6' long 2x6 or 2x8 together. Then a short 2x4 scrap from it to the rafter in question wedged in and pushed tighter in the descending slope will generally work it up. If it is really bad, you will need a hydraulic, or for light weight maybe the car screw jack. 

    

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4. 
   hammercat | Sep 22, 2009 04:18pm | #10

   oh, about the snow- last year we got about 5 feet over the season, but that was also mixed with sleet and rain so there were layers we couldn't get off until they melted.  shoveling the roof is a regular winter chore here and we did it three times.  I wasn't living there then and had to make a 1 hr 15 min trip each time to do it.  Normally, if you get 5-6" on the roof you get out there and clean it off.

2. 
   excaliber32 | Sep 20, 2009 08:47pm | #2

   I'm just going to assume you need a repair, not replacement. You can either scab or sister a piece of lumber at the cracked area or the entire length of the rafter. It really depends on the extent of the damage.

   If it is just the one rafter, I wouldn't imagine that the roof structure is inadequate.

1. 
   hammercat | Sep 20, 2009 10:46pm | #4

   would adding collar ties help the other rafters hold up under snow-load in the future? just want to be sure if I'm not around to shovel off the snow will it take the weight?

1. 
   Piffin | Sep 21, 2009 03:05am | #5

   That is not the purpose of collar ties. 

    

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