We recently remodeled the den, and built a new stone fire place on top of a concrete slab, adjoining our pier and beam house. The hearth, made of inch and a half thick granite, sits directly on top of the wooden subfloor.
Directly beneath where the fire place and hearth join together, the rim joist under the house caught on fire. The cause was apparently either live embers dropped down between the fire place and hearth (not likely since it was grouted and appeared tight) or excess heat radiating down and through the granite.
The entire project was permitted, built by professionals and passed inspection. Fortunatly, the damage was fairly minor.
Anyone have a similar experience and insight as to the cause of the fire?
Replies
I guess this is a common design fault, so much so I was told by the inspector that I had to have a certain guage of metal flashing between the fireplace and hearth joint .. sorry about your fire ..
Back when DW was a firegal, she ran into one of these in a relatively new house - she got to hack up the floor!
Hope not too much damage -
Forrest
It was not built to code and the definition of 'professionals' here is limited to those who profess to know what they are doing but really do not.
That hearth hould not have been on top of combustible materials.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
Standard code practice here is to lay a 4" wide slip of galvanized steel under the junction of the hearth stone and the fireplace to prevent live embers from penetrating this gap and lighting the subfloor on fire. I'm guessing that is what happened, not that heat radiated through the hearth stone and lit the subfloor on fire.
It's not something that the inspectors can readily verify once the stone is set and the practice is for the strip to not be fastened to the subfloor but just left in place by the fireplace sub and covered over by the stone sub. If it gets knocked out of position in the intervening time it can get picked up as a piece of scrap and discarded very easily.
You can put a single nail in it but two will cause it to buckle when it gets hot ad you want it loose anyway so you can sweep the sawdust out from under it before setting the stone.
------------------
"You cannot work hard enough to make up for a sloppy estimate."