®

PROJECT PLAN

How to build a Cupola

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CupolaCupolawWhen I decided to build a cupola to dress up my bland garage, I began by taking a walk.

Most of the cupolas in my neighborhood are purely decorative. But the really old ones—

those that sit atop garages that were once carriage houses—were built for both decoration

and ventilation. In the days before roof and ridge vents, a cupola was the most effective way

to ventilate a stable, barn or even a house.

Old or new, most of the cupolas I saw had some peeling paint or rotting wood. There

were two typical trouble spots: the “saddle,” the part of the cupola that sits directly on the

roof, and the “sill,” which rests on the saddle. To make my saddle maintenance-free, I

wrapped it in aluminum flashing (Photo 14). To avoid problems at the sill, I beveled mine

and left no flat areas where water could stand (Photo 1). I also used vinyl brick mold, rather

than wood, to frame the vents.

56 JULY / AUGUST 1999 THE FAMILY HANDYMAN

Decoration, Ventilation and a Hangout

HOW TO BUILD A

by Mac Wentz

for Your Rooster.

polapolaA

CUT-OFFS

CEDAR2x6

1x6

SILLPARTS

FENCE

3/4"

WARNING: GUARD MUST BE REMOVED FOR THIS PROCEDURE. USE CAUTION!

This article will show youhow to build and install acupola with these mainte-nance-saving features. Thecupola’s structure is fairlysimple, and all the dimen-sions, curves and angles areprovided. The curved“witch’s hat” roof may looklike the work of a master car-penter, but the entire cupolais an intermediate-level project. In fact, a novice withjust a little carpentry experi-ence can do a satisfactory job.After all, minor mistakeswon’t be visible from theground. But you will needseveral power tools (table saw,jigsaw, circular saw, drill androuter) and at least three fulldays to build this cupola. NOTE: A cupola mounted on agarage or shed will keep thebuilding cooler in hot weatherand drier during damp sea-sons. But for your home’sattic, a cupola alone doesn’tprovide adequate ventilation:By itself, it doesn’t let enoughair escape, nor does it providea place for air to enter theattic. For effective ventilation,install soffit vents along withroof or ridge vents. (See “Howa House Works,” Nov. ’97, p. 96. To order, see p. 112).

PLYWOODSCRAPS

FRAMINGSQUARE

SOFFITPARTS

SILL

SILL

CEDARCORNER POST

BEVEL 2x6s on a table saw.To cut the pieces that willform the sill of the cupola,bolt a 1x6 to the saw’s fence(to keep the workpiece fromtilting), set the blade at 19degrees and position thefence 3/4 in. from the blade.To bevel the soffit parts, setthe blade at 45 degrees andthe fence 4-1/4 in. from theblade. To make bevel cut-ting easier, we first cut 2x6sinto 30-in. sections. Whenall eight pieces are beveled,sand them and then miterthe ends at 45 degrees. Savethe beveled cut-offs fromthe sill and rip about 1/4 in.off them. You’ll use themlater to complete the slopeof the sill (Photo 4).

ASSEMBLE the sill andsoffit frames by screwingtemporary plywood scrapsto the undersides of the2x6s. Don’t cover up thecorners—you’ll need todrive screws through themlater. And make sure thatthe sill and soffit frames areperfectly square.

THEN SCREW the sill tothe corner posts. Drill pilotholes and drive four 3-in.screws into each post, twoon each side of the miterjoint. The inner edge ofeach post should meet theinside corner of the sill.

1

2

3

WARNING: GUARD MUST BE REMOVED FOR THIS PROCEDURE. USE CAUTION!

Start with the Vent Housing

58 JULY / AUGUST 1999

THE FAMILY HANDYMAN JULY / AUGUST 1999 59

BASIC MATERIALSYou’ll spend about $150 tobuild this cupola, less thanhalf the cost of a similar man-ufactured model. Most homecenters and lumberyardscarry everything you need.Here’s your shopping list:n One 8-ft. cedar 4x4 (actualsize is 3-1/2 x 3-1/2 in.)n Three 10-ft. cedar 2x6sn One 8-ft. 2x2 (1-1/2 x 1-1/2 in.)n One 4x8 sheet of 3/8-in.plywoodn One 4x8 sheet of 3/4-in.pressure-treated plywoodn Four 8-ft. pieces of brickmold. Vinyl brick mold ismaintenance-free, but it holdspaint poorly and is usuallyavailable only in white. If youwant a different color, you’llhave to use wood brick mold. n Four 12 x 12-in. vinyl oraluminum gable vents. Thedimensions refer to the lou-vered area, not the vent’sframe. Our 12 x 12-in. ventsmeasured 14-1/2 x 14-3/4 in.Metal vents, which are usuallywhite, can be spray painted.For a lasting paint job, lightlysand the vents with 220-gritsandpaper first. n One bundle of shingles.Home centers usually stock afew common colors and canspecial-order many others. n One 10-ft. long roll of alu-minum flashing. Paintedflashing usually comes withone side white, the other darkbrown. But you can lightlysand and spray paint it afterit’s applied to the saddle. Thewidth of the flashing you needdepends on the pitch of yourroof; the steeper your roof,the longer the sides of the sad-dle (Fig. A, p. 64).

VINYLBRICK MOLD

CUT-OFFS

SILL

COUNTERSINKBIT

ASSEMBLE brickmold frames betweenthe posts. Predrill andcountersink the holesbefore driving screws.You may have to drawthe posts together orspread them apart tomake the top piece ofbrick mold fit. Screwthe bottom and sidesof the frames to theposts and screw thetop piece to the sides.Remember to fastenthe beveled cut-offs tothe sill with nails andconstruction adhesivebefore you install thebrick mold. Fig. A onp. 64 shows thedetails.

SOFFIT

BRICK MOLDFRAME

VENT

SCREW the vents tothe backsides of thebrick mold frameswith 1/2-in. self-tap-ping sheet metalscrews. Then attachthe soffit to the cornerposts just as youattached the sill.

H O W T O B U I L D A C U P O L A

4

5

n Galvanized screws (1-1/4, 2 and 3 in.), 1/2-in.self-tapping sheet metalscrews, 1-in. galvanized nails,3/4-in. roofing nails, con-struction adhesive, acryliccaulk, roof cement (twotubes).

BUILD THE VENTHOUSING FIRSTFig. A on p. 64 gives all thedimensions you’ll need to cutthe parts for the housing. Photos 1 – 5 show how it allgoes together. Here are somepointers to help you along: n Unless you have a radialarm saw or sliding miter saw,use a circular saw to miter theends of the 2x6s that make upthe sill and soffit. A circularsaw isn’t the best tool formaking perfect miters, butsmall imperfections won’t bevisible from the ground. n We cut coves into three cor-ners of each 4x4 post (Photo

3) using a 1/2-in. radius coverouter bit ($16 from TrendLines; 800-767-9999; ItemCT1025K). n Use a couple of pieces ofduct tape to hold each vent inplace as you drive screwsthrough the vent’s frame andinto the brick mold. To saveyourself the trouble of drillingpilot holes, use self-tappingscrews. n Fill the cracks in the sill andsoffit and seal around the

BARCLAMP

PLASTICDOORSTOP

35DEGREES

1-1/2"

CENTER OFRAFTER

PROTRACTOR

55DEGREES

MARK and cut one rafter,then use it as a template tomark the other three. Tomark the curve, we put asection of plastic door stopmolding in a bar clamp andtightened the clamp untilthe curve was right. Anythin piece of wood willwork, but we used plasticbecause it doesn’t haveknots or any other imperfec-tions that lead to an incon-sistent arch. Use a protrac-tor ($5 at home centers) tomark the correct angles atthe ends of the rafters.

JOIN the rafters using a 6-1/2 in. piece of 2x2 as ahub. Screw the hub to twoof the rafters, and fasten theother two by driving 3-in.screws through the raftersinto the hub. Center therafter assembly on a 26 x 26-in. piece of 3/8-in. plywoodand drive 1-1/4 in. screwsfrom below through the ply-wood and into the lowerend of each rafter. Cut ahole in the plywood base sothe roof can dry out if watergets in.

3/8"PLYWOOD

GRAIN RUNSHORIZONTALLY

GAP

FASTEN the 3/8-in. plywoodto the rafters with 1-1/4 in.screws. Begin at the middle,driving the screws at anangle. There should be a gap(about 1/2 in. wide) betweenthe pieces of sheathing. Whenthe sheathing is done, centerthe roof on the vent housingand drive four screws upthrough the soffit into theroof’s base. You can removethe roof later to make it easierto carry. Important: Be sure tocut the roof sheathing so thatthe grain runs horizontallyacross each piece. Plywoodbends more easily across thegrain than with the grain.

3/8"PLYWOODBASE

2x2HUB

Build the ’Witch’s Cap’ Roof

6

7

8

THE FAMILY HANDYMAN JULY / AUGUST 1999 63

64 JULY / AUGUST 1999 THE FAMILY HANDYMAN

3/8" PLYWOOD ROOF SHEATHING (SEE PATTERN)

3/8" x 26" x 26" PLYWOOD BASE

2x6 RAFTER (SEE PATTERN)

2x2 HUB, 6-1/2" LONG

4x4 POST, 17" LONG

12" DIA. HOLE

2x6 SOFFIT, 28" x 28" OVERALL

2x6 SILL, 28" x 28" OVERALL

LOUVERED VENT

1-1/4" x 2" VINYL BRICK MOLD, 17" x 17" OVERALL (13" x 13" OPENING)

1-1/4"

2"

1/4"

1-1/4"

8" TO 16" (DEPENDS ON ROOF PITCH)

4" MIN.

FLASHING TABS

2x2 CLEAT, 24-1/2" LONG

ALUMINUM FLASHING; WRAP SADDLE AND BEND OVER TOP AND BOTTOM EDGES

2x2 ROOF CLEAT

3/4" PRESSURE-TREATED PLYWOOD SADDLE, 26" x 26" OVERALL

CUT

9"5"

14"

1-1/2"21"

35° 5-1/2"

55° CUT FROM 2x6

3/4"

18-3/4"

26"

CUT FROM 3/8" PLYWOOD

BEVELED SILL CUT-OFF

CL45° MITER (TYP.)

2" OVER- LAP

PEAK FLASHING

ASPHALT SHINGLES

HUB

RAFTER

BASE SOFFIT

2-1/2"

2-1/2"

1/2" RAD. COVE IN POST

SILL

CAULK

CLEAT

CLEATSADDLE

CUT-OFF

BRICK MOLD

3-1/2"

POST

ROOF PANEL

Fig. A Cupola Details

H O W T O B U I L D A C U P O L AS

ad

dle

Ven

t H

ou

sin

gR

oo

f

JULY / AUGUST 1999 65

Weather Vanes by MailMail-order weather vanes cost any-where from $40 to more than$1,000. You can browse the Web(just search for “weather vanes”) orrequest a catalog from one of thefollowing suppliers:

CCOOLLOONNIIAALL CCUUPPOOLLAASS:: Dept. TFH,1816 Nemoke Trail, Haslett, MI48840; (517) 349-6185.CCRROOSSSSWWIINNDDSS GGAALLLLEERRYY IINNCC..::Dept. TFH, 29 Buttonwood St., Bris-tol, RI 02809; (401) 253-0344.DDEENNNNIINNGGEERR WWEEAATTHHEERR VVAANNEESS&& FFIINNIIAALLSS:: Dept. TFH, 77 WhippleRd., Middletown, NY 10940; (914)343-2229.

vents, brick mold and postswith acrylic latex caulk. Waterthat gets into the vent housingmay lead to peeling paint.You can also use caulk and aputty knife to cover the screw-heads in the brick mold. n Acrylic latex paint is thebest finish for the wood parts.But always prime cedar withan oil-based primer designedto seal in “tannins,” naturalchemicals that bleed throughlatex paint, leaving brownishstains.

THE TRICKY PART:A WITCH’S CAP ROOFThe curved roof is the mosttime-consuming part of thisproject. Here are some tips tomake the job go smoothly:n Use a jigsaw to cut thecurved rafters. Don’t worryabout making the curves per-fect. The roof sheathing willsmooth over bumps and dips. n Mark the curves for the roofsheathing using a piece ofdoor stop and a bar clamp likeyou did for the rafters

66 JULY / AUGUST 1999 THE FAMILY HANDYMAN

(Photo 6). The curve is grad-ual enough to be cut with acircular saw set to a cuttingdepth of about 1/2 in.n The gaps between the piecesof sheathing at the ridges(Photo 8) will allow the ridge-cap shingles to curve gentlyover the ridges. If you placethe sheathing pieces tightlytogether, you’ll get a sharpridge and the shingles willcrack when you bend them. n Cut full-size shingles into 4-in. wide strips with a utilityknife, using a framing squareas a guide. Each of the threetabs on a full shingle is about12 in. wide., so you’ll get ninesmall shingles from each fullshingle.

CLIMB UP TO THE ROOFTOPIf your roof is too steep tocomfortably walk and standon, you’ll want to use roofbrackets (Photo 17) and/or asafety harness. (For a guide tosafety equipment, see “RoofSafety,” March ’96, p. 60. Toorder, see p. 112.) Andremember that rooftop safetyalso includes keeping awayfrom power lines.

If you don’t want ventila-tion, simply mount the sad-

FULLSHINGLES

5"

STARTERSTRIP

SHINGLES CUTTO 4" WIDE

ROOFINGCEMENT

5" LONGSHINGLE

RIDGECAP

3"

METALFLASHING

CUTHERE

SHINGLE the roof begin-ning with a “starter strip,”a full shingle nailed to theroof upside down. Thestarter strip should over-hang the plywood byabout 3/4 in. With thestarter strips in place,begin nailing on the 4-in.wide shingles. As with theplywood roof sheathing,leave a gap between theshingles at the ridges.Glue the lower edge ofeach 4-in. tab down with adab of roofing cement.

NAIL the ridge cap shin-gles over the ridges. Layheavy beads of roofingcement along both sidesof the ridge. To make theshingles conform to thecurve of the ridge, we cutthem 5 in. long. The firstshingle on each ridgemust be cut to match thecorner of the roof. The cor-ners of the stiff shinglesmay stand up at first, buta few hours in the hot sunwill make them lie flat.

CAP the roof by folding a 9 x 14-in. piece of flashingaround the peak (see Fig.A). Hold the flashing inplace while you mark itfor cutting. When the capis cut, fold it back into itspyramid shape, squeeze alarge blob of roofingcement into it, press itonto the peak and driveone roofing nail throughthe side of the cap thathas the overlappingseam.

H O W T O B U I L D A C U P O L A

9

10

11

ROOF PITCHGAUGE

CENTER OFSADDLE

3/4" PRESSURE-TREATEDPLYWOOD

4" TO 5"

FLASHING

SEAM

SCREWSFLAP

MARK two sides of thesaddle using your roof-pitch gauge. Place thepoint of the gauge onthe center line about 4 in. from the top of thesaddle and align thelegs of the gauge withthe inside edges of thesaddle. Then cut outthe V-shaped notchthat will straddle theridge of the roof. Forthe saddle’s construc-tion, see Fig. A.

WRAP flashing tightlyaround the saddle andfasten down the seamwith self-tappingscrews. To crease flash-ing around corners, usea hammer and woodblock. When the saddleis wrapped, fold downthe overhanging flash-ing along the top andbottom edges. At the V-notch, cut the flash-ing, fold the flaps intothe saddle and secureeach flap temporarilywith one screw. All ofthis is a lot easier if youhave a helper. And besure to wear gloves—orplan to visit the emer-gency room for stitches!

Custom-fit the Saddle

CONSTRUCT a roofpitch gauge by layingtwo boards over theridge of your roof andscrewing themtogether.

12

13

14

dle, as shown in Photo 15,without doing anything toyour roof. If your cupola willbe used for ventilation, you’llhave to cut a hole in your roof.The hole should be about 16 in. wide at the ridge andextend 10 to 14 in. down fromthe ridge, depending on thepitch of your roof.

You can cut the hole with acircular saw or jigsaw, but becareful to cut only throughyour roof’s sheathing and notinto any of the structural lum-ber underneath. Cuttingthrough asphalt shingles willruin a saw blade. So either usean old blade or first cut awaythe shingles with a utilityknife.

The cupola isn’t terriblyheavy: The three parts weighabout 80 lbs. altogether. Butthey are large and clumsy. Ifyou’re not comfortable carry-ing them up a ladder, rentscaffolding (about $10 perday for a 5-ft. tall section). Fora typical garage, you’ll needonly one section of scaffold-ing. For a one-story house,you may need two sections.

Once the cupola is on theroof, all that’s left is screwingthe three parts together,caulking and touching up thepaint. Now there’s somethingto crow about!

THE FAMILY HANDYMAN JULY / AUGUST 1999 67

SILL

VENTHOUSING

SADDLE

Screw the three parts together and you’re done!

2x2RAIL

ROOFBRACKET

ROOFINGCEMENT

CAULK

CLEATFLAP

4" MINIMUM

FASTEN the vent hous-ing to the saddle by dri-

ving 3-in. screws throughthe sill into the 2x2 rails

inside the saddle. Be surethe housing is centered

on the saddle before youdrive any screws.

DRIVE 2-in. screwsthrough the soffit intothe roof’s plywoodbase. Then caulk overthe screwheads andtouch them up withpaint.

FASTEN the saddle to theroof with 2x2 cleats. First

lay a bead of roofingcement on the roof along

each sloped side of thesaddle. Then fold the four

flaps down over thecement (cut them back if

they extend over the roofhole). Drive 2-in. screws

through the 2x2s into thesaddle and 3-in. screws

into the roof. Seal the gapat the ridge with roofing

cement and caulk aroundthe upper edge of the sad-dle. But leave the two low

edges of the saddleunsealed so any water

that gets in can drain out.

15

16

17

Art Direction • BILL FABER and HOPE FAYPhotography • ROBERT BRANTLEY and MIKE KRIVITTechnical Art • EUGENE THOMPSONGuest Rooster • “RED”

THE FAMILY HANDYMAN JULY / AUGUST 1999 69