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Article Number 396

The information in this article applies to:
Home Designer Pro

Drawing a Dormer with the Manual Roof Designer

This tutorial shows how to draw a dormer using the manual roof tools.

To begin:

1. Start with a two-story plan with a gable roof with a pitch of 10" in 12" that sits low on the second story walls (about a foot high). The Ceiling Height of the second story should be 8 feet as in the Cross Section/Elevation. 
   
   
   
    
   
   If you are unfamiliar with the tools to create this type of structure, please begin with online Help Database Article Number 358: How to build a one and a half story roof automatically, before continuing with the steps outlined in this article to create your basic plan.
   
   
   
   
2. Go the Floor 2 of the plan in your 2D floor plan view, and select Build> Wall> Straight Interior Wall  and click and drag out an Interior Wall approximately 8' from the exterior wall.
   
   
   
3. Next, select Build> Wall> Straight Exterior Wall  and use this tool to create a room that will become the dormer.
   
    
   Remember to draw you walls clockwise so that the appropriate material will display on the exterior of the structure.
   
   
   
   
4. Go to Build> Wall> Break Wall  to select this tool and place breaks on either side of the knee wall inside of the dormer.
   
   
   
5. Now, use the Select Objects  tool to select the center wall segment created by the breaks, and click on the Delete  edit tool or the Delete key on your keyboard to remove it so that it looks like the image below.  
   
    
   
   
   
6. Select 3D> Create Render View> Render Full Overview  and you can see that the exterior walls are extending above the existing roof planes.
   
   
   
7. To correct this, go to Build> Floor> Rebuild Walls/ Floors/Ceilings  (or hit the F12 key on your keyboard) to update the 3D model to include recent changes.
   
   
   
8. In the Full Overview, select 3D> Delete Surface  and click on the roof planes to remove them from the 3D view. 
   
    
   
   In this view, you can see that the roof plane above has cut the dormer walls.
   

To extend the walls above the roof:

1. Close the Full Overview by selecting File> Close to return to the floor plan view
   
   
   
2. Select Build> Roof> Skylight  from the menu and draw a rectangular skylight that will become a hole in the roof plane where the dormer is located.
   
   
   Important Note: The rectangular skylight must be entirely within one roof plane.
   
   
   
   
3. Use the Select Objects  tool to select the rectangular skylight, and click on the Open Object  edit button to display the Roof Hole/Skylight Specification dialog.
   
   
   
4. On the General tab, uncheck the box next to the word Skylight, under Angle for Inside Hole Rim, select the radio button next to Plumb Sides and click OK to apply these changes.
   
   
   
5. Select 3D> Create Render View> Render Full Overview  to see that you now have a hole in your roof and the dormer walls extend through the hole in the roof. 
   
    
   
   
   If the walls do not extend above the roof plane, Rebuild Walls/Floors/Ceilings.

To give the hole the proper size and shape:

1.  Close the Full Overview by selecting File> Close to return to the floor plan view.
   
   
   
2. Use the Select Objects  tool to select the rectangular roof hole, and use its edit handles to move the hole near the three walls that define the dormer and the roof hole polyline sides should snap to the walls exterior layer.
   
   
   The edge of the roof hole that will meet with the valleys of the roof planes cannot be moved to its final position until the roof over the dormer has been created.
   
   
   
   
3. Select 3D> Create Render View> Render Full Overview  to verify that your dormer walls and roof hole meet properly. 
   
   
    
   
   
   If your dormer walls do not appear correctly, the roof hole may need to be repositioned. The edge of the roof hole should snap to the dormer wall's exterior layer.

To draw the roof planes upon the dormer walls:

1. Select Build> Roof> Roof Plane  and draw two roof planes to form a gable condition on the dormer walls.
   
   
   
2. Use the Select Objects  tool to select the appropriate edge of one of the newly drawn roof planes, click on the Join Roof Planes  edit button, then click on a second roof plane on the edge that should join to the selected edge of the first plane to connect them at the ridge.
   
   
   If you are unfamiliar with either drawing, or manually editing roof planes in Home Designer Pro, please review the Roofs chapter of your Reference Manual from within the software by selecting Help> Contents and Index . Select the Contents tab, scroll down to the Roofs chapter, and click on the plus + sign next to it to expand out the chapter.
   
   
   
   
3. Next, use the Select Objects tool to select the fascia edge of the roof plane containing the dormer, click the Join Roof Planes  edit button, and click on the valley edge of one of the dormer roof planes just drawn.
   
   We know this will not be possible, but the program will correctly position the dormer roof planes anyway, which is what we want.
   
   You could also locate the roof plane intersections manually.
   
   
   
4. Repeat this process for the other dormer roof plane.
   
   
   
5. Use the Select Objects tool to select one dormer roof plane, and use its edit handles to set the dormer roof plane gable overhangs.
   
   
   Consider temporarily turning off your snap settings, if you experience difficulty in correctly positioning the overhangs initially.
   
   
   
   
6. Select 3D> Create Render View> Render Full Overview  to see your progress so far. 
   
    
   
   The dormer roof planes look good, but the roof hole must be positioned correctly and our dormer wall must meet the roof planes above.
   
   

To adjust the shape of the hole to match the dormer valleys:

1. Close the Full Overview by selecting File> Close to return to the floor plan view.
   
   
   
2. In plan view, use the Select Objects tool to select hole, click the Break Line  edit button, then click on the upside edge of the hole to add a corner and drag the corner up to reshape the hole.
   
    
   The hole must remain contained within one roof plane.
   
   
   
   
3. Now, use the Make Parallel  edit button to align the hole edges with the edges of the roof plane valleys, then use the Select Objects  to select the edge of the hole and move it to the valley line.
   
   
   
4. Select 3D> Create Render View> Render Full Overview  to take a Full Overview to verify that the hole is the correct shape.  
   
   
   
   
   The roof hole should now be aligned with the dormer roof planes.

To raise the exterior dormer wall to meet the dormer roof planes:

1. Close the Full Overview by selecting File> Close to return to the floor plan view.
   
   
   
2. Next, use the Select Objects  to select the the Attic room created by the dormer (the inverse of the dormer) and give it an exterior Room Type such as Deck or Attic. 
   
    
   
   This will tell the wall it is an exterior wall and the attic wall will be correctly generated above it to close in the gap.
   
   
   
3. Alternately, you could take a Cross Section/Elevation View  of the dormer, select the wall, use the Break Line  edit  button to add an edge, and manually reshape the wall. 
   
   
    
   
   This wall will be maintained whenever you Rebuild Walls/Floors/Ceilings .
   
   
4. If you have not designated an exterior Room Type, when you try to place a window in the dormer wall you will be notified that you’re placing a window into an interior wall. Click OK to proceed. 
   
    

Now that you understand the basics of manually creating a dormer, you can customize this as necessary for your structure, such as by adding boxed eaves and corner boards as in our initial image in this article.

Article Number 236: How to build a gable dormer

Article Number 442: How to create an automatic dormer

Last updated on: 07-14-2010