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View Full Version : Sistering roof rafters?


Montaukian
Mar 1, 2012, 02:59 PM
I have a 19 year-old roof with 2" x 10" roof rafters that are not of good quality wood; they were originally sistered on one side of some of the existing raftes with 2" x 10" boards but were apparently not fastened together properly (lag bolts) with not enough fasteners. The pitch of the roof is relatively shallow; it is not a steeply pitched roof.
What is the best way to insure a permanent fix considering the dimensions of the existing rafters and the amount of downward stress at the ridge?

ma0641
Mar 2, 2012, 07:28 AM
Downward loading on roof rafters should transfer to the outside wall. 2X10 is a pretty substantial rafter and I don't know why they would have sistered unless the existing rafter is cracked. Do you have collar ties across the rafters?

ballengerb1
Mar 2, 2012, 08:33 AM
Glued and screwed is the best mthod of sistering a rafter. How many roofs are on the bulding? One of the areas I have worked allows up to 3 roofs but that does cause the rafters to start bowing in some cases