Roofing Dimensions

This section explains the roofing dimensions layout that is included in the Construction Starter File.

The roof dimension layout will help you to estimate roofing and roof framing costs in residential and light commercial buildings.

Roofing DIMENSIONS BASICS
       When to Use | Entering Data

Roofing Details
       Gambrel Roofs | Mansard Roofs | Roof Additions

Other Construction DIMENSIONS
       Basic Dimensions | Foundations | Structural | Construction Details
       Exteriors | Windows & Doors | Finish Dimensions | Room Dimensions

Website Info Links
       Construction Estimating Software | Construction Software | Estimating Software

RELATED TOPICS
       Assemblies | Cost Items | Calculated Dimensions | Dimensions | Estimates

Roof Dimensions

The Roof Dimensions layout lets you enter measurements for roof framing and roofing materials.

Use it for new construction, additions, re-roofing and other projects that require some work on the roof.

Entering Roofing Data

Enter the following basic roof information:

Roof Type--  Choose the type of roof.
Horizontal Area under New Roofing-- Enter the total horizontal (plan) area under new roofing materials.
Horizontal Area under New Framing-- Enter the total horizontal (plan) area that gets new roof framing.
Main Roof Slope-- Enter the slope of the main roof, measured in inches rise per foot horizontal run.

Overhang at Eaves-- Enter the average roof overhang at the eaves (where water goes over).
Overhang at Rakes-- Enter the average roof overhang at the rakes (where water does not go over).
Parapet Height-- Enter the average height of any parapets, from roof surface to parapet top.

Enter the following information for gable ends:

Quantity-- The total number of gable ends.
Width-- The average width of each type of gable end from eaves to eaves.
Height-- The average height of each type of gable end, from eaves to peak.
Wall Area-- The total wall area within the triangle of a gable wall.

Enter the following information for dormers:

Dormer Type-- The type of each dormer roof (shed, gable or hip).
Quantity-- The number of dormers.
Roof Slope-- The average roof slope on dormers.
Height-- The average height of  dormers from roof to eaves.
Width-- The average width of the outside face of dormers.
Depth-- The average depth of dormers, at right angles to the width.
Wall Area-- The total side and end wall area for dormers.

Enter the following calculated roof measurements:

Hips-- The total length of hips (where roof surfaces come together in a sloping line).
Ridges-- The total length of ridges (where roof surfaces come together in a horizontal line).
Valleys-- The total length of valleys (where roof surfaces come together in a way that collects water).
Rakes-- The total length of rakes (where water does not flow over a roof termination).
Eaves-- The total length of eaves (where water flows over a roof termination).
Roofing Area-- The total area that receives a new or repaired roof surface.
Roofing Area in Squares-- The total roof area in squares (100 square feet).
Flashing Length-- The total length of flashing at junctions between roof and wall.
Parapet Length-- The total length of raised parapets.
Downspout Count-- The number of downspouts coming off the roof.

HINT-- Most of the unit costs in the Goldenseal construction estimating software refer to one of these calculated roofing dimensions.

Gambrel Roofs

A gambrel roof is similar to a gable roof, but it has two or more different slopes.  This is the traditional "barn roof".

To handle a gambrel roof, follow these steps:

  1. On the roof dimensions layout, enter Gable as the roof type.
  2. For the roof slope, use the average roof slope.  Take the elevation difference from eaves to the ridge peak (in inches), and divide it by the horizontal distance from eaves to ridge.
  3. Unlock the roof area, and add some extra area to compensate for the extra slope.  Take the total length of roof perpendicular to the ridge, and multiply it by the length of the ridge.
  4. You probably will also need to add a little to the area of the gable ends.
  5. You may need to add additional labor or materials for the extra framing, for flashing at the slope change, and for any extra scaffolding needed on the steep slope.

Mansard Roofs

A mansard roof is similar to a hip roof, but it has two or more different slopes.  Usually there is a low pitch on the main part of the roof, and a very steep pitch near the eaves.

To handle a mansard roof, follow these steps:

  1. On the roof dimensions layout, enter Hip as the roof type.
  2. For the roof slope, use the slope of the upper portion of the roof.
  3. Unlock the roof area, and add the extra area on the steep part of the roof (multiply the height of the steep portion times the perimeter of the building).
  4. You may need to add additional labor or materials for the extra framing, for flashing at the slope change, and for the extra scaffolding needed for the steep slope.

Roofing For Additions

Goldenseal computes roof areas that will cover all floor areas being worked on. It does not include the extra roofing or roof framing needed for roof "saddles" when you abut an addition to an existing building.

If you need to add additional roof framing or roofing on the existing building, add the extra area over the existing building to the roof area on the Roof Dimensions layout, and the roof framing area on the Structural Dimensions layout.

There may also be additional work you'll need to add to the estimate. Check for extra framing and flashing details at the junctions of the new and old roofs, extra costs due to temporary roof covers while the roofing is off, additional siding beneath shed roofs, and structural reinforcement of existing framing or trusses.