Attic Insulation. Student Guide

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1 Basic Weatherization - Conservation Measures & Efficiency Student Guide

2 Basic Weatherization - Conservation Measures & Efficiency Student Outline 1. Introduction [1] 2. Purpose of Insulation [1] a. R-value [1] b. Insulation R-values [1, Table 1] 3. Insulation Materials [2] a. Fiberglass [2, Picture 1] b. Cellulose [2, Picture 2] c. Recycled cotton fiber [2, Picture 4] d. Vermiculite [2, Picture 3] 4. Attic Preparation [3] 5. Installing Insulation in an Attic [4] a. Calculation of R-value of existing insulation [4] b. Calculation of the amount of insulation to achieve R-value [4] c. Calculation of amount of insulation to be added to existing insulation [5] 6. Non Feasibility [5]

3 Basic Weatherization - Conservation Measures & Efficiency INTRODUCTION Insulation is the most recognizable weatherization measure. Insulation, especially attic insulation, is associated with energy saving. It is the simplest to understand but one of the more complicated weatherization measures to install. The installation of attic insulation involves great preparation and care. Before we can look over installation, we need to review the priciples, consideration and characteristics of common insulation materials. PURPOSE OF INSULATION Insulation is a material that slows down the movement of heat through walls and ceilings, stops heat conduction and convection through wall cavities. Most common insulation materials work through stoping convection currents in walls and attics. The materials trap air and control the heat transfer. Common insulaton materials include fiberglass, cellulose, closed cell foam, expanded polystyrene, and even recycled cotton. Vermiculite, rock wool, and perilite have also been used as insulation materials. Insulation materials are designed to slow down the heat flow from conditioned space to unconditioned space. In order for it to work properly, air barriers, vapor barriers, and ventilation must be properly installed. The most common types of insulation materials are fiberglass and cellulose. Insulation is classified as flexible or loose fill. The flexible material is usually fiberglass batts or blankets. Loose fill is usually fiberglass and cellulose. Each type has different purposes and different strengths and weaknesses. All insulation is rated by R-value. R-value is the measure of how well a material resists heat flow. The higher the R-value, the better the insulation qualities of the material. So a R-19 insulation is better than a R-13 insulation. R-values of the same material increase with the material thickness. Material R-value/inch Fiberglass batt 3.0 Fiberglass blown 2.5 Cellulose blown-attic 3.5 Spray foam 6.5 Table 1: Insulation per inch R-values [1]

INSULATION MATERIALS Fiberglass insulation is the most common material for new and retrofit construction. It comes in batts, blankets and loose fill.

Batt and blanket insulation come in rolls or stacks, sometimes with paper, plastic, or foil facing as a vapor barrier. The vapor barrier or faced side should face the conditioned space.

4 INSULATION MATERIALS Fiberglass insulation is the most common material for new and retrofit construction. It comes in batts, blankets and loose fill. It is made of spun glass fibers that trap air in the spaces and stop the heat transfer by stopping air movement. Batt and blanket insulation come in rolls or stacks, sometimes with paper, plastic, or foil facing as a vapor barrier. The vapor barrier or faced side should face the conditioned space. Conditioned space is the warm winter side, or the side of the wall that is heated or cooled. Insulation is recognizable by color, including pink, yellow, or white, depending on the manufacturer. Picture1: Fiberglass batt with craft paper Cellulose is an insulation material that has been in use for a long time. It is made primarily from recycled newspaper with a fire retardant. It can be used for walls as well as attics. For weatherization purposes in our area, its primary use is as attic insulation. Cellulose has a higher R-value than fiberglass and has good air sealing properties. It does settle and does not work well when wet. Sprayed in place foam is used to seal large cracks and small openings inside a structure. Either polyurethane or latex, it comes in expanding and minimally expanding types. The polyurethane will stick to most things and requires solvent clean up. Latex is easier to clean up but not as sticky. Entire rooms and buildings can be insulated and sealed with spray foam, using two part foam, coming from two different cans mixed at the gun. For weatherization purposes, the one part foam in small cans is used for sealing and insulating small areas. Picture 2: Loose fill cellulose Another insulation material is recycled cotton fiber. This insulation is made from recycled pre-consumer fabric (denim from the manufacture of blue jeans). It is treated and made into batts and blankets. It does not irritate the skin like fiberglass or put off dust during installation. It is more expensive than fiberglass batts and not as readily available at this time. In the past other materials have been used for insulation but are not in wide use today. Among these are rock wool, vermiculate, perlite, and mineral wool. Even though these materials are not in great use today, it is important to be able to recognize them. The most important material to recognize is vermiculite. Vermiculite is a mineral mined from the ground. It looks like small eraser sized rocks. It is light and was poured into attics. Some of the mines used for the vermiculite mining contained asbestos. If you find [2]

The attic must meet safety and health standards as well as have the correct barriers for attic items. The attic must be structurally sound and have adequate space before it can be insulated.

5 vermiculite in the attic, do not disturb it and check with the supervisor before installing insulation. Picture 3: Vermiculite insulation Picture 4: Cotton fiber insulation Attic Preparation Before an attic can be insulated, special preparations must be made. The attic must meet safety and health standards as well as have the correct barriers for attic items. The attic must be structurally sound and have adequate space before it can be insulated. There must not be any spaces that are inaccessible or too small for a person to reach. Ceilings where the joists are too far apart or too small to support the weight of the installer, cannot be insulated. If there are exposed wires, open electrical boxes, knob and tube wiring it is unsafe to install insulation. Another thing to look for is a vapor barrier in the attic. If the vapor barrier is correctly installed, facing the living space, then insulation can be added to the current insulation. If the vapor barrier is installed incorrectly, it must be removed or slashed to allow air flow. Attic ventilation is another important characteristic to determine the feasibility of attic insulation. The size, arrangement, and location of the vents in an attic determine the feasibility of installing insulation. You will perform the calculation for attic venting later on. If the venting of an attic is not sufficient to allow insulation, additional venting can be added to the attic. Once the attic is safe for insulation, barriers must be placed around the areas that are not to be insulated. Attic vents, combustion air intakes, and heat producing devices (HPD) must be blocked off from insulation. We use batts that are thicker than the insulation that will be installed in the attic. For example, if we are to insulate the attic to R-19 or about 6 of loose fill cellulose, we would use an R-30 fiberglass batt to act as a barrier around a HPD. Exhaust [3]

6 vents for furnaces, kitchen exhausts and recessed can lights are considered HPDs. The insulation must be kept 3 from an HPD. We can also use sheet metal for barriers. Metal barriers must be kept 4 above the insulation and still maintain 3 of clearance. If you use a piece of fiberglass batt for a barrier, make sure that the batt piece is at least 14 ½ long, and extend 14 ½ in every direction. For attic vents, cardboard or metal chutes may be used as barriers to hold insulation the correct distance from the vent. Also consider the attic access door. It must be weatherstripped and insulated, to R-19, if it is between conditioned and unconditioned space. For complete standards and specifications for insulation, refer to the WIS manual, Section 3. Another part of an attic to consider, are knee walls. Knee walls are small walls that extend from the ceiling joists to the roof rafters to divide the space and or support the roof. The function of the knee wall is important to determine if it should be insulated. If the knee wall is between conditioned and unconditioned space, and over 12 high, it must be insulated. The installation of knee wall insulation is done during the attic prep stage. In the WIS Installation Standards Manual, you will also find information on combustion appliances in the attic. Most new construction and a lot of retrofit installation will locate the furnace in the attic. The standards are different than for HPD s, and are determined by the orientation of the flame and firebox. Check the installation standards to find the correct way to form barriers around a combustion appliance. Installing Insulation in an Attic The first step to installing insulation in an attic is to determine how much insulation is needed in the attic. The existing insulation and what is the desired R-value are considerations for attic insulation. There are three basic insulation calculations: Calculation of R-Value of existing insulation Calculation of the amount of insulation necessary to achieve a desired R-value Calculation of the amount of additional insulation to be added to an attic with existing insulation. Here are the steps for each of the calculations. I. Calculation of R-Value of existing insulation: 1. Determine the type of existing insulation 2. Find the R-value per inch for existing insulation 3. Measure the depth of the existing insulation 4. Calculate the R-value R-value (existing) X R-value/inch = Existing R-value II. Calculation of the amount of insulation to achieve R-value: 1. Determine the insulation type 2. Determine the R-value per inch of the insulation 3. Calculate the depth of insulation required [4]

7 Desired R-value R-Value per inch = inches of insulation 4. Determine the amount of insulation needed for the job Area of attic area coverage per bag = number of bags (use manufacturer s coverage table) III. Calculation of amount of insulation to be added to existing insulation in an attic: 1. Calculate the R-value of the existing insulation (use instructions in Part I) 2. Find the added R-value Desired R-value existing R-value = added R-value 3. Use coverage charts to determine the amount of insulation required to raise the R-value Once the attic insulation requirements have been calculated, it is time now to prep the attic for installation. Start with the sealing of air leaks and gaps in the attic. All necessary barriers must be installed and necessary clearances maintained. Have a plan for installation. Start from the farthest point from the opening. Also do hard to reach and places first. Make sure to have a gauge for the required thickness. This could be the top of the floor joists or cardboard rulers stapled to the joists. Hold the hose horizontally and start the machine. Another technique is to lay the hose flat on the ceiling and pull the hose toward you as the insulation is filling. Follow all standards from the WIS installation manual. Non feasibility Below is a list of conditions that will prevent attic insulation Joist spaced more than 24 apart Less than 24 space under the ridge of the roof Open electrical boxes (cover plates may be installed) Evidence of vermin Roof leaks Inadequate venting Presence of knob and tube wiring Customer refuses [5]

8 Basic Weatherization Conservation Measures & Efficiency Student Note Sheet 1. Purpose and function of insulation 2. Materials of insulation 3. Types of insulation Loose Batt 4. R Knee wall 6. HPD 7. Non-feasibility

Basic Weatherization Conservation Measures & Efficiency Calculation Activity Name 1. Determine the amount of insulation needed to insulate the attic below with loose fill fiberglass to R- 19.

9 Basic Weatherization Conservation Measures & Efficiency Calculation Activity Name 1. Determine the amount of insulation needed to insulate the attic below with loose fill fiberglass to R- 19. (Use instruction sheet and table sheet for information needed to solve problems 1-3) Answer Table 1 Insulation Type Loose Fiberglass 2 R-value/inch 3 Area of attic 4 R-value 5 Depth (inch) 6 # of bags

10 2. How much additional thickness of insulation needs to be added to the existing attic to reach R-30 if the existing insulation is 3 ½ of cellulose? Answer Table 1 Insulation Type Loose Cellulose 2 R-value/inch 3 Added depth (inch) 4 R-value (existing) 5 R-value additional

3. What is the amount of insulation (cellulose) that needs to be added to the existing attic to reach R-19 if the existing insulation is 3 ½ of cellulose?

11 3. What is the amount of insulation (cellulose) that needs to be added to the existing attic to reach R-19 if the existing insulation is 3 ½ of cellulose? Answer Table 1 Insulation Type Loose Cellulose 2 R-value/inch 3 Added depth (inch) 4 R-value (existing) 5 R-value additional 6 Area of attic 7 # of bags

12 Basic Weatherization Conservation Measures & Efficiency Insulation Calculation Instructions There are three basic insulation calculations: Calculation of R-value of existing insulation Calculation of the amount of insulation necessary to achieve a desired R-value. Calculation of the amount of additional insulation to be added to an existing attic with insulation. I. Calculation of R-value of existing insulation 1. Determine the type of existing insulation 2. Find the R-value per inch for existing insulation 3. Measure the depth of the existing insulation 4. Calculate the R-value R-value (existing) X R-value/inch= Existing R-value II. Calculation of the amount of insulation to achieve R-value 1. Determine the insulation type 2. Determine the R-value per inch of the insulation 3. Calculate the depth of insulation required Desired R-value R-value per inch = inches of insulation 4. Determine the amount of insulation needed for the job Area of attic Area coverage per bag = number of bags (use manufacturer s coverage table) III. Calculation of amount of insulation to be added to existing insulation in an attic 1. Calculate the R-value of the existing Insulation (use instructions in Part I) 2. Find the added R-value Desired R-value Existing R-value = added R-value 3. Use coverage chart to determine the amount of insulation required to raise the R-value

13 Basic Weatherization Conservation Measures & Efficiency R-value Table Material R/Inch R/Thickness Insulation Materials Fiberglass Batt 3.14 Fiberglass Blown (attic) 2.20 Fiberglass Blown (wall) 3.20 Rock Wool Batt 3.14 Rock Wool Blown (attic) 3.10 Rock Wool Blown (wall) 3.03 Cellulose Blown (attic) 3.13 Cellulose Blown (wall) 3.70 Vermiculite 2.13 Air-entrained Concrete 3.90 Urea terpolymer foam 4.48 Rigid Fiberglass (> 4lb/ft3) 4.00 Expanded Polystyrene (beadboard) 4.00 Extruded Polystyrene 5.00 Polyurethane (foamed-in-place) 6.25 Polyisocyanurate (foil-faced) 7.20 Construction Materials Concrete Block 4" 0.80 Concrete Block 8" 1.11 Concrete Block 12" 1.28 Brick 4" Common 0.80 Brick 4" Face 0.44 Poured Concrete 0.08 Soft Wood Lumber " Nominal (1 1/2") x4 (3 1/2") x6 (5 1/2") 6.88 Cedar Logs and Lumber 1.33 Sheathing Materials Plywood /4" /8" /2" /8" /4" 0.94 Fiberboard /2" /32" 2.06 Fiberglass (3/4") 3.00 (1") 4.00 (1 1/2") 6.00 [1]

14 Material R/Inch R/Thickness Extruded Polystyrene (3/4") 3.75 (1") 5.00 (1 1/2") 7.50 Foil-faced Polyisocyanurate (3/4") 5.40 (1") 7.20 (1 1/2") Siding Materials Hardboard (1/2") 0.34 Plywood (5/8") 0.77 (3/4") 0.93 Wood Bevel Lapped 0.80 Aluminum, Steel, Vinyl (hollow backed) 0.61 (w/ 1/2" Insulating board) 1.80 Brick 4" 0.44 [2]

15 Basic Weatherization Conservation Measures & Efficiency Attic Preparation Activity Name Activity Description: Identify the areas in the attic that will require blocking. Install required blocking including fiberglass batt and sheet metal barriers. Installation will include batt insulation for eve vents, sheet metal HPD, R-30 batt HPD, and plastic or cardboard eave vent chute. Identify Attic Conditions Attic Condition Barrier Solutions Complete Installation of Barriers Barrier Installation 1 HPD blocking with R-30 2 Eave vent blocking with R-19 batt 3 HPD with metal flashing 4 Eave vent with chute 5 Other: 6 Other: 7 Other: 8 Other: 9 Other: Completion

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