In this video, I will cover creating attic trusses.
Attic trusses can be generated when there is an attic area on either side of a
living area and above another room,
such as a Cape Cod style house.
Let's take a look at the process by using an existing two story plan
and begin by building the roof. On the second story,
I'm going to come over into the build menu, down to roof, and build roof.
Inside of the roof build dialog,
I'm going to check the option to build the roof planes.
I'm going to use a 12 and 12 pitch.
I'm going to also check the option to use trusses,
and for the attic truss condition,
I'm actually going to ignore the top or the second floor by checking
the option.
Down below is the option also to raise the roof truss off plate.
For the purpose of this video,
I'm going to leave it at zero and we're going to go ahead and build the roof
with these conditions. While I'm on the second floor, you see two dashed lines,
but you don't see the roof planes.
If I move down to the first floor, you see the two roof planes.
This is because when I built the roof, I ignored the second floor.
I like to display these on the second floor,
even though I've gone through and explicitly said, ignore the second floor.
I'm going to go ahead and hold my Shift key down,
and I'm going to click on both roof planes and I'm going to display them on the
floor above by using the tool in my lower edit menu,
display on floor above. As I go back up to the second floor,
you now see the roof planes and you see the dashed lines where the ceiling,
you see in the diagram off to the side,
will be cut through the middle of the structure. To generate an attic truss,
I do need an attic room on either side of the living area.
Before I use the interior wall and draw in those attic walls,
I want to make sure that the floor platform is supported
and matches the bottom chord of the truss.
I'm going to use the bottom chord of the truss for the floor platform.
Let's double-click inside the room and take a look.
On the structure panel in the room dialog, down towards the bottom,
I'm going to come down in the floor structure area, click the edit button,
and you can see two layers, the sheathing layer and the floor framing area.
I am going to use the truss bottom chord for the floor framing.
Therefore I want it to match the two by 12 that I'm going use.
So I'm going to change this to the two by 12 dimensions at 11 and a quarter.
And then for the subfloor sheathing, I'm actually going to remove that.
I'm going to manage that through the floor finish since I don't want to have any
subfloor sheathing out in the attic areas and I also want to make sure
all the rooms are at the exact same elevation.
So I'm just going to remove that subfloor.
We'll take a look at that and the floor finish here in a minute.
In the floor finish area, let's click the edit button.
Since individual rooms can have different floor finishes and you can remove it entirely,
it will be easiest to add the subfloor in here really for the main living area.
I'm going to click insert above. I'll change the thickness to three quarters.
And then for the material,
I'll go ahead and click on the pattern and just do a search here for
plywood out of the plan materials.
And now the floor finish actually has the subfloor and the hardwood.
I'll just make sure that the order of these are in the correct order,
where the hardwoods on top.
And notice the change in the diagram off to the side.
Go ahead and close this dialog as well.
And now that I have the floor structure in place,
I'm ready to draw the interior walls and then designate the two sides of
those rooms as attic rooms. With the interior wall tool,
I'm going to come down,
click and drag to create the first wall and also the second wall.
With the temporary dimensions, click on the wall,
and I'm going to set both of these at 60 inches off the side.
Just type in 60 inches, set those. With my Shift key selected,
click in this room. And then on the room on the right, see the gray highlight.
We'll use the open button. On the general panel, for the room type,
I'll choose the option for attic room. Note when you have attic rooms,
on the structure panel, underneath the floor area,
there is a default of no floor finish when the room
type is attic.
Now the final step before I draw the roof truss itself is I want to look at the
framing defaults. I want to take the top chord and the bottom chord,
define those as two by twelves so I can make sure that I get the insulation
value in those two framing members.
I'm going to double-click on the framing tools and on the truss panel,
you can see that the top chord and the bottom chord,
I have already changed those to both two by twelves.
Leave the webbing alone at three and a half. At this point,
I'm now ready to draw the roof truss. Underneath the roof framing tools,
I'm going to come in, select the roof truss,
and click and drag across the structure. For this particular truss,
I'm going to double-click, open it up. You can see the truss has been generated,
and I'm going to choose the option to change this to an attic truss.
You can see the bottom chord generate.
You'll also see the two side attic walls or knee walls generate as
well. Using the back clipped cross section camera, I'll come in,
cut a section right through the truss. And you can see in a section view,
the attic truss is now using the bottom chord to support the floor.
If we zoom in on this area of the truss,
you can also see that I have a subfloor as well as a
finished floor inside the living space. And on the opposite side of the wall,
there is no floor finish because the room is marked as an attic.
To complete the truss design, move back over into the floor plan,
select the truss, use the multiple copy tool, hover over the truss,
and drag the trusses out. That's using a 24 on center copy interval.
Select the upper truss, use the multiple copy, hover over it,
icon changes. Click and drag the trusses,
and then using the perspective full framing overview camera,
generate a 3D view,
and you can see all the trusses that we've created for the attic trusses.
Well, that wraps up this video on creating attic trusses. To learn more,
please see the built-in help file as well as our other videos.
And thanks for watching.