Entering an Attic Bonus Room

We got this question from the Crown Group, a terrific HVAC firm in Uniontown, OH.bonus room1

What do we enter when we have a bonus room in the attic with a kneewall, a roof line and then a flat roof where the ceiling is under the peak of the attic. (See the drawing.)

The easiest way to think this through is to break it down into each component of the structure.

Bonus room wallsFirst, the walls (A on the drawing) –select the construction material in the wall section. Enter the width and height, and make it a partition wall by entering the STD and WTD.


Next enter the roof (B on our drawing).

Here you are going to have to do a little math; but it should be easy math. If the floor is 16 x 20 and the ceiling is 10 x 20 then you have 6 feet that is the roof section. Divide this in half to get 3 feet on each side of the room that is roof line.

On line 1 of the roof/ceiling section, select the material type from table 18 in roof section. Click on the down arrowBonus room roof slope next to either the length section. We’ll use the single slope section.

Here we enter the length as the distance from the wall to the end of the slope – our 3 feet. We also make the wall height the height of the kneewall – what we entered in the wall section.

We have the same condition of the other side of the room so you can just hit the F5 key to duplicate the two slopes –the one on the east side and the one on the left side. Now we have accounted for the two sloped areas.

Now enter another ceiling/roof. (If you don’t have three lines on the roof section click on the + symbol at the end of the Bonus room ceiling entry 2section to add a line.) This is the ceiling in the room that is under the attic space above. The material type will be chosen from group 16. The length is 16 less 6 or 10 feet, so change the length field to 10.



Your Room Data Screen will look like this.


If the room has slopes on all four sides then you enter four slope ceilings. Make sure you change the width AND length section to reflect the actual square footage of the ceiling under the attic space.


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