Attic Access

Technology Fact Sheet ATTIC ACCESS

For more information, contact: ATTIC KNEE WALL ATTIC ACCESS Energy Efficiency and Provide adequate insulation coverage and air sealing for the Renewable Energy Knee wall Desired Clearinghouse (EREC) ventilation access between living space and the unconditioned attic 1-800-DOE-3732 Attic Seal www.eren.doe.gov Seal living outlet space DON’T LEAVE A HOLE IN THE CEILING box to Attic space Hardboard Or visit the BTS Web site at drywall A home’s attic access, such as an attic hatch, SCUTTLE HOLE COVER www.eren.doe.gov/buildings Seal all edges of rigid Seal Insulation dams foam insulation pull-down stairs, or knee-wall door, often goes prevent loose-fill Or refer to the Builder’s Guide Attic ventilation uninsulated, representing one of the biggest insulation from Unwanted air leakage falling through Energy Efficient Building deficiencies in the thermal barrier between the access Hatch lid pushes up and Association, Inc. out of the way for access Buildings for attic and conditioned space. This gap in the 651-268-7585 The attic knee wall is often underinsulated and leaky. Install adequate insulation and air seal around the 21st Century attic insulation increases heat loss in winter www.eeba.org the living space for continuity in the building envelope when addressing the knee-wall door. Buildings that are more and heat gain in summer, and makes indoor Written and prepared for living areas uncomfortable. the U.S. Department of energy-efficient, comfortable, and affordable…that’s the Air seal Energy by: KNEE WALLS Such accesses are often not sealed properly. Tr im the sloped ceiling of the knee wall. The rafters goal of DOE’s Office of Building gasket Southface Energy Institute Another type of attic access is a knee-wall door. should be covered with a sealed air barrier, A ¼-inch gap around the perimeter of an Technology, State and 404-872-3549 A knee wall is typically a partial height wall that such as drywall, rigid insulation, or foil-faced attic access can potentially leak the same www.southface.org Community Programs (BTS). is usually found in the upstairs level of hardboard. One advantage of this approach is amount of air supplied by a typical bedroom To create the hatch, the installer should cut a To accelerate the development finished-attic homes. Knee walls are notoriously heating duct (~100 CFM). Unsealed, the attic plywood piece or save the ceiling drywall piece Oak Ridge that the storage area as well as any ductwork is and wide application of energy National Laboratory leaky and often poorly insulated. Make sure access in a home leaks energy dollars and now inside a more tempered space. efficiency measures, BTS: that is cut out for the hole. To ensure a tight Buildings Technology Center that the knee-wall door is weatherstripped and causes the house to be less comfortable. fit, securely fasten the trim around the hole to 423-574-5178 • Conducts R&D on technolo- has a latch that pulls it tightly against the frame the ceiling and make sure that it is flat and www.ornl.gov/ornl/btc KNEE-WALL DOOR gies and concepts for energy and weatherstripping to achieve a solid seal. level. An uneven base can cause air leakage. efficiency, working closely ATTIC ACCESS Use construction adhesive and screws to at- Weatherstripping can be installed either on the The Model Energy Code with the building industry tach rigid insulation to the attic side of the can be obtained from the and with manufacturers of hatch itself or on the inside of the trim or base International Code Council by door. Some attic doors are full-height interior materials, equipment, and where the hatch rests. Adding a latch bolt will calling 703-931-4533 doors which should be insulated, appliances help ensure a tighter seal. weatherstripped, and equipped with a tight MECcheck, a companion • Promotes energy/money An attic access After the trim or base is aligned to seal properly, compliance software threshold. saving opportunities to both is a big hole. Adding insulation should be added to the attic side of the package, can be ordered from Inspect the rest of the knee wall and adjust builders and buyers of homes DOE by calling an insulated cover and hatch. Rigid insulated sheathing is recom- 1-800-270-CODE insulation levels to meet those recommended and commercial buildings weatherstripping to an mended. Cut the insulated sheathing ¼ inch or downloaded directly in the 1995 MEC or DOE Insulation Fact Sheet. • Works with State and local access can reduce infiltration smaller than the hatch size to allow for clearance from the Web at If not enough insulation is installed, first air regulatory groups to improve when moving the access panel. Apply 3 or 4 inches www.energycodes.org/ and heat-loss through this seal the knee wall before insulating. Consider building codes, appliance resid/resid.htm. passageway. Latch bolts (not shown) may be of insulation to the hatch with construction adhesive covering the back of the vertical knee wall with standards, and guidelines for installed to help ensure an even tighter seal. and screws. As an added measure, glue the kraft- efficient energy use NOTICE: Neither the United rigid insulation. Insulated sheathing, with the paper side of batt insulation to the top of the last Add R-value to a knee-wall door by adhering States government nor any seams caulked or sealed with housewrap tape, • Provides support and grants ATTIC HATCH layer of rigid insulation. Try to achieve the same agency thereof, nor any of their reduces heat flow and minimizes the comfort rigid insulation boards (sandwiched together to States and communities hatch, total R-value as recommended by the 1995 Model employees, makes any warranty, One inexpensive and common type of attic with construction adhesive and screws) to the for deployment of energy- express or implied, or assumes problems commonly associated with drafty access is referred to as a scuttle hole or attic Energy Code (MEC)(see page 4) or DOE Insulation any legal liability or responsibility efficient technologies and attic knee walls. back of the door. Pay special attention to the which is simply a removable portion of Fact Sheet. Order the Insulation Fact Sheet (DOE/ for the accuracy, completeness, practices or usefulness of any information, In new construction, an improved approach is clearance between the insulation and the door the ceiling that allows entry to the attic above. CE-0180) from the Energy Efficiency and apparatus, product, or process to insulate and air seal the rafter space along frame and air sealing details. A scuttle hole is commonly located in a closet Renewable Energy Clearinghouse or access it disclosed. The views and opin- from the Internet at www.ornl.gov/roofs+walls. ions of authors expressed herein or main hallway. do not necessarily state or reflect Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 20% postconsumer waste. those of the United States gov- OFFICE OF BUILDING TECHNOLOGY, STATE AND COMMUNITY PROGRAMS February 2000 DOE/GO-102000-0768 ernment or any agency thereof. ENERGY EFFICIENCY AND RENEWABLE ENERGY • U.S. DEPARTMENT OF ENERGY ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

ATTIC ACCESS

ATTIC ACCESS LOCATION CONSTRUCT AN ATTIC STAIRS PULL-DOWN ATTIC STAIRS Location of an attic access is important. If possible, locate the COVER BOX ATTIC STAIRS COVER BOX

Insulation dams prevent Cover box pushes up access in an unconditioned part of the house (e.g., garage, Use the template shown here to cut ○○○○○○○○○○○○○○○○○○○○○○○○○○ loose-fill insulation from and out of the way for pieces from a single 4x8 foot sheet Pay careful attention to inside falling through access access covered patio, or porch) that is also secure against potential break-ins. A garage location, where the vented attic is of ½-inch rigid insulation for a box and outside dimensions plus uninsulated, can eliminate the need for sealing and insulation. 53½ inches long (51½ inches height requirements for the inside), 24¾ inches wide (22¾ specific measurements of the For a pull-down attic staircase, make sure that opening the stairs inches inside), and 9 inches high attic staircase being installed. will not interfere with the placement of furniture. The position Weatherstripping inside. This box will fit stairs with of the staircase in relation to ceiling joists might also affect The cover box should an outside framing dimension of Seal gap between rest squarely on top of location—placing the staircase between joists instead of across ceiling cover box frame and rough 53½ inches by 24¾ inches. Adjust joist sits on stairs frame opening with joists can speed installation because structural cross-member the attic stairs frame. caulk, backer rod, dimensions to fit the specific stairs or foam framing is not as complicated. Shim and seal the gap sealant Weatherstripping Panel being installed. Be sure to carefully weatherstripping between the frame andshim stairs frame measure both inside and outside ATTIC DECKING rough opening and Attic decking is often used to provide additional storage space or dimensions to the appropriate An attic stair cover box is made from rigid insulation. It drops install weatherstripping. a platform for an HVAC unit or hot water tank installed in the attic. length, width, and depth clearances down from the attic side to seal and insulate the pull-down The decking is often installed directly on top of the ceiling joists; for the cover box. stairs. this limits the amount of space available for insulation and lowers Create the box as shown: Apply the attic’s average R-value. adhesive/mastic and use roofing ATTIC STAIRS nails to construct the two end and Pull-down stairs are another common type of attic access. The To ensure proper insulation depth, the attic decking must be two side pieces. Assemble the side frame for the stairs fits in a rough opening and leaves a gap, raised above the ceiling joists. To accomplish this “edge-nail” 2x4’s or 2x6’s to the tops of the ceiling joists where the decking and end pieces into a box using much like that for a door or window, which must be sealed. If 22¾" 23¾" 24¾" adhesive and longer nails. Add the the gap is small (less than ½ inch), caulk can be used as the is to be located or, as an option for trusses, lag 2x4 members to 51½" center support brace and cover sealant. If a larger opening exists, then non-expanding foam or the truss webbing at the desired height. Install the decking 52½" Assemble side piece with glue and nails. A faced 53½" a backing material (backer rod) is recommended in conjunction securely to the top of the raised lumber after the insulation has pieces, end pieces, insulation batt may be glued to the with caulk. Expanding foam can be used, but care must be been installed. and brace as shown. cover piece with adhesive applied to taken because of its highly expansive nature; it could warp the The cover piece will the paper backing. frame and interfere with the ability of the stairs to open or close drop in and be at-

properly. To ensure a tight fit between the stairs’ flat panel and INCREASE ATTIC INSULATION LEVELS UNDER DECKING M ATERIALS NEEDED: tached with adhe-

9 END

• ½-inch rigid insulation 52½" 9 ½ ½ the frame, weatherstripping or gasket material should be added SIDE sive and nails. " " either to the frame or the panel. Latch bolts may be installed to For many products, an insulation depth of 10 to 14 • Insulation batt (optional) 24¾"

side 51½" 2½" help ensure a tighter seal. end inches is needed to achieve an R-30 to R-38 insulation • Duct sealing mastic or 2½" 9" 23¾" To insulate attic stairs access, a lightweight, moveable box can value. Thus, a 2x4 or 2x6 extension needs to be added to construction adhesive 52½" BRACE be constructed from rigid foam or fibrous ductboard to fit over a 2x6 joist to provide sufficient depth before installing 23

• 1-inch roofing nails (8d or ¾

COVER " the stairs from the attic side. Insulating kits are also available decking. 16d) through weatherization suppliers or from local hardware stores. 23¾" • Tape measure, sharp utility 9" As with all home projects, follow the attic stairs manufacturer’s 2½" end knife and straight-edge, or instructions for proper installation. Manufacturer’s guidelines often side 51½" 2½" table/circular saw 24¾" 9 2x4 9 ½ ½ " provide unique techniques and safety considerations for each SIDE END " • Weatherstripping/gasket particular unit. For safety and the extended life of the stairs, be sure 52½" 2x6 material with adhesive to cut the stairs to the proper length. This action will prevent strain on the hinges and reduce wear on the pivotal joints of the stairs. All pieces can be cut out of one 4'x8' sheet of rigid insulation. Use a table saw for smooth, accurate cuts.

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

ATTIC ACCESS

ATTIC ACCESS LOCATION CONSTRUCT AN ATTIC STAIRS PULL-DOWN ATTIC STAIRS Location of an attic access is important. If possible, locate the COVER BOX ATTIC STAIRS COVER BOX

properly. To ensure a tight fit between the stairs’ flat panel and INCREASE ATTIC INSULATION LEVELS UNDER DECKING M ATERIALS NEEDED: tached with adhe-

9 END

• 1-inch roofing nails (8d or ¾

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ Technology Fact Sheet ATTIC ACCESS