Heel height and fascia height

[AndrewSopher]

I am not sure if this is a bug but I wanted to see if anyone else is running into this same problem. I want my fascia lines to match up on varying roof pitches. My 4/12 pitch is set for a 12'' heel. The 12/12 pitch should have the same fascia lines with a 24'' heel (assuming they are both 1'6'' overhangs). My roof lines look good on the floor plan but when I take elevations you can see very slightly that the 4/12 pitch fascia line is 3/16'' lower than the 12/12 pitch. The fascia and sub fascia's of the roof planes are both the same and so is the roof overhangs. I worked out the math with Cad lines so I know the heel heights are correct. Does anyone have any solutions to this or did I miss something with my math?

[Michael_Gia]

5 minutes ago, AndrewSopher said:

I worked out the math

Just lock the pitch and enter the top of fascia height. 
 

If you try doing the math you’re going to have a really bad day.  Not worth it. 
 

Unless I misunderstood you, you seem to be asking that your fascias line up in an elevation view, right?

[AndrewSopher]

Just now, Michael_Gia said:

Just lock the pitch and enter the top of fascia height. 
 

If you try doing the math you’re going to have a really bad day.  Not worth it. 
 

Unless I misunderstood you, you seem to be asking that your fascias line up in an elevation view, right?

Yes, I definitely see what you are saying. But I guess what I am getting at is the fascia lines should match up with those heel heights unless I am missing something? I definitely could be wrong though!

[SHCanada2]

4 minutes ago, AndrewSopher said:

Yes, I definitely see what you are saying. But I guess what I am getting at is the fascia lines should match up with those heel heights unless I am missing something? I definitely could be wrong though!

 

Where are you specifying the heel height in CA?

[AndrewSopher]

Just now, jasonn1234 said:

 

Where are you specifying the heel height in CA?

I do it in the baseline height (but before I do it I make sure ahead of time that my roof dialogues are set up for trusses and not rafters). But I take the top plate in this case 218 7/8+12'' heel. And then 218 7/8+24'' heel for the 12/12 pitch. This almost always works out for the most part but it isn't in this case which is confusing. 

[SHCanada2]

I just added 12" and changed my pitch to 12:12 and get your same result

 

my guess is it due to the fascia board dropping for the change in pitch.

[SHCanada2]

 

Yes that appears to be the reason. if you draw a line across in a cross section, you can see the difference. 1/2" for the sub fascia and 3/16" for the fascia

 

 

 

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[AndrewSopher]

7 minutes ago, jasonn1234 said:

I just added 12" and changed my pitch to 12:12 and get your same result

 

my guess is it due to the fascia board dropping for the change in pitch.

That must be it!

[AndrewSopher]

12 minutes ago, jasonn1234 said:

 

Yes that appears to be the reason. if you draw a line across in a cross section, you can see the difference. 1/2" for the sub fascia and 3/16" for the fascia

 

 

 

f 

 

What would you do for a solution? I want the heels to be a friendly number? Is there really a solution to this ?

[SHCanada2]

however it is backwards to how one would think it should be, as the 12:12 pitch fascia board is higher in the above.

1 minute ago, AndrewSopher said:

What would you do for a solution? I want the heels to be a friendly number? Is there really a solution to this ?

 

I gave up on friendly number for trusses many a moon ago

 

[para-CAD]

Thickness of your fascia.  If you are calculating to the face of sub-fascia or tails, the thickness of the fascia will show up if the elevation is only seeing the outside face of the fascia. 
 

Im answering as a framer. I doubt it applies to Chief. 
‘We match fascia on actual buildings all the time. Pack up the steeper pitched roofs (taller HAP). 
 

[AndrewSopher]

7 minutes ago, para-CAD said:

Thickness of your fascia.  If you are calculating to the face of sub-fascia or tails, the thickness of the fascia will show up if the elevation is only seeing the outside face of the fascia. 

Yes, I am measuring to the sub fascia. So the reason it is off is because chief is calculating to the thickness of the fascia for the overhang ? 

[SHCanada2]

i have not checked but my guess is because the top of fascia board goes to somewhere in the roof sheathing. on the right, top of fascia aligns to middle of rood sheathing, on the left, it aligns to bottom

 

 

[SHCanada2]

yes, CA measures to outside of fascia. you can see the 1'6" above. I think I logged a support request indicating the doc was incorrect a few months ago

[AndrewSopher]

10 minutes ago, jasonn1234 said:

i have not checked but my guess is because the top of fascia board goes to somewhere in the roof sheathing. on the right, top of fascia aligns to middle of rood sheathing, on the left, it aligns to bottom

 

 

So the heel height is correct for 12 and 24 and this is more of a bug ? 

[AndrewSopher]

11 minutes ago, jasonn1234 said:

yes, CA measures to outside of fascia. you can see the 1'6" above. I think I logged a support request indicating the doc was incorrect a few months ago

I see the 1'6'' above, interesting, so the bug is that the fascia board is going 3/16'' into the roof sheathing? 

[SHCanada2]

Just now, AndrewSopher said:

So the heel height is correct for 12 and 24 and this is more of a bug ? 

no i do not think so, and i figured why it is higher on the 12:12, the 2x4 will have a taller vertical depth

[SHCanada2]

no it is not a bug, if you set the eave inside of the facia to be 1'6 and measure the top side of the rafters with a line accross, ti will match

 

 

 

 

[AndrewSopher]

8 minutes ago, jasonn1234 said:

no it is not a bug, if you set the eave inside of the facia to be 1'6 and measure the top side of the rafters with a line accross, ti will match

 

I did this out on cad showing the heel heights of the 4/12 and 12/12 roof pitch. The other designer I work with uses auto cad and also did the same thing to for his heel heights, not sure where I went wrong?

 

[SHCanada2]

not sure, but it is not CA:

 

you need to put the facia on your drawing, vertically dimensioned. the thickness of the fascia will move the 4:12 line out, but the 12:12 line will go down

 

[SHCanada2]

fill in your CAD drawing with the 2x4 top chord, sheathing, and the fascia. I think you will come to a similar result

[AndrewSopher]

I see what you mean, I talked to our other designer and he said he cheats a little bit with that overhang and keeps the heel heights at 12'' and 24'' and they make a field adjustment so the fascia and sub fascia matches up. Is that what you would do or have done in the past? 

[Alaskan_Son]

There's 2 big things to think about here:

1. Chief measure the baseline height from the top of the framing (NOT the top of fascia).  This means you may need to take both sheathing thickness and fascia thickness into account.
2. When dealing with multiple pitches and assuming the same size lumber if used for the corresponding components on each roof, you can only ever align ONE component horizontally.

You can align top of rafter, you can align bottom of rafter, you can align top of sheathing, you can align bottom of sheathing, you can align fascia, or you can align subfascia.  You can only pick one though.  Something has to give.  In the real world, in order to get pitches like this to line up we have to use different sized sub-fascia, shifted sub-fascia, clipped tails, etc.

[GeneDavis]

What Michael said.  And remember, Chief's fascia has its top outside corner (top of fascia) aligned with the top face of sheathing.  That point, that corner tip, is not colinear with the point that is the baseline height, or the point that is the ridge height.  Those two are at top of framing.

 

Math will deliver you the number for your 12 pitch as it relates to 4 pitch, with roofs having same fascia height and fascia thickness.  For 3/4 fascia, Chief delivers the math result, and the heel height difference is not 12 inches, but 11.8133704333".  No bug.  Real trig.

 

I always dimension plans to show overhang to tip of fascia, and let the truss engineers and framers do the math for how to build.

[SHCanada2]

6 hours ago, AndrewSopher said:

I see what you mean, I talked to our other designer and he said he cheats a little bit with that overhang and keeps the heel heights at 12'' and 24'' and they make a field adjustment so the fascia and sub fascia matches up. Is that what you would do or have done in the past? 

No,

 

I align the fascia per Micahel_Gia's note.

 

The truss details I have seen from a truss company are filled with 16's of an inch measurements. I specify the heel height based on CA's Truss detail, by taking a p2p measurement from that detail. This gives the truss company everything they need to know, heel height, pitch, dimension from wall to wall from normal floor plan, and eave dimension.

 

However, I have had calls from the truss guy asking if the eave dimension is from the top plate edge, or from the sheathing, and does it include the sub fascia, fascia. But some contractors like the truss to end at the sheathing, so, i have a note leaving it to them to figure out the eave/overhang portion. The critical measurement here is to outside of fascia, as there are building code regulations to property line.

 

And from talking to framers on the "where to land the subfascia/fascia", it is not exactly like the pictures, they will line up the corners one way or another, and some of it is not pretty

 

You should also check out the Build roof dialog on how to maintain same height eaves:

 

• Check Same Height Eaves to keep the eave height for all roof planes the same. Roof planes are raised and lowered as needed so that eaves meet correctly.
  
  The eave height used when this box is checked is that of a roof plane using the default Pitch and Overhang values. When this box is checked, all roof planes are affected, including those that do not need adjustment in order to align with adjacent planes.
  
  When Same Height Eaves is checked, any non-default overhang values specified in the Wall Specification dialog are used. Roof planes are raised or lowered so that the eave height is the same, regardless of the horizontal overhang.