National Chimney Custom Chimney Cap

This is a custom chimney cap, cut and built to your measurements by National Chimney, for masonry chimneys with one flue or several. It covers the whole top of the chimney: the flue tiles, the crown, and the joints between them where water gets in. Rain, snow, leaves and animals stay out, sparks stay in, and the lid lifts off when the sweep comes. Enter your chimney's measurements in the configurator above, choose how it mounts, the lid, the height and the finish, and the price updates as you go. The Export PDF button saves a drawing of your cap to check against the chimney or hand to your roofer.

• Fits: masonry chimneys with any number of flues, and flat metal chase covers. Virtually any length and width.
• Material: 24-gauge 304 stainless steel, or copper. Powder coat in any RAL color over stainless.
• Mounts: standard skirt, pitched skirt, or top mount with a hinged flange.
• Lid: flat, hip, hip and ridge, or standing seam. Removable for cleaning. Overhang to your choice, 3 inches standard.
• Screen: 8, 10, 12 or 16 inches high, or any height you enter. 3/4 inch expanded stainless mesh.
• In the box: the cap, the lid fasteners, sealant and masonry screws.
• Made by: National Chimney, Indianapolis, Indiana. Built to order.

How to measure

You need three numbers, all taken on the roof with a tape measure, to the nearest quarter inch. Which two you take first depends on how the cap will mount.

Mount	Length and width	Screen height
Standard skirt or pitched skirt	The outside of the chimney at the top, edge to edge, the long way and the short way. The skirt wraps over the outside, so add a quarter inch to each so it slides on.	At least 4 inches taller than the tallest flue tile above the crown
Top mount	The footprint you want covered: the outside of the crown, or the area around the flue tiles with at least 2 inches of flat crown all round for the flange.	The same

Three things to check while you are up there. Squareness: measure each side at both ends and the two diagonals, and use the largest numbers. The crown: it should be sound, and for a top-mount cap it needs a flat band at least 2 inches wide for the flange; a crumbling or badly cracked crown should be repaired first. The roof: the lid overhangs the screen on every side, 3 inches unless you change it, so make sure nothing is in the way.

Not sure? Send us the numbers and a photo of the chimney top before you order, and we will check them. Every custom cap is checked by a person before it goes to the shop.

Choose your cap

Mount style

Standard skirt. The cap sits over the top of the chimney like a lid on a box. A horizontal skirt, 2 inches wide as standard, rests on the top of the brick, and a vertical skirt, 3 inches as standard, hangs down the outside and takes the masonry screws. The crown edge, where water usually gets in, is covered completely. A drip edge on the bottom of the skirt throws water off the brick.

Pitched skirt.