Retrofit Insulated Wall & Roof Panel Installation Guide

the window surface and its perimeter. When a WRB is installed atthe existing window and sheathing plane it is intended to act as asecondary barrier and drain at the window and bottom of the wall.Structure AssessmentThe first step in an energy retrofit is assessing the existing structure.Retrofit insulated panels can be installed over most types of woodframe residential and block structures after the existing siding orroofing has been removed. Keep in mind that retrofit panels willincrease the thickness of the wall or roof by the dimension of thepanel’s thickness. Existing roof overhangs should be greater thanthe added thickness of the wall, or provisions should be madefor extending overhangs.Consider whether doors and windows will be replaced with theretrofit. Develop an access plan for later removal andreplacement without damaging the retrofit panel installation ifthe windows and doors will be left in place for the currentproject. Windows that are left in place after installation ofretrofit insulated panels require complex details and dualdrainage planes to assure bulk water resistance at the opening.Windows with installation flanges should always be installed onthe outer face of the retrofit panels.Other special features like dormers, roof brackets or corbels,exposed rafter tails, and cantilevers or bays may require specialaccommodation by a design professional. Begin with a sketch ofthe exterior of the house, include door and window openings,and outside dimensions.Key MeasurementsMeasure the wall and roof area to determine the squarefootage and layout of retrofit panels that will be required.Retrofit insulated panels are a frequently-employed solution foradding insulation to vaulted ceilings or incorporating atticswithin a home’s conditioned space. For conventional ventedattics, retrofit insulated panels are often applied to the walls, only,Figure 2. Retrofit Insulated Panel Installation Detailat Outside Corner4Retrofit Insulated Panel Use Guide

while bulk insulation and air sealing is added to the attic to improvewhole house thermal performance.When measuring the wall area, it is important to note that panelswill extend beyond the existing wall dimensions at corners by thethickness of the retrofit panel and the product should be orderedaccordingly (Figure 2). Panels are non-structural, so they can bepieced together to accommodate maximum material usage.However, the reliability of the air seal and labor time management,as well as the use of optional accessory materials like splines,sealant, and spray polyurethane foam (SPF), encourage the use ofcomplete panels whenever possible.Figure 3. Retrofit Insulated Panel Extended Over Rim JoistRetrofit Insulated Panel Installation Guide5

Figure 4. Alternate Retrofit Insulated Panel Rim Joist DetailIf installing retrofit insulated panels as shown in Figure 3, the panelshould be located at least 8 inches above grade, as with any woodproduct.AccessoriesInstalling retrofit insulated panels requires the use of severalspecialty accessories. These may be included with the retrofitinsulated panel package or it may be the responsibility of theinstaller to purchase the appropriate accessories prior toinstallation. The manufacturer of the retrofit insulated panel canprovide information on the correct sealants and fasteners to usewith their products.Common accessories include:6Retrofit Insulated Panel Use Guide

Sealant – caulking used to seal between retrofit insulatedpanels that does not react with insulating foamPanel screws –screws used to attach retrofit panels tostructural members through the thickness of the panelSplines – optional strips of OSB, pre-manufactured insulatedblocks, or dimensional lumber used to join two retrofitpanels together that may be specified by the designprofessionalStorage OnsiteRetrofit insulated panels should be protected from the elements onthe jobsite. Panels should be stacked on a level surface and elevatedoff the ground on dunnage or stickers made of dimensional lumber.When stacking panels, the bottom panel needs to have firm contacton all pieces of dunnage and the dunnage needs to be wide enoughthat it will not deform the bottom panel. Panels should be stackedOSB side down and at a limited height to keep the dunnage fromdeforming the panels. To protect from rain and UV exposure,opaque tarps or a roofed shelter is recommended.InstallationInside corners are a good place to start retrofit panelinstallation. Inside corners are installed using a buttjoint and optional sealant per the design professional’srecommendations (Figure 5).If there are no inside corners on the structure start thelayout on the longest wall at the outside corner. Workacross the wall and from bottom to the top of thehouse, continuously. Walls are typically installed with atwo-person team, dependent on overall wall height.Figure 5. Inside Corner Detail.Table 4 covers the estimated weight of retrofit panels.Retrofit Insulated Panel Installation Guide7

Table 4. Estimated Retrofit Insulated Panel WeightEstimated RetrofitInsulated Panel Weight(lbs. per panel)PanelThickness4"6"7 ¾”9 ¾”11 ¾”4' x 8'57646672794' x 10'72808390984' x 12'8696991081184' x 16'115128132143157When a window ordoor opening in thewall is encountered,install the panel thatprecedes the panelwith the cut out,then measure for thecut out. Cut the OSBwith a circular sawthen use a hot knifeto remove the EPS ata work station. Sizethe opening and theEPS cut toaccommodate thedesired windowdetail; i.e., OSBoverlapping orFigure 6. Wall Retrofit Insulated Panelsbutting the windowbox. Place the sealant per the design professional’srecommendations and install the panel.FastenersRetrofit panels are installed with screw connections driven throughthe retrofit panel into the structural members of the existing housewall or roof. Panel fastening schedules vary with weight of thecladding to be installed. Typical fastening patterns range from 12"8Retrofit Insulated Panel Use Guide

to 24" with studs spaced at 24" o.c., but actual fastening patternswill be supplied by the design professional. Panel screws arecommonly supplied with the retrofit panel package.Wall claddings are attached to the OSB skin of the retrofit panelwith nails or screws as per the siding manufacturer’s installationdirectives. HardiePlank fiber cement lap siding has issued aTechnical Bulletin covering attachment of their products to 7/16"OSB sheathing. Table 5 covers an abbreviated version of a TechnicalBulletin for fastener spacing and type, wind speed zones, andfastening location for 5 ¼" wide fiber cement siding. The Referencessection contains a web link to the complete bulletin.Table 5. Example of a Manufacturer’s Fastening Schedulefor Horizontal Lap Fiber Cement to OSB SheathingExcerpt from Technical Bulletin Fastening JamesHardie Products over SIPs and retrofitinsulated panels. Exposure categories as per IRC 2009.Sidings of similar weight and size will have similar fasteningconstraints. Table 6 covers the weight of a few of the more popularwall claddings.Table 6. Average Weight of Wall Cladding MaterialsRetrofit Insulated Panel Installation Guide9

Type of CladdingCedar, 5/8" bevel stk.Fiber Cement, 5/8" smooth lapVinyl, double 4.5, .040”Weight Per Square Foot(lbs.)3.0B2.3C0.4AA c%20Vinyl%20Siding.pdfB www.csgnetwork.com/lumberweight.htmlc www.jameshardie.com/homeowner/products siding hardieplankLapSiding.py?search zipcode retailSolid lumber blocking is often required to attach heavier items likehand rails or awnings. Lumber blocking should be sized the width ofthe foam and slightly larger than the object that needs to befastened to it.Roof claddings are attached to the OSB skin of the retrofit panel perthe roofing manufacturers’ fastening installation instructions. In aconventional roof assembly, many of the fastener connections aremade through OSB rather than as a fastener embedment in astructural member, thus there is nothing new about fasteningcomposition shingles to a retrofit roof panel. Make certain to reviewmanufacturer’s guidelines with regard to roof pitch and nailingpatterns. Consult product manufacturers about fastening specialtyroofing finishes.Adhesives and SealantsIf sealants are used during retrofit insulated panel installation, thesealants need to be EPS compatible. These products are oftensupplied by the retrofit insulated panel manufacturer and can beused for foam to foam, wood to foam, or wood to woodconnections. Common solvent-based construction adhesives are notcompatible with EPS foam and should not be used where they arelikely to come in contact with the EPS.Another commonly used product is low-expansion, closed cell, spraypolyurethane foam. Unlike sealant, spray polyurethane foam can beused to seal gaps or voids. It is recommended that all sealants andadhesives used with retrofit panels be low VOC products.10Retrofit Insulated Panel Use Guide

Windows & Door Installation Using New UnitsInstalling retrofit insulated panels adds to the wall thickness, thus,new windows will be mounted flush with the OSB surface of theretrofit panel. A new construction, flanged, window, or pre-hungdoor, with exterior molding attached to the jamb will be installedflush with the OSB surface of the retrofit panel. Jamb extensions arefashioned with dimensional wood that matches the thickness of thefoam in the retrofit panel. Jamb extensions are attached with longscrews through the depth of the new dimensional lumber memberinto the existing studs at the window opening and caulked at thebuilding and the existingsheathing. Adhesive caulkis installed on the outsideedge of the jambextensions to adhere tothe back of the OSB ofthe retrofit panel if theEPS foam at the windowopening in the retrofitpanel was routed out 1Figure 7. Retrofit Panel Routed for Window Box½" from the panel edgeCourtesy Zero-EnergyPlans.comprior to panel installation(Figure 7). It is ofteneasier to install thedimensional lumber afterthe panel has beeninstalled.Otherwise, the windowopening can be cut intothe retrofit panel so thatthe foam and the OSB ofthe retrofit panel butts tothe window box extension. Spray polyurethane foam completespanel-to-panel and foam-to-window box connections.Figure 8. Window Box with Retrofit PanelCourtesy Zero-EnergyPlans.comRetrofit Insulated Panel Installation Guide11

Homes with older, sash-type windows may need to have the roughopening enlarged by cutting back sheathing to expose and removesash weights (Figure 10). In this case, a larger window is orderedand mounted on the outside as described above. Windows andFigure 9. Window Mounted at Exterior Planedoors are installed after the WRB has been installed and taped andflashed consistent with the window manufacturer’s instructions andASTM 2112 (References section). Mounting an exterior window ordoor will require jamb extensions on the interior of the house.Interior jamb extensions can be fashioned from painted drywall ortrim material and fastened to the material that is used to create thewindow box12Retrofit Insulated Panel Use Guide

If a larger window isdesired, cut backexterior sheathing andinterior plaster to exposesash weight cavity.Order replacementwindow to fit largeropening. Use retrofitpanel cut to square upexisting opening. Makenew opening same sizeor smaller than existingrough framing. Staywithin existing headerwidth.Figure 10. Replacing Sash-Type WindowsInstallation with Existing WindowsWhen the decision to keep the existing windows is made, theexisting windows should be removed and remounted at exterior ofthe retrofit insulated panel using the process described above fornew windows (Figure 11).If the home contains older sash-type wood-frame windows thatcannot easily be removed and reinstalled, they can be left in placeand jamb extensions can be installed on the exterior toaccommodate the thickness of the retrofit insulated panels (Figure12).Retrofit Insulated Panel Installation Guide13

Figure 11. Windows Left in PlaceFigure 12. Alternate Window Box MountCourtesy: Cold Climate Housing Research Center14Provisions for futurewindow replacementwithout compromisingthe air seal of the retrofitpanel installation mustalso be made. Strip theexisting window trim todetermine the type ofwindow mount. Verifythat head and sideflashing and sill pan arerepelling water and thatarea around windowshows no sign of waterintrusion. (If there iswater intrusion and thewindow must beremoved to repair,consider remounting it atthe outside face of theretrofit panels.) Once thewindow is well flashedRetrofit Insulated Panel Use Guide

and sealed, install the new window/jamb extensions wide of thewindow flanges or jamb edge so that the window unit can bereached and removed at a later time without damage to thewindow box. The construction of the window box can be made ofany number of materials, which are dependent on future windowinstallation location and aesthetics. If the intention is to remount afuture replacement window inside the wall, the jamb extensions canbe formed in aluminum coil stock or other light gauge metal asflashing and the finish trim. This type of trim can be installed afterthe retrofit panel and should include a continuous downwardsloped sill.In Figure 12, the window box has been created with a 1" x 8" trimboard of cellular PVC. The box is supported by a steel L bracket onall four sides. To make the window accessible for a futurereplacement, size the box wide of the window flange and seal thewindow box to the retrofit panel with spray polyurethane foam(SPF). Trim inside window box at window frame with custom coilstock as required.Mechanical Penetrations through the ExteriorWallAny plumbing or electrical penetrations through the buildingenclosure will also require extensions to account for the additionalwall thickness. Wall mounted light fixtures will need to be removedand remounted after the retrofit panels are installed. Electricalwiring to exterior fixtures may need to be lengthened toaccommodate the added width of the retrofit insulated panels. TheOSB facing eliminates the need for light blocks where the fixturesare attached to the wall.Retrofit Insulated Panel Installation Guide15

Roof Retrofit Insulated Roof PanelsFigure 13. Roof Retrofit Panels Applied to Structural MembersRetrofit insulated roof panels are attached through the width of the

Retrofit insulated panels can be installed over most types of wood-frame residential and block structures after the existing siding or roofing has been removed. Keep in mind that retrofit panels will increase the thickness of the wall or roof by the dimension of the panel's thickness. Existing roof overhangs should be greater than