Drawing Attic Trusses for Roof

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bandersen
bandersen's picture
Drawing Attic Trusses for Roof
SoftPlan Version:
2014

Very confused about how to draw attic trusses with built in 20" floor system into trusses, and then adding a 16" heel height to Rear section trusses with 6/12 pitch. 

Front Section trusses with overbuild on rear section trusses=  5'6" heel height in which 20" of this is floor system built into the trusses with a 8/12 pitch.

Can anyone please give me some guidance?  Would appreciate your help.

Bill Wimberley
Bill Wimberley's picture
Trusses

The Heel Heights and pitches are determined by the roof. So set your heel heights and pitches that you want by editing each roof edge.

From your description it sounds like you need to set your trusses to "Attic" style. Then set the bottom chord to 20". In the Attic Size settings for the truss adjust the height and width as appropriate. The trusses will adjust to match the roof. You may need to do a Cleanup, Ctrl+C, to get the trusses to adjust if you make any adjustments to the roof after you insert your trusses.

For your overbuild trusses just put in a single truss and place it 24" or whatever your spacing is from the closest existing truss. Then offset that truss your spacing distance several times until the area is filled. Then do a Cleanup to adjust the overbuild trusses to their proper size.

Bill is the owner and maintainer of SoftPlanTuts.com

bandersen
bandersen's picture
Attic Trusses with built in floor system.

Bill,

I appreciated your advice, very helpful.  I am sending another rough sketch that I'm hoping will help explan what I'm trying to accomplish.  To try and better

explain myself, the Truss Company has drawn trusses for my roof and they have on the back main section by the patio, attic trusses that have a heel height of 16" at the plates and inside the trusses is built-in a 2o" high floor system as shown per attachment. I guess my question is?  How do I draw these trusses with Softplan v.2014?  I have previously drawn the standard floor system being 20" tall plus .75" sheathing (noting that the floor system is only in the centers of the roof spans with the exceptions of the Dormers) but the problem I'm having is that after doing this, the trusses lift off the plate the 20" also.  I'm wanting the truss ends with the heel heights of 16" to be at plate level, not 20" up from plate level.Hope this makes sense after looking at my sketch I'm attaching.

    I've never done attic trusses before and it seems a bit challenging for me.  

Secondly, I would like to understand if I need to be using interior ceilings mode for this application?  So as to when I do a cross section it would show up with sloped ceilings with the flat collar tie showing?

Hope this all make some sense... Appreciate it so much!!

Brent

Bill Wimberley
Bill Wimberley's picture
Trusses

Hey Brent. Well first of all SoftPlan is not a truss design program. It contains a few types of trusses that you can use for "illustration purposes" but it will not handle every possible type of truss. Your best and easiest way to do your cross sections is to just leave the trusses off and then just draw them in on your cross section. That is the only way you are going to get something that looks anything like what your truss company sent you. You will still need to set the proper heel heights on the roof edges so your cross sections will be accurate. But trying to replicate what your truss company sent by using SoftPlan's trusses will take a lot more time and you won't be able to get the trusses exact. Fiddling around for a couple hours with trusses vs a couple minutes drawing a few lines would be a no-brainer to me.

bandersen
bandersen's picture
Attic Trusses with 20" built in floor system and 16" heel height

I'm sorry that I have drawn you to the wrong assumption of what I'm trying to accomplish. I'm not really trying to replicate the drawing of the trusses but what I am trying to do is trace a roof with trusses with a heel height of 16" with a 20" tall floor system inside the attic area.  When I draw the 20" floor using floor system mode the bottom chord of the trusses offset up the 20" and I want them to stay at main level plate height.

    I only sent the drawing of the attic truss to basically rough show how the truss design would be manufactured at the truss company.

I just want the proper heights of the bottom chord of the truss with the 16" heel height and the 20" floor system at their proper heights, so when I do an elevation and use dimensions and extensions that the heights comes out correctly.

    Hopefully I've explained the situation better this time around. 

 

 

Bill Wimberley
Bill Wimberley's picture
Confusion abounds

Have you edited the roof edges and set the heel heights to 16" as I suggested earlier? It seems that is what you are trying to do. The floor system has nothing to do with the roof, unless you place a wall on the floor system and then attach the roof to that wall. Other than that the floor system does not affect the roof in any way.

Also, make sure you are treating your attic floor system as a 2nd floor. In other words the attic floor would be in a different file, just like a 2 story house. If you try drawing a floor system on the first floor and then offset it up in an attempt to create an attic floor system you can run into all sorts of problems because the first floor walls will be trying to move to sit on top of the floor. Alternately, you could use a ceiling system rather than a floor system and you could do that all in one file. Then you could use a solid polygon or a cube set on top of the ceiling joists if you need to show a floor system for cross sections or 3D.

But if all you care about is getting the roof to look right for elevations forget about the trusses and floor system. All you need to do for the elevations is set the heel heights on the roof to 16" or whatever the specs for the truss says.

If there is something else you are asking about perhaps you can show a 3D view of the framing and explain what is not working right.

bandersen
bandersen's picture
Bill,

Bill,

I think your advice will be just what I was looking for.  I won't be able to attempt this until the first of the week because of my schedule, but I will try your 

thoughts then and will get back with you on how things work out.  

Do appreciate your patience!!

Brent