(ASHLAR Fireplace & Chimney Services)
The crown of a masonry chimney is a concrete top that ideally looks something like the one shown. It has an angled top to shed water and it overhangs the brick to keep drips off the chimney sides. It surrounds the clay flues but doesn’t encase them. A 1/4-in. gap allows the clay flues to expand and contract from repeated heating and cooling without cracking (or cracking the crown). (The flues “float” inside the brick chimney walls; that is, they’re supported by the brick but not attached to it.) A high-quality polyurethane caulk seals the flue/crown gap and prevents water penetration.
In truth, few chimneys built before the mid-1980s have crowns built this well. Many early crowns were simply sloped washes of leftover mortar. Most have cracked and deteriorated, opening gaps around the flues.
Over time, normal expansion and contraction cycles can cause cracks to form, as shown. Sealing the chimney crown with crown sealer, a flexible elastomeric coating, is the best way to stop existing cracks from spreading and prevent new ones.
ASHLAR Fireplace & Chimney Services Provides you with a few options when it comes to Chimney Crown repair.
- A complete rebuild
- Repair spider cracks
- Waterproofing the crown with sealer
- installing a metal chase to cover the crown
We need to physically inspect the crown in order to make appropriate recommendation. Please dont hesitate to call us
at 604-655-7663 for consultation.
If you like to do this yourself. You can follow instruction over at Family Handyman