Gable Roof With Trusses Overhang

[mark2457]

Hi Guys

 

Was looking at stock trusses (24' 4/12 24" OC). My local Menards carries these, but the end truss is same height as common trusses. They don't seem to have a stock dropped gable end (I know I could get one custom made).

 

I was planning on at least a 1 foot overhang (maybe 2'). Is there a way to do this without notching the top chord (probably not a good idea ) or just nailing the fly rafter to the sheathing (i know some people do that, but I'm not sure it's a good idea).

 

Only way I can imagine doing it (with stock trusses) is reducing height of end wall to give me the clearance for the lookouts and then build it up where required

 

Any other suggestions

 

Regards

 

Mark

[rlackore]

You can build an over-hanging rake without a dropped-top-chord end truss, but I would not go over 1 foot. A continuous subfascia and the sheathing will help support the barge rafter; use lookouts as well. I'm not necessarily recommending this approach, but it's done. I would also consider the pitch of the roof and the anticipated snow load in Chicago.

[mark2457]

You can build an over-hanging rake without a dropped-top-chord end truss, but I would not go over 1 foot. A continuous subfascia and the sheathing will help support the barge rafter; use lookouts as well. I'm not necessarily recommending this approach, but it's done. I would also consider the pitch of the roof and the anticipated snow load in Chicago.

 

Thanks. I just got a quote from midwest manufacturing (Menards' supplier)

 

I looked up Chicago span tables and they had 4/12 listed. They have a load factor (which is 1.0 for under 30-degrees) for snow load. Having dinner with an architect friend on Thursday and will ask him what local snow load requirement is. Max ridge height I can have is 15' and wanted 10' ceiling. If I have to, I could drop to 9' walls and 5/12 pitch. I'm also waiting on quote on scissor trusses, which would give me the ceiling height I want in the middle (without needing 10' walls)

 

thanks again

 

Mark

[MickeyToo]

Mark, you could notch the top chord of the gable truss to accommodate the (2X4?) lookouts and then sister a rafter under the lookouts on the inside of the the gable truss. And still do the continuous sub-facia, as was suggested.

[rlackore]

Mark, you could notch the top chord of the gable truss to accommodate the (2X4?) lookouts and then sister a rafter under the lookouts on the inside of the the gable truss. And still do the continuous sub-facia, as was suggested.

 

It depends on the depth of the truss top chord.

 

Another solution would be to frame a gable end wall - then lookouts could be used to achieve a deeper rake.

[CJSpud]

I don't believe truss top chords should be notched so never show that on the plans I prepare.  I know that some builders will notch gable truss top chords but I have never seen any gable trusses designed for this practice.  Maybe its OK ... ???   Maybe it's a carry-over from framed roofs where the gable rafter is notched for outriggers?  Maybe it is something that the building inspectors are missing or turning their heads on .... ???

 

If I have gable overhangs of 12" or less and there's no extreme snow loads to worry about, I do as Robert suggested ... just show blocking [on edge ... not 'flat'] between the gable truss top chord and the barge rafter as shown below.

 

 

In the above image, I had to edit the positions, dimensions and end locations of Chief generated "flat" lookouts.  I do this in both a back clipped section and in plan view.

 

If I am doing gable overhangs greater than 12", then I drop the gable truss tops the depth of the truss top chord, and then edit the Chief generated lookouts as needed similar to what I did above.  Like the trusses, I put the blocking or lookouts on 24" C.C.  Here's one with a 24" gable overhang, 2x4 lookouts 24" C.C. and with the reduced gable truss top chord edited to match the bottoms of the 2x4 lookouts. 

 

 

The typical Chief generated lookouts and reduced gable is shown unedited on the opposite end (right side).  I wish Chief would build these darn things according to the way we plug the dimensions into the roof framing defaults.  I need to put that in the suggestion box.

[mark2457]

I don't believe truss top chords should be notched so never show that on the plans I prepare.  I know that some builders will notch gable truss top chords but I have never seen any gable trusses designed for this practice.  Maybe its OK ... ???   Maybe it's a carry-over from framed roofs where the gable rafter is notched for outriggers?  Maybe it is something that the building inspectors are missing or turning their heads on .... ???

 

If I have gable overhangs of 12" or less and there's no extreme snow loads to worry about, I do as Robert suggested ... just show blocking [on edge ... not 'flat'] between the gable truss top chord and the barge rafter as shown below.

 

CAGableFrmgStdGableTruss-Edited.JPG

 

In the above image, I had to edit the positions, dimensions and end locations of Chief generated "flat" lookouts.  I do this in both a back clipped section and in plan view.

 

If I am doing gable overhangs greater than 12", then I drop the gable truss tops the depth of the truss top chord, and then edit the Chief generated lookouts as needed similar to what I did above.  Like the trusses, I put the blocking or lookouts on 24" C.C.  Here's one with a 24" gable overhang, 2x4 lookouts 24" C.C. and with the reduced gable truss top chord edited to match the bottoms of the 2x4 lookouts. 

 

CAGableFrmgReducedGableTruss-Edited.JPG

 

The typical Chief generated lookouts and reduced gable is shown unedited on the opposite end (right side).  I wish Chief would build these darn things according to the way we plug the dimensions into the roof framing defaults.  I need to put that in the suggestion box.

 

Thanks. I agree about the notching.

 

There's nothing in spec for the trusses I got quoted about notching, so i wouldn't do it and risk failing an inspection (even if structurally sound).

 

When I added the trusses there was an option to drop the end for lookouts and it put the lookouts in (I'm using HDPro10). Is that what you were referring to, or something else missing?

[MickeyToo]

Mark and Curt,

 

What is essentially being done in my suggestion is stick framing a dropped gable end (the notching being rather incidental). All of the loading on the lookouts will be on the rafter that is sistered to the inside of the truss (and carried to the wall plates), and to some extent on gable truss studding, which remains fully intact.

 

But good luck either way!

[CJSpud]

Mark:

 

I don't have that program so I am not sure if what you are asking is exactly the same as what X7 premier has in its' dbx.  I suspect that they may be the same or very similar.  Here's the two dbx's that are used in X7:

 

    

 

In X7, it appears to me that Chief will build with lookouts even if there is no reduced gable specified or no lookouts specified.  In the image below, this is what X7 generates with the lookouts box unchecked, max. lookout spacing set for 24" and with a standard gable truss.  Note that the "in plane" spacing of the non-lookout lookouts is 40".  Why Chief didn't just generate blocking between the truss and the barge rafter at 24" C.C. is beyond me ... and generate them on edge like I asked them to be.  [For the roof framing shown below, I did in fact uncheck "Lookouts" but Chief put them in (from the barge to the 1st inboard truss) but Chief built them anyway]

 

 

So, to summarize, there can be several improvements made to the way Chief X7 Premier does its roof framing IMO.  When I get time, I will submit my ideas on some improvements that I would like to see on the Suggestion forum.

[CJSpud]

Mickey:

 

I am sure your methods are perfectly fine or you would probably have the alligators nipping at your heels.  Around my area, trusses are pretty much the norm for roof construction and in the more populated areas, roof snow loads are relatively low (30 to 40 lbs).  Truss top chords are quite often just 2x4's.  I would never want to see a builder notching a 2x4 gable truss for lookouts for the overhang, unless the truss designer specifically called for that on the truss design documents.

[mark2457]

Mark and Curt,

 

What is essentially being done in my suggestion is stick framing a dropped gable end (the notching being rather incidental). All of the loading on the lookouts will be on the rafter that is sistered to the inside of the truss (and carried to the wall plates), and to some extent on gable truss studding, which remains fully intact.

 

But good luck either way!

 

Thanks Mickey

 

Sounds OK, but I did manage to get a quote from a dropped gable (so I think I'm all set)

[mark2457]

Mark:

 

I don't have that program so I am not sure if what you are asking is exactly the same as what X7 premier has in its' dbx.  I suspect that they may be the same or very similar.  Here's the two dbx's that are used in X7:

 

RoofTrussDbx.JPG     RoofFramingDbx.JPG

 

In X7, it appears to me that Chief will build with lookouts even if there is no reduced gable specified or no lookouts specified.  In the image below, this is what X7 generates with the lookouts box unchecked, max. lookout spacing set for 24" and with a standard gable truss.  Note that the "in plane" spacing of the non-lookout lookouts is 40".  Why Chief didn't just generate blocking between the truss and the barge rafter at 24" C.C. is beyond me ... and generate them on edge like I asked them to be.  [For the roof framing shown below, I did in fact uncheck "Lookouts" but Chief put them in (from the barge to the 1st inboard truss) but Chief built them anyway]

 

GableRoofFramingXSec.JPG

 

So, to summarize, there can be several improvements made to the way Chief X7 Premier does its roof framing IMO.  When I get time, I will submit my ideas on some improvements that I would like to see on the Suggestion forum.

 

Agreed. Certainly looks odd