Step-by-Step Instructions: Installing Attic Trusses with Shed Dormer

Step-by-Step Instructions: Installing Attic Trusses with Shed Dormer

Installing attic trusses with a shed dormer is a complex construction project that requires careful planning and execution. It’s essential to consult with a structural engineer or an experienced contractor before starting to ensure that your design is safe and complies with local building codes. Here are general step-by-step instructions for the installation:

Materials and Tools You’ll Need:

  • Attic trusses
  • Shed dormer framing materials (wood or steel)
  • Plywood or OSB sheathing
  • Roofing materials (shingles, underlayment, flashing)
  • Framing nails
  • Screws
  • Hammer
  • Circular saw
  • Level
  • Tape measure
  • Chalk line
  • Safety gear (gloves, safety glasses, hard hat)
  • Ladder or scaffolding
  • Roof truss hangers (if needed)
  • Building permits (check local requirements)

Design and Planning

1.1. Consult with an architect or structural engineer to create detailed plans for your attic trusses and shed dormer. Ensure that your design meets local building codes and regulations.

1.2. Obtain any necessary building permits and approvals from your local authorities.

Prepare the Attic Space

2.1. Clear out the attic space where you plan to install the trusses and shed dormer. Remove any existing insulation and debris.

2.2. Inspect the existing roof structure to ensure it’s in good condition. Make any necessary repairs or reinforcements.

Install Attic Trusses

3.1. Hire a professional crane or a lifting crew to hoist and position the attic trusses in place. Ensure they are spaced according to your design and local building codes.

3.2. Use roof truss hangers or securely nail the trusses to the load-bearing walls, making sure they are plumb and level.

3.3. Install temporary bracing to hold the trusses in place until the shed dormer framing is complete.

Frame the Shed Dormer

4.1. Build the shed dormer frame using the framing materials specified in your plans. Make sure it aligns with the attic trusses and creates the desired roof pitch.

4.2. Secure the frame to the existing structure using framing nails or screws.

Sheath the Roof

5.1. Cover the entire roof, including the shed dormer, with plywood or OSB sheathing. Make sure to stagger the seams and secure the sheathing with appropriate fasteners.


6.1. Install the roofing underlayment over the sheathing, followed by flashing, drip edge, and starter strips.

6.2. Install the roofing material (shingles, metal, etc.) according to the manufacturer’s instructions and your design plans.

Exterior Finish

7.1. Finish the exterior of the shed dormer with siding, trim, and any necessary weatherproofing materials.

Insulate and Finish Interior

8.1. Insulate the attic space and shed dormer to meet energy efficiency requirements and keep the space comfortable.

8.2. Finish the interior of the shed dormer as desired, including walls, ceilings, and any windows or skylights.

Electrical and HVAC

9.1. If needed, install electrical wiring and HVAC (heating, ventilation, air conditioning) systems in the attic space and shed dormer.

Final Inspections

10.1. Schedule final inspections with your local building department to ensure that the installation complies with building codes and regulations.

Clean Up and Enjoy

11.1. Clean up the construction debris and ensure that the attic space and shed dormer are safe and functional.

11.2. Enjoy your newly expanded and functional attic space!

Remember that this is a simplified overview, and the actual process can be much more complex depending on your specific project and local requirements. Always consult with professionals and follow safety guidelines throughout the construction process.