Insulating this space inside the knee wall improves the energy efficiency of the home and prevents heat transfer from the attic.
R value for attic knee wall.
This adds an additional r19 to the wall insulates all the studs to stop any thermal bridging and provides an airtight assembly.
Insulating the roof rather than knee walls and attic s floor while usually preferable is not a great option for this house for a number of reasons specific to this house.
According to a report by the washing state university extension energy program blown in fiberglass insulation provides an r value of between 2 2 and 2 7 per inch.
Walls are entered by the type of assembly and the r value of insulation.
If the existing attic floor insulation has an r 11 insulation value then an additional r 27 would be needed to bring the attic floor insulation up to the level recommended for that house.
So for instance i believe in my area zone 4 code would state you should r20 for walls and r49 for ceilings what would you believe the r value should be for knee walls using an insulation goal comparable to the goal the code sought.
1 use an r value map to determine the amount of insulation you need.
By adding an r19 to the existing r13 cavity insulation the knee wall assembly total r value is near r30 and is air tight.
Most computer programs allow the user to calculate gross wall areas and subtract window and door areas.
This knee wall has been encapsulated with 2 part closed cell spray foam.
We did it in one house but the customer was not as satisfied as i would like of course she was a little tougher than most customers.
With 2 layers between the joists and another layer running perpendicular over top the r value of the insulation in the side attic is in the range of r 40.
Superb thermo insulating parameters r value 5 2 along with high air tightness keep heat loss to a minimum.
The recommended r value for attic floor insulation for this house is r 38.
All r values are insulation only tested labeled per ftc rule16 cfr 460.
A 2 x 4 wall cavity with blown in fiberglass insulation will provide on average an r 13 to r 15 insulation value.
0 19 btu hft f loft ladder hatch u value 1 1 8 insulation thickness 5 2 attic ladder r value the knee wall access door dwk is intended to be built into l shaped walls.
A well insulated side attic.
Whether the attic access is an attic hatch pull down stairs or a knee wall door you should install insulation with the proper r value for your climate based on the department of energy s recommendations.
2 4 insulation has an r value of 13 5.
Also to find out where your home might be losing energy consider conducting an energy audit.
