43212 212th Ave SE
Enumclaw, WA 98022
360 802 1300, fax 360 802 6605
Madison Master Builders
Evaluation and Recommendations
by Jim Buckley, 11/22/06
Mason, Loren Bain, called me to report that the center throat tile had broken in a 36" Rumford fireplace he had built for Madison Master Builders. Loren also said the cast-in-place concrete surround had cracked. On Tuesday, 11/20/06, Loren and I met with builder, Tim Coulter, at the jobsite east of Redmond, WA.
As shown in the pictures above, the firebox shows evidence of an unusually hot fire, the throat had indeed failed and fallen out and the surround was stained with smoke and cracked. The home owner reported the crack in the top cast-in-place concrete mantle shelf opens up to about 1/2" when hot.
It's clear to me that the fireplace has been abused by burning very hot construction scrap wood fires in it. This is easy to tell from the burn pattern on the firebox. Normal fires will create a burn pattern like the one at the right where a fire playing up to about two thirds of the height of the firebox will burn the smoke off the fireback behind the fire about half way up the fireback. By comparison the damaged fireplace, with the smoke burned off the fireback well up into the throat, must have had a raging fire in it.
In addition there are smoke stains on the front of the fireplace surround indicating that the fire was probably built out on the hearth. The fuel load may have been similar to the pile of scrap in front of the outdoor fireplaces the day we were there.
There is also the possibility that the hot fires were built in the fireplace before it was cured or dried out. The masonry was wet when built and Loren reported that he had told the owner to wait for 28 days for the masonry to dry out and then build small break-in fires at first.
Abused or not, we are concerned that the throat tile failed. We were also surprised that the cast-in-place concrete surround was cracked. We wondered if the angle iron lintel supporting the throat tiles somehow got so hot and perhaps was restricted at the ends so could have expanded and forced the surround to crack. That may even have been a contributing factor in the throat failure.
Out of the thousands of segmented throats installed each year, we only know of three throat tiles that have broken. All appear to have been the result of burning very hot fires without first breaking in the fireplace. Interestingly, all three broken tiles have been the center tile in a 36" Rumford.
I recommend replacing the segmented throat with a 36" one-piece throat that we will provide. Loren will have to replace the surround so, when he removes the damaged one, maybe we can tell if the damage was caused by the steel angle lintel. In any case the one-piece throat is not supported by an angle so the replacement will eliminate this as a possible cause of the problem.
Loren also said he wished we still offered the "Certified Core Kits" so we will provide him with a certified door, to install when he rebuilds the surround.
While we think the fireplace was abused by burning construction scrap, we still think our components should take a certian amount of abuse. We also want to support Loren, our mason customer, who built the fireplace correctly according to our Instructions and, together, we want the builder to know that we stand behind our product. For these reasons we are happy to provide a replacement throat and fireplace door to Loren and are greatful that Loren is willing to rebuild the throat and surround.
Buckley Rumford Fireplaces
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