What Firebox Repair in Flower Mound Covers
The firebox takes more heat than any other part of the fireplace, and it is the part that most Flower Mound homeowners never look at closely. Flower Mound Chimney Sweep Professionals repairs both kinds of firebox found in the area.
Factory-built fireplaces make up most of the homes built from the 1990s on in Bridlewood, Wellington, Lakeside DFW and the newer parts of Flower Mound and Lantana. Their firebox is a thin steel box lined with refractory panels. When a panel cracks or crumbles, the steel behind it gets the full heat of the fire, and behind the steel is the wood-framed chase.
Masonry fireplaces are common in the older homes near Grapevine Lake, Lake Lewisville and the Cross Timbers woods. Their firebox is firebrick laid in thin refractory mortar joints. The joints fail first, then the bricks loosen and spall.
| Firebox type | What fails | Repair |
|---|---|---|
| Factory-built, refractory panels | Cracks wider than a coin, crumbling edges, panels that move | Replace the panel with one cut to fit the unit |
| Factory-built, floor panel | Broken floor sections under the grate | Replace the floor panel, check the metal below for rust |
| Masonry firebrick | Mortar joints washed out or missing | Grind and repoint with refractory mortar |
| Masonry firebrick | Cracked, spalled or missing bricks | Cut out and relay matching firebrick |
| Masonry floor and hearth | Sunken or cracked floor, gaps at the hearth | Rebuild the floor course, repoint the hearth joints |
Every firebox repair starts with photos and a camera check of the flue above it. You get a written price before we start.
Signs You Need Firebox Repair
- A crack in a refractory panel wide enough to hold a coin edge
- A panel that rocks or clicks when you press it
- Pieces of panel or brick on the firebox floor after a fire
- Mortar joints you can scrape out with a fingernail
- Bricks with a flaked, pitted face
- Rust streaks on the metal visible through a gap in a panel
- Heat on the wall beside or above the fireplace while it burns
- A fire that burned unusually hot, or a chimney fire, in the past year
The Chimney Safety Institute of America covers what a yearly inspection should catch, including firebox damage, in its homeowner resources. Heat on the wall while the fire burns means stop using the fireplace until we look at it.
How We Replace Refractory Panels
- Identify the unit. The metal tag inside the firebox gives the make and model, which tells us the panel sizes.
- Remove the old panels. The screws, clips or lugs holding the panels come out, and the cracked panel lifts free. We vacuum the firebox and look at the steel behind it for rust or warping.
- Fit the new panel. Panels are cut to the exact size of the unit. Where a factory panel is no longer made, a universal refractory panel is cut to fit.
- Set and secure. The panel goes in with the manufacturer’s clips and a bead of refractory cement at the joints.
- Cure. Refractory cement needs a day to cure, then two or three small fires before a full load.
Replacing one panel takes about an hour. All four, with a floor, about half a day.
How We Repoint and Rebuild Firebrick
Mortar in a firebox is not regular mortar. It is a thin refractory mix rated for heat, laid in joints about a quarter inch wide. We grind the failed joints out to a sound depth, brush and vacuum the dust, dampen the brick and pack new refractory mortar into the joints. Bricks that are cracked or spalled are cut out and replaced with firebrick of the same size. A sunken floor is taken up and relaid on a fresh bed. Repointing cures for a day before the first small fire.
Masonry chimneys with a failing firebox often have the same problem outside. Our chimney tuckpointing page covers the mortar joints on the stack, and a chimney that has lost brick as well as mortar may need the work on our chimney rebuild page.
Why Fireboxes Fail in Flower Mound
- Hot, short fires. Lighting a full grate with a gas starter and burning for an hour heats the panels fast and cools them fast. That cycle cracks refractory cement.
- Water from above. Spring hail cracks crowns and loosens caps. Rain runs down the flue, soaks the smoke shelf and the back wall of the firebox, and washes out mortar.
- Wet firewood. Green post oak and cedar elm burn cool and smoky, so people pile on more wood to get heat, and the extra load overheats the back wall.
- Age. Panels from a 2002 builder-grade fireplace are past their rated life.
A clean firebox shows damage sooner. A yearly fireplace cleaning is when most of our firebox repairs are found, and a fireplace inspection before the first fire in a house you just bought catches panels the seller never noticed. If the camera finds the smoke chamber above the firebox rough and cracked as well, smoke chamber cleaning and parging are done in the same visit.
Book Firebox Repair in Flower Mound
Flower Mound Chimney Sweep Professionals is veteran-owned and based on Long Prairie Rd (FM 2499) in Flower Mound 75028. We repair fireboxes in Flower Mound, Lewisville, Southlake, Colleyville, Keller, Fort Worth and Collin County, 7 days a week from 7 AM to 8 PM. Call (817) 518-6131 or send the form on this page. You get photos of the damage, a free written estimate, and a firm price before any panel or brick goes in. For dampers, gas parts and smoking fireplaces, start at our fireplace repair page.
