This can also apply to bay windows and cantilevered sections of homes. 

In the picture below notice the prefab fireplace enclosure on the rear center of the house. Left of the wood stairs.  In this instance the board under the enclosure is not completely sealed.

In the below picture the yellow flexible CSST gas line is coming through a pipe and is not sealed.  Many times the pipe is not there and the gas line is extended through a larger hole.  The air infiltration at this point is felt very easy and due to the low temperature outside this tile hearth is very cold to touch and the floor is cold. 

This is very common in the inspections that I've done on "cold rooms" and there has been a prefab fireplace in this type of configuration installed.

Plumbers are now using millpak to seal this opening but this is still not enough in my opinion.  

I feel the exterior enclosure should be insulated better and the bottom board better sealed. 

During a lot of inspections in the winter with these types of prefab fireplaces, I see that there are blankets, plastic, pillows, insulation or whatever they have any blocking the cold air from these fireplaces.

If you have a cold spot here... this is where I would start to look.

Check with a qualified contractor to correct any insulation or sealant issues with this enclosure to insure that flammible materials do not come into contact with hot areas and to make sure the enclosure gets properly sealed.

Rick A. Harrington

Patch Independent Home Inspections, LLC

www.patchhomeinspections.com

www.thermalimagescanning.com