Chimney repair in Littleton.

1. Crowns.

   A crown is the concrete lid poured over the top of the masonry. It sheds water off the brick and the flue, and it gets the hardest use: a night freeze, an afternoon thaw, another freeze.

   Ice takes up about 9% more room than water, so a hairline crack that fills and freezes is forced wider on every cycle. Seal a hairline crack while it is small; a crown that has crumbled or pulled away from the flue tile has to be rebuilt.

   

2. Caps and spark screens.

   Birds, squirrels, rain and snow are stopped at the top of the flue by the cap, and its screen is the spark arrestor. Section R1003.9.2 of IRC 2021 lets the openings run from 3/8 to 1/2 inch.

   Hail is the cap’s other enemy: on May 8, 2017, stones up to baseball size fell across the Denver metro area (NWS Boulder). Dents, loose fasteners and a flattened screen are what to look for afterwards.

   

3. Flashing at the roofline.

   Flashing seals the gap where the chimney comes through the roof. Snow piles up on the uphill side and melts slowly there, so a lifted edge or tired sealant lets water in at exactly that spot. The first sign tends to show up indoors, as a brown stain on a ceiling or an attic wall near the chimney.

   

4. Mortar joints and brick.

   Mortar is meant to give way before the brick does. Once joints open, water gets behind the brick face and each freeze pops flakes off it, a failure called spalling.

   Tuckpointing packs fresh mortar into worn joints before the bricks loosen. A brick that has cracked right through or flaked badly gets cut out and a new one set in.

5. Firebox.

   Fire hits the firebrick and its mortar head-on. Open joints and cracked brick let heat through to what is behind the firebox, so a small repair here protects the framing around the fireplace.

   

6. Flue liners.

   Up the middle of the chimney runs the liner, which carries smoke and heat out of the house. If a tile has cracked or slipped, heat can reach the framing and gases can reach the rooms, yet from the firebox or the roof the fault usually cannot be seen. A camera pass up the flue, part of a Level 2 inspection, finds it. The median home in Littleton was built in 1982, so many liners are well into their fourth decade.

   

7. Framed chases and their covers.

   A framed chimney is a box built and finished like the house around it, topped with a metal cover. When the cover rusts through or sags, rainwater collects on it and drains down the inside of the chase. Add a cap and screen to the flue, and a cover that sheds water, and nothing wet reaches the interior.

Ask about a repair