How To Flash A Flangeless Window

Synopsis: Flangeless windows, ofttimes referred to every bit "Euro-style windows," take different installation details than the flanged windows common in the United States. In this commodity, builder and remodeler Jake Bruton details a Flangeless window installation: locating the window in the opening, flashing the rough opening, setting and securing the window, and so face up-sealing for water and moisture command.

Some of yous may have taken the time to picket my video series with Fine Homebuilding about properly installing flanged windows in multiple assemblies. Those methods utilise to most windows installed in the Us, only they don't utilise to flangeless "European style" windows, including the triple-glazed, tilt/turn windows preferred by many high-performance builders. This blazon of install is known equally a "face-sealed organization".

Of course, some of the central principles are the same; shingle-style lapping, for example, is the correct fashion to detail whatsoever window flashing, besides as using a back dam and creating a slope at the sill of the rough opening. Your walls may vary, only these principles will provide a solid starting bespeak so that you tin adjust the installation to conform your state of affairs. The windows on the projection shown here are from Schüco, though many European-way windows install similarly.

Locating the window in the opening

Over the past v years I have not congenital a home with walls that were less than 71⁄ii in. thick. Almost of the time that assembly includes 2×six framing (five1⁄two in.) plus i⁄2 in. of drywall within and 11⁄2 in. of Zip System R-capsule outside. Having this thick wall gives united states an opportunity to make choices about how our Euro-style, flangeless windows are installed.

One choice is to push the window outward in the associates, but this presents more challenges for h2o direction because the window is closer to the weather. Moving the unit to the interior face of the wall improve protects the unit from the elements, only in doing so, also moves the unit away from the sunlight and the breeze—ii reasons why nosotros accept windows in our houses in the first place.

The other gene that must exist considered when positioning a window unit of measurement is the potential for creating a microclimate. If the window is placed all the manner to one side within a deep wall (in this case, likely deeper than 71⁄2 in.), you limit airflow in the window well on the opposite side, and this raises the take chances of creating a zone that is different than the surrounding areas. This microclimate can create the correct conditions for moisture accumulation in areas where you don't want information technology. For this reason, I typically locate the window in the heart.

This limits the microclimate effect and maximizes the connectedness to the light, breeze, and views, all while limiting the window'south exposure to the elements—by which I hateful primarily water, mostly in the form of rain.

Moving the window head into the middle of the wall is essentially like placing it under a small roof, limiting exposure to water. The top corners of windows are the most mutual places for leaks—but if information technology doesn't get wet, and so information technology tin can't leak.

Preparing the crude opening

We add materials to the rough opening that the manufactures oasis't factored into their recommended rough-opening dimensions, and that means I demand to frame our openings a little bigger than the standard. The dimensions for your chore will vary depending on your specific associates. To do this efficiently and minimize room for error, I discover information technology helpful to use a spreadsheet, set so that I can enter
the window size and utilise a formula to calculate our framed rough-opening dimensions.

If our budget allows, I wrap the rough opening with 7⁄16-in. Zero Organisation sheathing to create a durable, easily executed connection betwixt the exterior air bulwark and the rough opening. This is the almost of import takeaway from window installation: The water barriers and air barriers must fully connect to each other. I adopt to use Zip Arrangement sheathing in the opening, especially when using Naught R-sheathing on the exterior, because it protects the exposed foam edge around the opening—but if the budget is more restrictive, like on this dwelling house, this same protection can be achieved using tape.

I use a rip of 3⁄four-in. stock to create a dorsum dam on the rough sill, placed directly beneath the window, 2-1⁄ii in. from the face up of the sheathing. In front of the dam I place a rip of cedar bevel siding to create a gradient toward the exterior of the wall to encourage any water that gets behind the flashing to drain to the exterior. When you rip the cedar siding to width, always utilize the thickest edge, which provides better withdrawal resistance when nailed into place with short covering nails. After our sill pan is congenital, the waterproofing process begins.

Time to start flashing

When dealing with multiple planes and angles, a fluid-practical flashing is best. It tin can be pushed and dragged into nooks and crannies with ease. Just needing to mask things off and wait on dry out times means a stretchy flashing tape is a faster and more upkeep-friendly way to get. And so, when the budget doesn't permit for a fluid-applied product, Zip System stretch tape is our selection. When using tape, be careful to protect it while the windows are being placed. A sharp window corner resting on the wrong plane during installation can cut holes in the tape.

As with most exterior assemblies, the waterproofing starts at the bottom of the rough opening and continues upwards shingle-style. The first piece of stretch tape is cut roughly 12 in. longer than the width of the sill. I similar to marking a centerline on both the bottom of the sill and the tape and so I tin can align them easily. With the stretch tape, showtime in the center of the opening in order to ameliorate control how the tape is stretching to both sides. The stretch tape should lap about 1 in. or so onto the back dam, wrap across the width of the cedar siding fastened to the crude sill, and turn downward and out onto the water-resistive bulwark (WRB), which in this example is the Zero System R-capsule.

When it comes to the vertical legs of the installation, I employ ii runs of Nothing System seam tape. I prefer to apply the 4-in. product because I already have the tape on-site for sheathing installation, wider tape is harder to get in my area, and I like the control you lot can become with the narrow backer-free tape. Starting on the jamb side, the offset row of tape sits entirely in the rough opening and is pressed mainly on the crude-opening framing. The second row of tape rests about i in. into the opening and then turns onto the confront of the WRB, creating a durable connection (run into photos, p. 59).

I treat the head a little differently than the sill—at the sill I'm very concerned most having joints that could fail, so I use one slice of stretch tape across the entire assembly. The caput of the rough opening is much more protected, then I'm comfy with joints in that location. I similar to cut 2 12-in. pieces of the stretch record to particular each corner, and so I apply two runs of the four-in. seam tape as I did on the jamb sides.

Once all this tape is applied, it is adhered with a hard-rubber roller in social club to wet the tape in place. Recall, these tapes take a force per unit area-activated glue, and I can't stress enough the importance of this step.

Time to install the window

With the rough opening flashed, I place a couple small scraps of 7⁄16-in. sheathing at the outside edges of the sill, confronting the jamb sides. These trivial pieces allow me to check the sill for level and shim every bit needed, and then I tin can residual the window on superlative without fear of puncturing the flashing.

To ease installation, I employ a trick borrowed from installing prehung, solid-jamb doors. Instead of attempting to agree the window in place inside the crude opening, I depict a plumb line upwardly from the confront of the back dam, which I know is where I desire the face of the window to exist, and mount temporary boards to create a terminate. And so, when I elevator the window into the opening from inside the house, I tin can but push it tight to these temporary stops and it will be plumb. I fasten these boards with screws held close to the window so that, when removed, the screw holes will be covered past our concluding window tape.

The rough opening is now prepped and ready to accept a window unit of measurement. Depending on whether the Euro-mode window is a fixed or operable unit, it will install with simply metal clips or both clips and screws. The clips are fastened to the UPVC frame on-site, and I put i half-dozen in. from each corner, and then spaced less than 2 ft. in between those on all sides of the frame. Here's a helpful tip: When mounting the clips to the jamb, curve the prune toward the window unit earlier angle the prune toward the jamb. The 2 bends together give the clip an get-go that will aid it lay apartment after the screws are in place (meet drawing, p. lx).

After the units are all hung from the clips, so-called "turbo screws"—fully threaded, roughly 3⁄xvi-in.-dia. by 6-in.-long screws—are driven through the interior window jambs into the rough opening through factory-drilled holes. The idea behind using a fully threaded screw is that the unit doesn't have to be shimmed side to side because the threads grab the crude framing and window frame, locking everything into place. Later on testing the window to make certain it is functioning properly and making any needed adjustments, it'southward time for the terminal taping.

Face-sealed details

The record I use for the face of the window is Siga's Fentrim. Information technology'due south about three in. wide, has a fold with a i⁄2-in. face that doesn't have backing, and has a split backing on the residual of the width. This partial-backing design is helpful when applying the record, but information technology can be difficult to cut with a knife. I have institute that the best method for cut the pieces I need is to use a big worktable and pair of scissors. To make up one's mind the length of each slice, I measure the edge of the window I'm taping and then add ane in.

To install it, I align the tape so that the backer-free one⁄2-in. face laps onto the window and then press it firmly into place. This allows the bankroll on the residuum of the tape to be removed fairly easily by a single installer. Fair warning, though: This Siga tape has a very loftier initial grab, so it's still finicky to work with. As usual, the sill is taped earlier the jamb sides and the pinnacle is taped last. Once all the tape is practical, I seal the corners, the well-nigh vulnerable expanse, with a bead of fluid-applied sealant.

I know some of you simply panicked at the thought of taping the sill, which is ofttimes left open for drainage. I assure you, this is not the worst idea ever—I desire the record at the sill for air-sealing. While leaving the bottom of flanged windows open is considered best practice, when it comes to a Euro-style, flangeless window protected past the jamb at the head, I accept much less concern about leaks. That said, part of the reason for choosing the Fentrim record is that it's vapor-open, which means that if water does become behind the window, it volition have an opportunity to dry. For this to piece of work, it's important that when you add a bead of spray cream around the interior side of the window, you take care to not fill by half the depth of the jamb. This leaves a void behind the Fentrim tape, and the sloped sill keeps the water from seeping inward until information technology has a chance to dry out to the exterior.

In short, there is no reason to be afraid of European-way flangeless windows. All it takes is a few minor adjustments to your current methods to have a properly water-managed assembly.

Wink The Opening

Discourage water entry at the sill Use a piece of iii⁄4-in. stock to create a back dam and a rip of beveled siding to create a pitch toward the outside border of the sill.	Utilize stretch tape On the rough-opening sill, lap one continuous piece of stretch tape over the beveled siding and onto the dorsum dam, extending about vi in. upwards the sides of the rough opening.

Piece of work your way up . For the sides and top of the opening, I use two parallel, overlapped rows of 4-in. seam record, which is more readily available in my surface area than wider rolls. The sequence is sides, then upper corners (which are less vulnerable to water and can be sealed with short pieces of flexible flashing), then across the acme. After all the record is in identify, press every square inch using a hard-rubber roller.

Set The Window In The Opening

create a gap for insulation, nail small scraps of sheathing to the top of the back dam, giving the window a place to sit.

Permanent blocks, temporary stops.

To protect the sill flashing tape from damage and create a gap for insulation, smash small scraps of sheathing to the top of the back dam, giving the window a identify to sit. And then add temporary stops to the sides of the rough opening to locate the window during installation.

Practice the twist . The metallic installation clips, which are attached to the window on-site, lock into the edge of the window frame with a twisting motion.

A preparatory bend To go the installation clips to sit nicely against the rough opening, first curve them toward the window, and then dorsum toward the rough opening, creating an start.

use vacuum cups that attach to the glass.

Get a grip European-manner triple-pane windows are heavy, then to protect your fingers and brand lifting and moving easier, use vacuum cups that attach to the glass. Nosotros use cups from Wood's Powr-Grip, which sell for nearly $eighty apiece.

adjust the window side to side as needed until the reveal is even

Centered and plumb . Prior to fastening, adapt the window side to side as needed until the reveal is even, and verify that information technology'due south plumb.

Secure The Window In Place

Two screws will practice . First, screw the clip to the inside of the rough opening, and and so bend it around the face up of the framing and drive another screw.

No shims needed
For operable windows, fully-threaded "turbo screws" provided by the window manufacturer lock the frame in identify, eliminating the need for shims.

Face up-Seal The Window

One backing at a time . Siga Fentrim flashing tape has a thin, unbacked lip and
a split backing, then you lot tin can adhere the lip to the window first and then each half of the wider, backed leg to the sill one at a time for more command. Apply the unbacked lip to the window frame first, then adhere the remaining tape to the back dam and sloped sill.

Apply the same Fentrim tape up the rough-opening sides

As always, proceed shingle-style . Utilise the same Fentrim tape upwardly the rough-opening sides, so across the acme, then that each layer laps over the previous layer, and then whorl all of the tape.

seal the corners with a bead of fluid-applied flashing

A fluid insurance policy . To give the transition between sill and jamb side added protection, I like to seal the corners with a bead of fluid-applied flashing, which I smooth with a quick swipe of my finger.

From FineHomebuilding #292

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More near window flashing:

Don't Forget the Flashing – Hands overlooked and sometimes installed incorrectly, flashing keeps water out and rot at bay.

Flashing for Old Windows – How do you go a proficient weathertight seal on old windows that don't have a flange?

Fix for Poorly Installed Window Flashing – When water is leaking in around newly installed windows, chances are that there are some missing or improper flashing details that demand to exist corrected.