fireplace hearth extension rules fireplace construction stove hearth size and thickness fireplace chimney clearances chimney kandla grey sandstone fireplace hearth 2018 international residential code white fan forced electric fireplace diamond chequer fireplace quarry hearth fireplace hearth majestic onyx direct vent gas fireplace concrete fire hearth 1 8m open fire flush wood hybrid fyre inserts wfp 75 hearthstone stoves cherry fan forced electric fireplace the log burner hearth regulations to georgian style marble fireplace mantel hearth boundaries gui from the made to measure slate fire hearths cut heritage hearthstone stoves chimney and fireplace clearance codes pleasant hearth 30 parkdale white fireplace design fireplace surrounds mantle and hearth considerations for fireplace hearth extension rules made to measure slate fire hearths cut mantle and hearth considerations for fireplace hearths an in depth guide kratki pl marek bal wood heater hearth clearance dimensions chimney and fireplace clearance codes fireplaces inserts gas logs s electric fireplace led reflection mantels the fireplace pe hearth concrete fireplace hearths anthony