I have to say that I have had my Rumford design for three years now and I couldn't be more happy with the efficiency of the unit. I personally constructed my log home and I took considerable time researching the best fit unit for my home. It's looks and efficiency are excellent.

I am encountering a problem with the fireplace regarding the Portland joints used around the firebrick. It is starting to crack and fall out of the joints especially in the high heat areas. Can you suggest a good fix for this problem? I am thinking about the Heat Stop product (which I should have used in the first place) but my concerns are 1) how to clean the joint for proper adhesion and 2) will I have to grind out some of the Portland to make the joint deep enough.

Any recommendations you can provide would be greatly appreciated.

Respectfully,
Stephen N. Keller

That's a nice endorsement, Stephen, May I use it on our endorsements page at http://www.rumford.com/endorse.html? And can you send a picture of your Rumford?

As for the mortar, that's easy. Get a bag of HeatStop II (the dry hydraulic setting refractory mortar at http://www.rumford.com/store/cms.html) As the Portland mortar falls out, simply replace it with the HeatStop II.

You could dig or grind out more Portland cement but I would just scrape off whatever is loose and wash the joint with a sponge and water before packing the voids with the HeatStop mortar.

Mix a little of the HeatStop II with water to a consistency that will stay on a trowel but not be so stiff that it doesn't bond well. A mason would use a trowel to hold a little mortar against the firebox near the joint and use a narrow "pointing" trowel to pack the mortar into the joint. After a few minutes you should wash the surface of the fresh joint and firebox to get excess mortar off the brick and to make the joint look good - sort of like washing grout in a tile surface.

You might plan of doing this every year or so as the Portland mortar falls out. It probably will never fall out of the joints toward the front and high in the firebox where the temperature doesn't get over 600 degrees F. If matching the color of the mortar matters, you can add regular mortar coloring to the HeatStop and, with a little experimentation, probably match the Portland mortar color.

Best,
Jim Buckley