Chimney & fireplace
Chimney Crown Cost Calculator
Prices a crown, which is a concrete slab rather than mortar and fails when it is treated as mortar.
Result
A planning estimate, not a quote. Access, the age of the equipment, what is found once it is opened up and local labour rates all move the real figure, sometimes a long way.
Get a Free Business AuditHow the calculation works
Hours times crew times rate, plus materials and the call-out. The crown is the slab across the top of the chimney that sheds water off the masonry, and a correct one is cast concrete with reinforcement, sloped away from the flue, overhanging the brickwork with a drip edge, and separated from the flue tile by an expansion joint so the two can move independently. Forming that properly is a half-day job with materials; parging mortar across the top is quicker and is why so many crowns fail.
What moves the number
- Whether a proper cast crown is formed or mortar is parged over.
- Chimney dimensions, which set the material quantity.
- Access and staging, which dominates a small material cost.
- Whether the top courses of masonry need repair first.
Where this one goes wrong
A mortar wash is not a crown. Mortar is not designed as a horizontal weathering surface, it has no reinforcement, it does not overhang, and it bonds hard to the flue tile so thermal movement cracks it, which is exactly the pattern seen on most failed crowns. Water then enters the top of the chimney and causes the spalling and deterioration below. A cast crown with reinforcement, a slope, an overhang and an expansion joint at the flue costs more and lasts an order of magnitude longer. An existing cracked crown can sometimes be overlaid with a flexible crown coating rather than replaced, which is a legitimate middle option.
Before you quote
- Cast a reinforced crown with a slope and an overhang, not a mortar wash.
- Form an expansion joint between crown and flue tile.
- Repair the top masonry courses before casting.
Questions
About this calculator
What is the difference between a crown and a cap?
The crown is the concrete slab across the top of the chimney that sheds water off the masonry. The cap is the metal cover over the flue opening that keeps rain and animals out of the flue itself. They do different jobs and a chimney needs both.
Why do chimney crowns crack?
Most often because mortar was parged over the top instead of a reinforced concrete crown being cast. Mortar is not a weathering surface, has no reinforcement, does not overhang, and bonds hard to the flue tile so thermal movement cracks it. That cracking is what lets water into the chimney.
Can a cracked crown be repaired rather than replaced?
Sometimes, with a flexible crown coating applied over it, which bridges hairline cracking and restores the water shedding. Where the crown is badly broken, has no overhang or is failing structurally, recasting is the proper answer. It is a judgement from the condition rather than a preference.
The formula
total = hours x people x rate + parts + call-out, then sales tax
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How to use this calculator
- Hours on site (h). Enter your own figure; the page starts at 2 h.
- People needed. Enter your own figure; the page starts at 1.
- Labour rate charged ($). Enter your own figure; the page starts at $125.
- Parts and materials ($). Enter your own figure; the page starts at $65.
- Call-out or diagnostic fee ($). Enter your own figure; the page starts at $95.
- Sales tax (%). Leave at zero if you are quoting before tax.
The result updates as you type, so you can try a figure, see what it does to estimated total, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Hours on site | 2 h |
| People needed | 1 |
| Labour rate charged | $125 |
| Parts and materials | $65 |
| Call-out or diagnostic fee | $95 |
| Sales tax | 0% |
What comes out
| Result | Value |
|---|---|
| Estimated total main result | $410 |
| Labour | $250 |
| Before tax | $410 |
| Sales tax | $0 |
About $410: $250 of labour, $65 of parts and a $95 call-out.
How sensitive the answer is
Holding everything else steady and changing only labour rate charged, this is what happens to estimated total. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Labour rate charged ($) | Estimated total |
|---|---|
| $63 | $286 |
| $94 | $348 |
| $125 example above | $410 |
| $188 | $536 |
| $250 | $660 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Hours on site (h)
- Measured in h, between 0 and 400, starting at 2 h.
- People needed
- A number, between 0 and 40, starting at 1.
- Labour rate charged ($)
- A money amount, starting at $125.
- Parts and materials ($)
- A money amount, starting at $65.
- Call-out or diagnostic fee ($)
- A money amount, starting at $95.
- Sales tax (%)
- Leave at zero if you are quoting before tax.
What the results tell you
| Result | What it is |
|---|---|
| Estimated total | The headline result. A money figure. |
| Labour | A money figure. |
| Before tax | A money figure. |
| Sales tax | A money figure. |
Estimating is the easy part
The jobs you never hear about cost more than the ones you mis-measure. BDEVY builds the marketing, systems and automation that bring them in.