Calculators

Soundproofing and fire-rated assembly calculators

STC estimates for wall and ceiling assemblies, Green Glue, mass-loaded vinyl, acoustic insulation, fire-rated layers and isolation clips.

A sound or fire rating belongs to a tested assembly, not to a product. The Gypsum Association's Fire Resistance and Sound Control Design Manual (GA-600) and the manufacturers' own test reports list what was built, how it was fastened and what it scored. These calculators let you pick an assembly that matches a published one and then count its materials: the layers of board, the screws for a double layer, the tubes of damping compound, the batts, the clips and the channel.

Where your assembly is not one that has been tested, the calculators give a range from the nearest tested ones and say so. They never add up parts into a rating of their own.

6 calculators

Guides for this topic

Questions people ask

What is the STC of a standard interior wall?
A single wood-stud wall with one layer of 1/2 in drywall each side and no insulation tests at about STC 33 to 35 in GA-600 listings. Adding fibreglass or mineral wool in the cavity raises it to roughly 36 to 39; a second layer of 5/8 in board on one side with insulation reaches the mid 40s.
Does a second layer of drywall help with noise?
Yes, by adding mass. Doubling the board on one side of an insulated wall typically adds 3 to 5 STC points; putting a damping compound such as Green Glue between the two layers adds several more, and the biggest jumps come from decoupling the sides with resilient channel, clips or staggered studs.
How many tubes of Green Glue do I need?
The manufacturer recommends two 28 oz tubes per 4 × 8 sheet for a standard application and three for a heavy one, so a 12 × 8 ft wall with 3 sheets takes 6 tubes, or one case of 12 for two such walls. The Green Glue calculator converts sheets or area into tubes, cases and the 5 gallon pails used on large jobs.
How much mass-loaded vinyl for a wall?
Mass-loaded vinyl comes in rolls, commonly 4 ft × 25 ft (100 sq ft) at 1 lb per sq ft. Measure the wall area, add about 5% for the overlaps and seams, and divide by the roll area; a 12 × 8 ft wall needs one roll, and the roll weighs 100 lb, so plan the lifting.
How many layers of drywall for a 1-hour fire rating?
The common 1-hour wood-stud wall in GA-600 is one layer of 5/8 in type X on each side with the fasteners at the listed spacing; a 2-hour wall takes two layers of 5/8 in type X each side. Insulation, screw pattern and joint treatment are part of the listing, so match the whole assembly, not just the board.

More calculator groups

  • Drywall sheets: How many sheets a room, a ceiling, a basement or a garage takes, which size to buy, and where moisture-resistant or fire-rated board belongs.
  • Screws, nails & adhesive: Screws and nails by sheet and spacing, adhesive tubes, furring strips and what an anchor will hold.
  • Mud, tape & corners: Compound by finish level, tape rolls, corner bead, skim coats, textures, sanding and mixing ratios.
  • Studs & framing: Studs, plates and blocking, metal framing, resilient channel, whole partition walls, rough openings and soffits.
  • Measuring & waste: Wall and ceiling areas, waste factors, sheet weights, thickness and orientation choices, vaulted ceilings and patch sizing.
  • Cost & hiring: Materials, hang-and-finish labour by level, removal, textures, repairs, DIY vs pro, time and whole-house budgets, with sourced ranges.
  • Planning & drying: Drying time by conditions, a project schedule with real dates, finish level choice, dumpster size, drywall vs plaster, and delivery and lift planning.

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