Attic Insulation 2x4 Rafters

Ceiling joists are the horizontal boards that span the width of the house resting on the outer wall plates and possibly on.

Attic insulation 2x4 rafters.

Get a free 24 hour blown in machine. Box out light fixtures. Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be. They are directly below the roof sheathing and are were insulated with fiberglass batts stapled between the 2x4 rafters.

This over rafter insulation method also reduces thermal bridging giving an airtight continuous layer of high performance insulation and results in a well insulated attic space. I would really like to get more than r 13 and the current installation is probably providing r 1 with all the missing pieces. For roofs that will experience heavy snow or wind and will span the same distance use 2 6 rafters. How to increase the interior ceiling joist for r38 insulation.

You get a free blown in machine rental with your insulation purchase. Water is insulation s enemy. For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters. You can use either 2 6 or 2 4 rafters for roofs with a 3 12 pitch or greater but it depends on the overall size of your shed.

Shaded or north facing roof pitches would be the most susceptible but with only 2x4 rafters and likely r13 or less the roof deck runs warmer drier than if it were insulated to current code min. For instance if the roof has 2 by 6 rafters and you want r 30 insulation which is standard in many communities you can add a 2 by 4 which will give you an 9 inch rafter space. By installing high density 8 inch fiberglass batt insulation the rafters will then meet an r 30 roof insulation standard. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.

It makes adding insulation to your attic a breeze. Insulating the roof above the rafters is known as warm roof insulation as the rafters are brought into the insulated envelope of the building.