I Repairing & Replacing Chimney Caps

CHimney caps undergo stress because the temperatures of the cap and chimney flue fluctuate dramatically. Use fire-rated silicone caulk to patch minor cracks. For more extensive repairs, reapply fresh mortar over the cap, or replace the old cap for a permanent solution.

Tools & Materials ►

Floating chimney cap (shown cutaway, with form in place for illustration purposes)

Elle m D I om. way

Hammer Stone chisel Wire brush Drill

Float

Pointing trowel Tape measure Caulk gun Latex-fortified mortar Concrete fortifier

Plywood {Vi. V") Vs" dowel 1V" wood screws Vegetable oil or a commercial release agent Fire-rated silicone caulk Fire-rated rope or mineral wool Work gloves

A chimney cap expands and shrinks as temperatures change inside and outside the chimney. This often results in cracking and annual treks up to the roof for repairs. A floating chimney cap (above) is cast in a form using mortar or sand-mix concrete, and then placed on the top of the chimney (opposite page). You can repair a damaged cap by chipping off the deteriorated sections and adding fresh mortar (below).

подпись: 
 chimney caps undergo stress because the temperatures of the cap and chimney flue fluctuate dramatically. use fire-rated silicone caulk to patch minor cracks. for more extensive repairs, reapply fresh mortar over the cap, or replace the old cap for a permanent solution.
tools & materials ►
 
 floating chimney cap (shown cutaway, with form in place for illustration purposes)
 
 
 elle m d i om.way
 
 
 
 hammer stone chisel wire brush drill
float
pointing trowel tape measure caulk gun latex-fortified mortar concrete fortifier
 plywood {vi. v") vs" dowel 1v" wood screws vegetable oil or a commercial release agent fire-rated silicone caulk fire-rated rope or mineral wool work gloves
 
 a chimney cap expands and shrinks as temperatures change inside and outside the chimney. this often results in cracking and annual treks up to the roof for repairs. a floating chimney cap (above) is cast in a form using mortar or sand-mix concrete, and then placed on the top of the chimney (opposite page). you can repair a damaged cap by chipping off the deteriorated sections and adding fresh mortar (below).

 

 

How to Repair a Chimney Cap

 

Carefully break apart and remove the deteriorated sections of the chimney cap using a stone chisel and hammer.

Mix a batch of latex-fortified mortar. Trowel an even layer of mortar all the way around the chimney cap, following the slope of the existing cap. Mortar should cover the chimney from the outside edges of the chimney bricks to the flue. Smooth out the mortar with a wood float, trying to recreate the original slope of the chimney cap. Inspect the mortar annually.

Measure the chimney and the chimney flue and build a form from 1/2 and %" plywood (form dimensions on opposite page, top). Attach the form to a plywood base using VA" wood screws. Glue %" dowels to the base, 1" inside the form. The dowels will cast a drip edge into the cap. Coat the inside of the form with vegetable oil or a commercial release agent.

Prepare a stiff (dry) mixture of mortar to cast the cap—for

Average-sized chimneys, two 60-lb. bags of dry mix should yield enough mortar. Fill the form with mortar. Rest a wood float across the edges of the form and smooth the mortar.

Keep angles sharp at the corners. Let the cap cure for at least a week, and then carefully disassemble the form.

 

Chip off the old mortar cap completely, and clean the top of the chimney with a wire brush. With a helper, transport the chimney cap onto the roof and set it directly onto the chimney, centered so the overhang is equal on all sides. For the new cap to function properly, do not bond it to the chimney or the flue.

Shift the cap so the gap next to the flue is even on all sides, and then fill in the gap with fire-rated rope or mineral wool. Caulk over the fill material with a very heavy bead of fire-rated silicone caulk. Also caulk the joint at the underside of the cap. Inspect caulk every other year and refresh as needed.

Добавить комментарий

Ваш e-mail не будет опубликован. Обязательные поля помечены *