How to Install a Window

8/2/2019 How to Install a Window

http://slidepdf.com/reader/full/how-to-install-a-window 1/6

iven the fact that win-dow ceate lage holein a houe’ exteio, I’malway hocked to ee

how many builde in ou aea don’tintall them coectly. In the nineyea that I’ve been building and

enovating home, I’ve een win-dow that haven’t been integatedwith the houewa, imoelyflahed intallation, and even win-dow with no flahing at all. Notonly doe imoe intallationaffect the duability and waanty of the window, but it alo exoe thewall cavity to moitue oblem.

Like any builde, my cew and Iwant to ue efficient actice thatwon’t negatively affect the quality of ou wok. Fo u, that mean uing

a agmatic aoach to intallingwindow with wot-cae cenaioand long-tem duability in mind.

wtr t b

Baed on conveation with ubcon-tacto and local building official,we’ve concluded that the eaonwindow aen’t intalled coectly

Doing everything

to ensure aleakproof job?If you don’t includethe housewrap,use a sill pan, andflash the flanges,the work is farfrom watertight.

BY ROB MOODY

Window Installation

Done Righ

G

FINE HOMEBUILDING54

COPYRIGHT 2008 by The Taunton Press, Inc. Copying and distribution of this article is not permitted.



HOUSEWRAPGETS A SPECIALCUT

Most buildersmake an X-cut inthe housewrap andstaple the resultingtabs into the open-ing prior to install-ing the window. Butfolding the top tabinto the openinggives water a wayin behind the win-dow’s top flange.Instead, cut a toptab that covers thewindow’s top flangeafter the window isinstalled (top pho-tos). Then add panflashing to collectand drain any waterthat does get in

(photos right).We make our panflashing on site withbeveled siding andself-adhesive flash-ing tape (below).We use Typar’s 9-in.wide Flashing Flex(www.typar.com) toflash 2x6 wallsbecause it allows usto form a seamlesspan that contours

to the sill. Otherbrands and widthsare also available.

pRepaRe The Rough opening wiTh housewRap and pan Flashing

First, cut across the header,then down the center.

Staple the tabs down,then cut the top tab.

Make a horizontal cut and two angled cuts to the sill.

Fold up the top tab, tape it out of the way

T t tb f , t

st- f

R- f

For us, making sill pans on site is efficient and cost effective. Butthere are manufactured pan-flashing systems available, such asDow’s Weathermate Sill Pan, shown here (www.dow.com; $5). Thiscan be an economical option if you don’t have a lot of windows toinstall. They come in various sizes to fit the opening’s width.

Beveled sidcreates a slsill. After wrping the opewe nail a pie

siding alongrough sill wi13 ⁄ 4-in. roofinnails. Be suradd the thicness of the sto the windoheight whening the rougopening. Seadhesive flatape goes oIn cold weatwe apply spadhesive (alscalled “prim

to improve ttape’s adhesThe Flashingtape we’re uhere calls foSuper 77 adWe run flashtape tight toinside of theing and 10 inup each trimstud, then fothe rest ovehousewrap. sometimes sthe corners

tape to prevthem from m

www.finehomebuilding.com poduct hoto thi age: Kyta s. Doefle AUGUsT/sEpTEMBEr 2008




often tem fom an unealiticexectation about the effective-ne of iding in keeing moi-tue out of the wall cavity. Whatmany window intalle don’tealize i that no matte howwell iding i intalled, moituefind it way between it and thehouewa.

When moitue end u ona laye a lick a houewa,it doe a logical thing: It lidedown the wall. Once that moi-tue eache the window, it ea-ily find it way into the oughoening though even the tiniethole. Moitue that leak into awall cavity caue mold to gow.Mold i bad, fo mateial andfo human. That’ why we doeveything we can to kee watemoving out and away fom the

window by integating it withthe houewa. R t ftrr’

Mot window manufactueecognize the diatou effectimoe intallation of theioduct can have on a home,including ignificant enegy lo.That’ why they ovide detailedintallation intuction fo theioduct. Following thee in-

tuction hel to kee the wallcavity dy and fulfill the win-dow manufactue’ waanty.

Although the hoto how mycew intalling metal-clad win-dow with integal flange, thete outlined hee offe a lookat fundamental element foundin mot manufactue’ intal-lation guideline. They addefoming the wateoof ill an,himming the window o thatit wok oely, and flahing

the flange to hed wate. Theete will eceive LEED ointa well.

In the ideba on . 59, con-tibuting edito (and coatalbuilde) Mike Guetin offeguidance on hanging two otheflange-tyle window, includingan aoach to flahing them

When installing large windows, remove thesashes to make the window easier to handleand to avoid obvious disasters like brokenglass. Achieving the perfect fit while workingwith only the window frame requires extracare, however. Without the sashes in place,the frame can rack and twist more easily. Keepthe nailing flange tight to the sheathing at alltimes, and run shims along the side jambsevery 8 in. to keep them square and straight.

T t t

bfr t

The bottom stays caulk-free. Run a 1 ⁄ 2 -in.-wide bead of caulk along the sides and top of the opening, but don’t caulk alongthe bottom. A sealed bottom flange cantrap water in the pan flashing. To comply with most window manufacturers’ warran-ties, be sure to use a window and door sili-cone caulk that has an ASTM C-920 ratingon the label.

Next, center the window in the roughopening so that there’s even shim spaceon each side of the jamb, and check thesill for level. If the sill is out of level, insert shims under one or both side jambs and inthe center of the sill to give it proper sup-port. When installing wider windows withmultiple units (double units, triple units),shim under each window’s side jambs and in the center of each window.

With the rough opening set, it’s time to install the window. Most manufacture

require the side and top flanges to be caulked to the perimeter of the roughopening. They illustrate adding the caulk to the flange, but we like to add it t

building instead so that it doesn’t get all over our hands as we put the windoRegardless, make sure there’s a good seal around the flange. Get the window

nailed off before the caulk dries.

caulk, shim, and nail The window in place

FINE HOMEBUILDING56




Nail the bottomflange only. Masure the windowis level, then nabottom flange e8 in. with 2-in. ring nails. We uspneumatic nailemetal-flanged wdows. The impaa nail gun can cvinyl easily, espin cold weathernails by hand, ogalvanized pan-screws when woing with vinyl-flwindows.

Plumb the jamdiagonal measuments off the jacorners to squaand plumb the j

shimming the ucorners as needThen hold the win place by nailithe two cornerstop flange fromoutside. Insert sand drive 2-in. fnails to straightside jambs.

Check the windfunction, then off the flange.only the top conailed and a few

ish nails in the s jambs, it’s easymake any necesadjustments to prove the windoperation. Oncwindow functioproperly, nail orest of the top side flanges eve4 in. to 6 in.

Eliminate draftspray foam. Insof stuffing fiber

insulation arounwindow, apply expanding sprafor the best air Backer rod can used to help filspace in deep wbefore the sprais applied.

www.finehomebuilding.com AUGUsT/sEpTEMBEr 2008




Extra protection for the head jamb. The head jamb is the most-vulnerablepart of the window, which is why these windows come with a drip capthat adds a layer of protection. A

similar cap can be made with flash-ing tape and aluminum coil stock (sidebar facing page).

The sides run long. Run flashingtape 4 in. to 5 in. past the top and bottom flanges. Make sure the topsof the side pieces stay at least 1 in.short of the top of the head piece(photo right) so that the head piece

will have a good, continuous bond with the sheathing. For windowswith integral flanges, like the oneswe’re installing here, butt the tapetight to the jamb.

lap The Tape shingle sTyleSelf-adhesive flashing tapes generally break down into two types: asphalt-

and butyl-based. Asphalt-based tape can damage certain types of vinyl, socheck the window’s specs before using it. Butyl tape is easier to work with.

It doesn’t have an aggressive initial tack, but its adhesiveness increases overtime. When possible, we use tapes made by the manufacturer of the house-

wrap we’re using because the products are designed to work together.

Tape the top. Roll tape over the top flange, let-ting it run past the side pieces by 2 in. to 3 in.Once the top piece is in place, fold down thehousewrap tab. Tape along the bottom of theflap and at the corners with housewrap tape.Leave the bottom flange tape-free. The window is now ready for casing and siding.

FINE HOMEBUILDING58




that goe beyond manufacbaic. We figue that oan and flahing aoacabout 10 minute to the intion time fo each windoan aveage of $15 in mateeach double-hung unit. elatively chea inuanuch a lage invetment.

w

Thee day, evey houeflahing-tae, and wimanufactue ha a ecifiintallation guideline thabe followed to uhold eaective oduct’ waanwhat do you do when thetadict one anothe?

We follow Mike Guetivice and ue the mot-eotocol. Fo intance,

the window manufachow no flahing detafollow the tae o houintuction. When oneintuction call fo a flat ill an and anothe ca loed an, ceate a loeIt’ unlikely omeone wilyou didn’t follow the intuby doing moe than i call

When in doubt, thouglow the window manufacintuction. The Int

tional reidential Code (r equi e windo w “intalled and flahed accto manufactue’ intucIf thee’ eve a oblem, done what wa equiedbuilding code.

Rob Moody is president

The EcoBuilders in Ashe

N.C. Paul Bobbitt, the c

pany’s building-science

cialist and project mana

contributed to this articPhotos by Chris Ermides

except where noted.

Mechanical flanges fit into grooves around the

window jamb. They rely on a r ibbed spline tostay engaged in the groove. The spline and a

narrow gasket work together to keep out

water. Hinge-style flanges are shipped folded

against the frame, which leaves the corners

incomplete. Manufacturers supply metal or

plastic corner pieces to be applied and caulked

once the window is hung (photo below).

Nonhinged-style flanges overlap to form the

flange corner. One benefit of mechanical

flanges is that if they

become damaged dur-

ing installation, they

are easy to replace.

You install them by

tapping a wood blockalong the inside tab

(photo top right). The

downside is that they

can become disen-

gaged after installation

for a variety of reasons

(for example, the

siding installer pushes

or bumps the jamb,

or someone steps on the sill before it’s

shimmed in place).

To reduce the chance of window leaks, I

make sure that everyone who works around

them is aware of damage areas. I also shim

around the window jamb’s perimeter every6 in. and screw through the jamb and shims

into the framing. Finally, (1) I lap the flash-

ing tape about 1 ⁄ 4 in. onto the side jambs and

then over the flange and housewrap. At the

window head, (2) I run the tape over the jamb

and down onto the window face by 1 ⁄ 8 in. to1 ⁄ 4 in. I then install metal cap flashing over the

head-flashing tape (3) to conceal the tape.

Not all flanged windows are made the same. The windows shown in this article have an integral nail-

ing flange, which means that the flange is part of the window’s exterior cladding. Integral flanges are

a good design because there aren’t seams or joints for water to sneak past. Hinged and nonhinged

mechanical (also called applied) flanges are also found on vinyl and metal-clad windows. Although

these flange styles aren’t inferior to integral flanges, they have a few vulnerable areas that require

extra attention during installation. —Mike Guertin is a contributing editor.

Mechanicalflanges requireextra attention

Hinged Nonhinged

By Mike Guertin

Hinged

Look for the Magazine Extras section on our hpage to learn about flashing a window’s heading and to see another method of sill-pan flas

FineHomebuilding.com

1 2

3

www.finehomebuilding.com AUGUsT/sEpTEMBEr 2008

COPYRIGHT 2008 by The Taunton Press Inc Copying and distribution of this article is not permitted

How to Install a Window

Documents

Transcript of How to Install a Window