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Sunroom Addition

A sunroom addition adds a light-filled room enclosed largely in glass, ranging from a three-season screened space to a fully insulated four-season room tied into the home's HVAC. It is priced per project and hinges on how the space will be conditioned.

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How sunroom addition is done

  1. Decide between three-season and four-season construction
  2. Pour a footing or slab for the sunroom base
  3. Frame the structure and install the window and glazing system
  4. Roof the addition and flash to the existing home
  5. Insulate and condition if four-season, then finish
  6. Install flooring, trim, and final inspection

What homeowners should know

  • Decide up front whether you want three-season or four-season use
  • Ask about glass options like low-E and insulated glazing for comfort
  • Confirm the roof tie-in is properly flashed against leaks
  • Consider whether the space will connect to your HVAC
  • Check that the foundation suits your climate and frost depth

Permits, timelines & things to consider

  • Permits are required, and four-season rooms must meet energy code
  • Three-season rooms cost less but are not comfortable year-round
  • Glazing quality is a major comfort and cost driver
  • Roof and wall tie-ins to the existing home are leak-prone details
  • Timelines typically run three to six weeks

Frequently asked questions

What is the difference between a three-season and four-season room?

A three-season room is uninsulated and not heated or cooled, while a four-season room is insulated, conditioned, and usable year-round at higher cost.

Does a sunroom need a permit?

Yes, sunrooms are additions that require permits, and four-season versions must meet energy code.

Will a sunroom leak?

Not if the roof and wall tie-ins to the existing home are properly flashed; poor flashing is the most common cause of sunroom leaks.