Sound chimney flues restored in Thornton Park

Tiles broken across their width

A tile broken horizontally can let the upper piece settle or tilt, leaving a ledge inside the flue or a gap in the wall. Broken edges also shed fragments that fall down to the smoke shelf or into the firebox.

This kind of damage often limits what a surface repair can achieve, because the passage is no longer continuous. We check whether the pieces are still supported, whether the break is near the top where a section can be replaced, and whether the damage points toward relining instead.

The yearly check NFPA 211 calls for

NFPA 211, the national standard for chimneys, fireplaces, vents and solid fuel-burning appliances, calls for a yearly inspection of each chimney, fireplace and vent to confirm it is sound, not clogged with deposits and at correct clearances, with cleaning, upkeep or repair if the inspection shows a need.

A yearly look is how flue damage tends to get caught early, while a repair is still small. If your chimney has gone longer than that, our free inspection is a good place to start, and it tells you whether the flue needs anything at all.

Dark stains on the outside of the chimney

Dark, tar-like staining on the outside of a chimney can point to flue gases or condensate getting through damaged lining and soaking into the masonry. It can also come from water running off the top.

When we see this kind of staining, we look for the flue damage that could explain it and for water entry at the crown or cap. The findings tell you which is responsible. The pattern helps. Staining that follows a flue's position up the chimney and appears after fires points to the lining. Staining that spreads from the top down after rain points to water.

What decides the size of a flue repair

No two flue repairs are the same size. The scope depends on the findings, and each factor is spelled out in the estimate.

We explain each factor that applies to your chimney and how it shapes the recommendation.

• How many sections are damaged and where
• How tall the chimney is and how it is reached
• Whether the flue has offsets
• The product or material the repair needs
• Cleaning and preparation before the repair
• Related work at the crown, cap or smoke chamber