WEB BASEDAPPLICATION SPECIFIC INSTALLATION INSTRUCTIONS

Installing Curvedand Angled Windows

Although all possible measures have been taken to insure the accuracy of the material presented, WIXSYS, and the author are not liable and do not assume any liability in case

of misinterpretation of directions, misapplication, improper installation, or typographical error.

Installing Curved and Angled Windows

Vinyl Windows are made in more than just rectangu-lar configuration. There are many choices of architec-tural shapes - round, half-round, quarter-round,ovals, hexagons, octagons, trapezoids, and triangles.In fact, almost any shape can be ordered. These oddshapes can add design flexibility to a replacement orremodeling project, and they are especially usefulbecause they can fit into the most unlikely placessuch as cramped stairwells and shallow attics. Thesewindow types generally don’t have operating sashand they do not provide ventilation, but besides thedecorative addition they make when used in combi-nation with other windows, these special shapes,when used alone, can provide light in dark places,and their shapes will also add charm or traditionalelegance.

Because they are shaped differently than rectangularwindows, special architectural shapes require somemodification to standard installation instructions.

The following tips and illustrations are meant asguides to determine the best way to proceed. Onceyou have decided on the type of shape you want, con-sult your dealer or manufacturer for specific recom-mendations and available options for installation.

Installing Special Shapes

Special Shapes can be installed in two basic ways. Ifthese shapes are ordered with a conventional double-hung, slider, or casement/awning type window, itmay be possible to install them mulled together withthe rectangular window.

Header

King Stud

Jack Stud Shim

AngledSupport

The Illustrated Guide to Installing Vinyl Windows Contents © 2004-14 Do not reproduce without permission

WIXSYS Online Window Installation Resource © 2015 AWDI, LLC Do not reproduce without permission

If the special shape is ordered to be installed alone,then modified, conventional framing methods need tobe used.

Because of the variety of shapes that are possible,standardized instructions are not really possible, orpractical to follow.

Circular windows are braced differently than ovalwindows, and angular windows are braced a thirdway. In fact, the only basic, common feature withspecial shapes is the need for jamb extensions to fitthem to the interior wall.

If these extensions must be cut from wallboard orwood it will require more skill than most amateurshave.

The good news is that some manufacturers makepre-formed jamb extensions that snap-in to thegroove provided for the snap-in mull strips.

Using a hair dryer to warm the vinyl, this extensionsystem can be bent to accommodate curved windowsas well.

1. Special shapes, whether mulled or separate, mustbe installed in a clear opening with the old window(sash and frame) completely removed.

2. Integral fin should be used on special shapes as anailing anchor and to create a self-flashing installa-tion.

3. All windows, rectangular, curved, or otherwiserequire a proper sized header above the window tosupport the studs above.

4. All odd-shaped windows require similar studdingto a conventional rectangular window opening.

5. A Drip Cap, formed by shaping aluminum or vinyl J-channel (fan-cut for curved windows) should beinstalled above all windows over proper flashing.

Flashing Curved Windows

Step 1

Step 2

Step 3

Step 4

Take care that thesheathing is appliedwith the correct arcand that the propersupport for the curvedwindow is in place.

Too often it is cut orformed haphazardlyand the resulting gapsinvite leaks no matterhow well the openingis flashed.

Place the window inthe opening. Nail justenough to anchor it tothe opening, but nottoo much to deformthe nailing fin andallow the window toslightly expand andcontract.

Do not nail across thebottom.

Cut three pieces offlashing and applythem in overlappingsequence over thenailing flange.

Apply top piece last.

Use flexible uPVC or carefully notch alu-minum to make a dripcap if needed.

Just as you would ina rectangular open-ing, the sill flashing isapplied across thebottom and slightlyup the sides. Makesure it extends pastthe sides of the open-ing.

Place a bead of caulkon the sheathing orbehind the nailingflange.

Caulk across the bot-tom leaving two gapsfor drainage.

No Shrinkage

Locks out air and water infiltration to protectintegrity of the seal

Proven Wet Surface Application

Ability to use the same sealant in warm and cold temperature situations to produceconsistent results. 0F – 140F cold and warmweather application

Strong Adhesion / All Surfaces Will stick toeven the most difficult to bond buildingmaterials

5X stretch, 50% joint movement Long termdurability assurance even with expansionand contraction of building materials

24 hour fast cure, paintable 1 HR. Fast cureto protect the building structure from outsideforces and quick paintability saves time

Achieves bubbling resistance faster to ensureoptimal aesthetics

4,600 + Color Matches ensures perfect colormatch to all primary building materials

Dirt & Dust Resistance ensures optimal visual appeal long after an installation

UV Resistance

Long term durability to compliment the durability of the building structure

••

••

•

•

•

•

•

•

••

DYNAFLEX® from DAP asa good representative toseal the exterior joints ofwindows and exterior fin-ish materials. The bestchoice is a sealant thatmeets AAMA 800-802 toassure proper adhesion tothe most common buildingmaterials and that is com-patible with WRB andflashing tapes; and can beued in a wide temperaturerange and wet surfaces.

AWDI understands that the application of a sealant isas crucial as the choice of sealant. When a bead ofsealant is applied to a joint there are severable factors to consider:• Adhesion• Flexibility• Durability

Within these three performance aspects there arecountless combinations of applications, substratesand conditions a sealant is exposed to.

Bedding Joints: For bedding joints, it is especially important that the sealant meet AAMA 800-802, and is of the rightconsistency and made up of 100%solids so it will not shrink after cure,unlike solvent and latex basedsealants that shrink and creategaps after curing.

Fillet Joints: A fillet joint is formed when two surfaces cometogether to form a right angle. The sealant used tojoin these two surfaces is tri-angular in shape. Thesealant must adhere to thevariety of substrates you’refaced with. Without strongadhesion there is a highchance that the sealant willpull away from the substrateallowing for air and waterinfiltration.

Control Joints:A control joint is formed when two similar or dissimilar materials meet or when substrates do not form a right angle. This jointwill require both a backer rod and sealant for properapplication. This joint can be as wide as 5/8 inchand be prone to extreme movement, a highly flexiblesealant is necessary for a reliable seal with thisapplication. In order to successfully install a win-dow or door and effect alasting weathertight seal,AWDI recommends anASTM C920, Class 50sealant such as premium

Picking the Proper Sealant

Desired Properties

The Contractors Guide to Installing Windows © 2014-18 AWDI, LLC Do not reproduce without permission

BOND BREAKER

TAPE

ANGLED JOINT

BACKER ROD

• Compatibility• Temp, Weather, Exposure)• Aesthetics

While the term “Spray Foam” is often widely used inconstruction, there are two different types and eachhas its advantages and disadvantage.

Spray foam has been shunned by window installersand manufacturers over the years because foams, inthe past, have either continued to expand after trimhas been applied deforming the more pliable vinylwindow frames, or because they have been over usedto fill the gaps left when old windows are removedand the underlying rough opening has been exposed.

Make sure the foam you use has been tested inaccordance with AAMA 812 and meets standard forlow pressure development.

Most standards applying to window installation donot delineate between open cell foam and closed cell foam, the more popular “minimal expansion”foams are most frequently used and they are mostlyclosed cell. More confusing yet, is when foams arerecommended, the compressed foam tape alternativesare called out to be open cell.

When it comes to Spray Foams, it helps to under-stand the differences.Open-cell spray foam (ocSPF)has a cell structure where the cells are filled with air.The open-cell structure renders soft, flexible foam,with a density of about 0.5-0.8 pounds per cubic foot(pcf).

The R-value per inch of open-cell foam typicallyranges from R3.6 to R4.5 per inch. Unlike fiberglassand cellulose, the fine cell structure of ocSPF makesit air-impermeable at certain thicknesses. The air-impermeability of ocSPF qualifies it as an air-barriermaterial, dramatically reducing air leakage throughthe building envelope, significantly lowering thebuilding’s heating and cooling costs. However, ocSPF, like fiberglass and cellulose insulations, is moisture-permeable, and may require the installa-tion of a vapor retarder in colder climates.

Closed-cell spray foam (ccSPF) has a closed cellstructure which yields rigid hard foam, with a

density of 1.8-2.3 pound per cubic foot (pcf), and can provide structural enhancement in certainframed buildings. The smaller cells trap insulatinggas from the curing, which has a lower thermal conductivity than still air, and increases the R-valueto anywhere from R5.8 to R6.9 per inch.

Like ocSPF, ccSPF is also air impermeable at certainthicknesses and can qualify as an air-barrier materi-al. The bigger benefit is that the closed-cell structureof ccSPF also makes it water-resistant, and is theonly spray foam that can be used where contact withwater is likely.

At a thickness of 1.5 inches, no additional vaporretarder is required for most applications.

Spray Foam Insulation

The Contractors Guide to Installing Windows © 2014-18 AWDI, LLC Do not reproduce without permission

Make sure the foam used has been tested inaccordance with AAMA 812 and meets stan-dard for low pressure development.

Quick Setting Formulation: can be cut ortrimmed in less than 1 hour

Cold Temperature Application: can beapplied in temperatures as low as 14F

Insulation Value of R5: makes it an efficientmethod for stopping air and moisture infil-tration

Remains Flexible Once Cured: will not crackor dry out

•

•

•

•

•

Desired Properties

Using Spray FoamFor the best installation, it is necessary for the gaparound the window or door to be sealed to block outair, water and vapor penetration. ccSPF can do thatwell if selected and used properly. Improper use cancreate water traps, impede drainage and exert exces-sive pressure to the window frame during expansion.

Remember: Vapor barriers need to applied on thewarm side of the opening. Double vapor barriers (one on the warm side and another on the cool side)encourage condensation between and will trap theresulting condensation. Also, window installationcavities (the space between the window frame and the rough opening, or left-in-place old window frame)need to “breathe” to the outside, and allow drainageof collected water to the outside.

Used wisely, ccSPF can be the best solution. AWDIrecommends DAP® DRAFTSTOP 812 Window andDoor foam. DAP® DRAFTSTOP 812 also achieves athermal performance of R-5 per inch.

ApplicationDAP DRAFTSTOP Foam is applied using a FoamApplicator Gun. This foam and gun combinationallows for more precise application than the strawgrade foam alternative. This gun offers a rear valveused to control the size of bead applied into the open-ings. The valve also allows the life of the foam to beextended by closing the opening of the barrel forfuture use.

For even smaller openings, a detachable screw on topis included with the gun to be able to fill gaps assmall as ¼” wide.

The Contractors Guide to Installing Windows © 2014-18 AWDI, LLC Do not reproduce without permission

Important tips:• Similar to the sealant gun, it is critical that you balance the movement of the foam gun or straw barrel and how you dispense the foam so that thefoam makes contact with both the rough or existingwindow frame and replacement window frame.

• If the dispensed foam does not make contact withboth the rough frame and the window frame, therewon’t be an adequate bond to seal out water and air.

• Industry Standards suggest application of 1 inchbeads, separated by an equal space. Be careful not to create two vapor barriers - one at the exterior andone at the interior. Make sure there is the ability forthe opening to breathe to the cold side for drying anddrainage. Use backer rod about one inch in the sill asa stop to make a workable back dam

• When applying foam around the perimeter of the window or door, you must maintain a minimumdepth of 1 inch. This depth is required to provide the correct thermal performance, to help improveenergy savings, and to protect against condensationproblems.

• When applying foam as a back dam to the gapbetween the window frame and the rough sill, do not allow the foam to extend to the exterior edge ofthe opening. Maintain a minimum of a 1 inch gapbetween the foam and the exterior edge of the roughsill. If foam fills this gap at the sill, any water fromleakage will not be able to drain to the drainage planeor exterior cladding surface. Place backer rod thelength of the sill, 1” from edge and use it as a backdam guide.

Backer Rod

1”Set Back

FoamBead

FoamBead