Clean Sweeps of Michigan's Blog

Firebox Replacement and Repair

The firebox is the part of the fireplace system that contains intended fires. It is the “fire pit” in the system, the place where you build and start your fires. It is also designed to contain heat from those fires and prevent it from reaching the structure of your home.

As a result, damage to it – as well as basic incompatibility with the rest of the fireplace system – needs correction through either repair or replacement. Cracks in fire bricks or refractory panels are cracks in your home’s defense against fire. If the firebox is an insert that really does not fit the rest of your system, you are probably losing both draft and cash.

What to Do?

Without inspecting your system, we really cannot say whether repair is an option for the cracks you see. In general terms of fireplace health, it is important to diagnose the underlying cause before attempting to treat the symptom. That said, minor firebox cracks can usually be filled with special fire clay or refractory mortar.

Crumbling firebrick or extensive cracking require more significant ‘repair’ for problems that may have more worrisome causes. Either means removal and replacement of the damaged components, whether bricks or panels. Panels are generally easier to re-place than bricks but the only bricks that have to come out are the damaged ones.

If the problem that needs correction is a bad fit of firebox to system, again, it really needs to be seen to address it. However, it is common for an existing flue to be too large for an inserted firebox. In that case, it is impossible for the chimney over the firebox to ‘withdraw’ air from the fireplace effectively. That has consequences for both safety and utility bills but repair or replacement cannot be determined until a full inspection has taken place.

Changing Your Oil-Stove to a Wood Stove

The conversion of a stove to allow for the use of a different fuel is possible but complicated and requires involvement by professionals. Some of what they do is necessary anyway, so if a change is on your mind, consultation can be part of this spring’s chimney inspection. Your sweep can tell you the feasibility of your plan and what you need to do, given your own unique circumstances.

Venting Is Still the Issue

First, a CSIA certified chimney sweep needs to inspect your venting system to determine whether it can handle the conversion or will need to be changed itself. Stacks designed to vent smoke from oil are not necessarily equipped to handle the different combustibles produced by wood. Second, if the flue can stay, it has to be thoroughly cleaned, and the chimney has to be in good condition regardless.

A different firebox will almost certainly be required, and your chimney sweep should be involved with that, too. It needs to be sized properly for the flue to vent the different gases produced by burning wood. Insufficiencies that may not be apparent in a stove’s oil-burning performance can show up when the smoke going up it is different.

Ask a Chimney Sweep

Certified chimney sweeps are also familiar with the ease or difficulty of new installations and can guide your understanding of their likely expense. They are up to date on clearances and codes and can be a valuable source of information needed for this conversion. They need to come out and check your system anyway, so take full advantage of everything they can offer.

Another important thing to consider in this process is where the wood is going to be stored. The right balance of convenience and safety has to be struck, with wood kept far enough away from the house to be safe. Even this kind of thing is worth discussing with a chimney sweep, because they will have plenty of ideas on how to make your home and stove safer.