# Is 22' ridge board too long of a span? Worried about roof sag



## myboynoy (Feb 15, 2013)

I was planning on creating a 22' ridge board out of 2 pieces of 12' 2x10s but now am wondering if 22' is too long and could cause roof sag in the middle? The rafters would be made of 2x6 at a 6/12 pitch.

What do you think? See attached screenshots of plan vs. what I have completed thus far.


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## de-nagorg (Feb 23, 2014)

What's the snow load in your area?

I would make it a triple width beam, with the joints at 1/3 the way on the first sister, then 1/2 the way on the middle, and 2/3 the way on the back sister.

This gives you at least 2 boards holding up the cut one at each joint. 

It will be heavy to lift up there after building it, but will support the rest well. 

Build your end supports first, then the ridge beam, and lift one end up, tir it off well, then lift the other end up and get it placed and anchored, at both ends, and add all the rafters you want, sheath it, shingle it. done.


ED


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## Msradell (Sep 1, 2011)

If you're going to have joists from wall to wall keep the walls from bowing outward all the rigid beam actually does is act as a joining point for the rafters, it actually does nothing structurally. You could actually use a piece of 1x for the rigid beam.


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## carpdad (Oct 11, 2010)

Second on NO on ridgebeam. You haven't planned for a load bearing beam anyway. If you wanted a beam, there would be posts at the ends and wall posts and bigger footings below. Your plan is using ridge board (or none) and rafters leaning on each other to keep the triangle shape. In that case the load is on the ends that wants to push the walls apart and you need ceiling joists/ceiling collar/cables to keep the walls together. Check the difference between rafter vs ceiling ties. A ridge board doesn't need to be in one piece. You can use 2 pieces with the joint between the rafters. Use a scrap over the joint to connect.
Also in the drawing, the gable overhang needs a long 2x facia board or better is double rafter as a beam and cantilevering joists that span at least 3 rafter bays.


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## rjniles (Feb 5, 2007)

The ridge could be 100 ' long, it is supported by the rafters. You need rafter ties or ceiling joists to prevent the walls from bowing out. In your mock up I see neither.


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## Yodaman (Mar 9, 2015)

Pre-built trusses work real well here. You can buy them or make your own.


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## Daniel Holzman (Mar 10, 2009)

A few comments on terminology. A ridge board, which is what you show, is simply a board used to allow for convenient nailing of the rafters. This has been commented on already. A ridge board need not be continuous, and it is typically sized so it is the depth of the rafter. A ridge beam is a structural element designed to hold up the roof, therefore a ridge beam is a typically large structural member, and it must be supported by posts on either end, sometimes with an additional post in the middle to reduce the required depth of the beam.

A ridge beam has the advantage that there is no outward thrust on the walls from the rafters, so there is no need for ceiling joists to hold the walls together. Therefore use of a ridge beam is common when designing a vaulted ceiling. The connection between a ridge beam and the rafters must be strong, therefore metal brackets are typically used.

Collar ties are typically light boards attached about two thirds up between the ceiling and the peak of the roof. Collar ties do not stop the walls from spreading, that is the job of the floor joists. Rather the collar ties equalize uplift pressure on the roof during high wind events. Not all jurisdictions require collar ties, check with your local building inspector if they are required where you are. You do not need collar ties if you use a ridge beam, only with a ridge board system.


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## SevenHillsCC (Nov 28, 2016)

Like was said above, if you've never framed a roof before (or even if you have), I would definitely consider a prebuilt truss it's going to make your life a lot easier. Absent that, you have a non-structural ridge so it doesn't matter what size the lumber is but you need to make sure to have rafter ties to hold your exterior walls together, I don't see those on the rendering. The beam is only structural if you don't want to use rafter ties, like for a vaulted ceiling.


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## firehawkmph (Dec 12, 2009)

If I was framing that roof, I would run 2 x 6 ceiling joists all the way the length of the building. Then I would go ahead and install the ridge and start cutting and installing rafters in opposite pairs. Start with the ends, make sure the ridge is level, then run a stringline down the middle of the top edge of the ridge. When installing rafters, it's easy to shift the ridge over to one side or the other. The string gives you a visual on whether or not your keeping it straight. If you lay it out right, your rafters will sit right against your ceiling joists. Toenail the joists into the top plate, do the same with the rafters, the. Nail the two together where they overlap each other. Use a 2 x 6 for the fascia boards as suggested above to tie in the gable overhangs. When you go to sheet the roof, don't have any seams fall on the rafters that the overhang is attached to. Stagger each succeeding row 4'. For 16" centers on the rafters, you don't normally need plywood clips. 5/8" cdx makes a solid roof. Also, you might be able to find a 22' long 2 x 8 for the ridge, check with a real lumberyard, not the big box stores. 
Mike Hawkins


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## roobinsteen (Apr 25, 2015)

As has already been said here, you are probably confusing the terms ridge BOARD, and ridge BEAM. if you want an actual ridge BEAM, you need a much, much bigger piece of lumber. My guess is you don't want that--as long as you use "ceiling" joists to connect the rafters, you can make your ridge board out of the same size lumber as your rafters.


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## firehawkmph (Dec 12, 2009)

Ridge board is usually upsized a couple inches in width to allow for the longer length of the plumb cut on the rafter. i.e. 2x6 rafters, 2x8 ridge, etc.
Mike Hawkins


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## myboynoy (Feb 15, 2013)

Thanks everyone! I ended up joining 2 2x8x12's with 3/4" plywood gussets for my 2x6 rafters. The gussets are in between rafters.

You're right, even with the gable end rafters up, the ridge board is staying up, and I will be adding collar ties and ceiling joists every other rafter.

See attached photo.


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