10.3. Built-in Gutter Linings

Description: Copper gutter linings are most often built into wood framed supporting structures. Although the copper lining conforms closely to the gutter frame profile, it should not fit tightly. The lining must be free to move. The bottom of the frame may be pitched to provide positive drainage to the downspout. The inner edge of the lining should finish not less than 2" above the outside edge.

Copper linings should be constructed of sheets 10' maximum in length without longitudinal seams. The ends of the sheets must be pre-tinned 1-1/2". Adjacent sheets are joined by 1-1/2" lapped, riveted and soldered seams. If the girth of the gutter is more than a sheet of copper (typically 36" in some cases 48"), the cross seams should not be more than the sheet width apart (36" or 48").

Expansion joints are placed at intervals to accommodate thermal movement of the gutter lining. See Table 10B for spacing of expansion joints and downspouts. Expansion joints should also be provided within a short distance of the downspout if the gutter lining forms the leg of an inside or outside corner. If an expansion joint must be accommodated at the corner itself, it should be constructed as shown in Detail 10.3B.

Clearance for downspouts through the wood framing, is a minimum 1/2" all around.

Special Conditions: The details shown are for the lining of a wood box gutter frame. When lining a masonry cornice, the edge strip can be secured to the masonry cornice with brass screws and lead shields 12" apart. If a reglet is used, the edge strip is secured into the reglet with lead wedges and sealant.

Note: For ease of soldering, whenever possible, built-in gutters should be fabricated outside of the gutter framing to allow soldered seams inspection and watertightness testing of the gutter, prior to final gutter system installation.

10.3A. Built-In Gutter at Inside Corner

This detail shows a one piece copper gutter lining and apron design that is suitable for use in areas with ice or snow conditions. The apron extends a minimum of 6" onto the roof.

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Where the lining meets the vertical wall, provide at least 1/2" for expansion. Section 1 of Detail 10.3A shows this dimension, along with two methods of flashing. Method A shows a typical end condition with an expansion joint cap, recommended in areas with ice and snow conditions. Method B is used in areas with no ice and snow conditions.

Section 2 of Detail 10.3A illustrates a flashing method for the portion of the apron that rests on the roof.

A continuous edge strip of 20 oz. cold rolled copper is formed and attached along the outer edge of the gutter frame with copper nails or brass screws. The copper gutter lining hooks over the edge strip forming a 3/4" loose lock.

10.3B. Built-In Gutter at Outside Corner

This detail shows an outside corner condition where expansion must be accommodated at the corner. Only the copper gutter, apron and flashing are shown. The roofing extends beyond the edge of the apron as shown in Detail 10.3A. The corner must allow movement in both copper linings. It is framed in wood then covered with a corner expansion joint cap. A copper angle deflector is soldered onto this cap to direct water into the gutter.

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DWG iconDownload CAD File technical detail
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This detail shows a one piece copper lining and apron. The apron is secured to the sheathing with copper cleats. It is suitable for areas where ice and snow conditions exist.

See discussion on expansion in Hung Gutters page and Table 10B for more information on required dimensions.

Section 2 of Detail 10.3B illustrates the various components at the outside corner. The expansion joint cap is placed on wood sheathing and folded over the top gutter-end flange. Its upper edge is locked and soldered into the hip flashing.

10.3C. Built-in Gutter

In this built-in gutter detail, continuous copper cleats are used to secure the gutter lining in place. At the coping, a continuous cleat is anchored to wood blocking with nails at 3" O.C. Just below the eave of the roof, another continuous cleat is attached to the fascia. A copper panel with stiffening ridge is used as counterflashing to complete the closure between the copper roofing system, and the gutter lining. The panel is secured with the cleat at its upper end, and with a lock-strip soldered to the gutter lining at its lower end. The top of the rear edge of the gutter lining must be higher than the front edge to prevent potential leaks into the building.

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10.3D. Built-in Gutter

This detail is similar to Detail 10.3C except that a continuous reglet in the stone coping is used to anchor a continuous cleat. This eliminates the need for wood blocking, and in some cases may simplify the installation of the gutter lining. The cleat is inserted into the reglet, grouted in, held by lead wedges and sealed, or fastened with bronze screws and expansion shields and sealed.

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10.3E. Built-in Gutter

In this detail, a one-piece copper gutter lining and apron is used in conjunction with a standing seam roof. The upper edge of the gutter apron extends at least 6" onto the roof and is folded over and held by cleats at 12" O.C. A continuous lock strip is soldered to the apron at least 4" below its upper edge. The lower edge of the copper roof is hooked over the locking strip.

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This detail is recommended for roofs with a pitch of at least 6 inches per foot. For roofs with lower pitches, see Detail 10.3D.

10.3F. Transverse Seams in Gutter Lining

Where seams occur in the copper gutter lining, a locked and soldered or riveted and soldered are required to maintain a watertight gutter condition. The seam should be oriented to allow the water to flow away from the joint. Rivets are installed in a staggered pattern at 3" O.C.

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