Chimney chase repair and framing work in Kirkman South

How a failed top sends water down the chase

When the metal top of a chase leaks, the water does not stay at the top. It runs down the inside face of the sheathing, along the studs and onto whatever sits at the bottom of the box, like the roof deck or a framed floor. Some of it can follow the outside of the chimney pipe toward the fireplace.

That is why a leak at the top can show up as rot at the bottom. The wood near the cover may look fine while the base plate has gone soft.

Replacing the cover is a separate job with a separate line. Our part is the wood and finish the water already reached. We trace the path from top to bottom so the repair covers everything that got wet, and not only the spot closest to the leak.

The screed along the bottom edge of the stucco

Stucco on a framed wall needs a clean stop at the bottom. A screed is a metal or plastic strip fastened along the base of the wall, and the stucco is finished against it. R703.7.2 says that on wood-frame construction with an on-grade floor slab, exterior plaster covers the lath, paper and screed but does not extend below them.

When stucco runs past the screed onto the roof, a slab or the flashing, water draining down the barrier has no way out. The bottom edge stays wet, and over time the plate behind it can rot.

On a stucco chase in Kirkman South, our crew checks where the stucco stops at the base and along any roof line. If it runs past the screed or is buried in roofing, we cut it back to a clean edge so water can leave the wall. That edge detail is written into the scope, since it is easy to lose once the finish coat goes on.

What a full chase rebuild involves

A chimney chase rebuild follows a set order. The fireplace is taken out of use, the cover and chimney cap come off, and the siding and sheathing are stripped down to the framing. Rotted framing is replaced and the box is squared and braced around the chimney pipe.

Firestops, shields and supports inside the chase are checked and reset to the chimney maker's instructions along the way. For homes in Kirkman South, the full sequence is laid out in the written estimate before work starts. The new chase goes together in this order.

• New framing laid out to keep the listed air space around the pipe
• New sheathing, barrier and flashing at the roof and house wall
• The chosen siding or stucco, trim and paint
• A new or reset cover at the top, priced as its own line

Cables and wiring routed through a chase

A chimney chase can look like a handy path to the roof. Cable, satellite and low-voltage lines sometimes get run up through it, and an outlet or light may be mounted on its outside wall with wiring behind. Those lines are often added long after the chimney went in.

DuraVent's manual, for example, tells installers to keep electrical wiring away from all chimneys and lists wiring among the combustible materials that stay outside the required clearance. Wires resting on the pipe or stapled across the air space have to be moved.

With the chase open, we flag any wiring in the clearance space. Low-voltage cables are rerouted clear of the pipe. Anything on a household circuit is left for an electrician and noted as a separate item on your Kirkman South estimate. Satellite mounts screwed into the chase get checked for leaks at the screw holes.