EDIT: 1/21/13

We hired a professional mason to convert the two-sided fireplace into a single-sided fireplace.

We ended up interviewing about 5 people and getting bids from all of them. The guy we picked was by far the most knowledgeable. All of the others wanted to build a flat back wall (firebox). Only the gentleman we chose proposed something different, that being a Rumford Fireplace.

We are happy.


We have a 2-sided fireplace (open on both sides) which divides our living room and sun room.

The fireplace was built in 1925. We recently had the fireplace inspected and the inspector said everything looks good and it's OK to use.

One side had a wall of tempered glass attached to a metal frame. On the other side was nothing. I bought a glass fireplace door and installed it myself.

enter image description here

Last night we were having a fire and the tempered glass exploded (I know).

So I'm now thinking about doing the following project:

  1. Remove the metal frame that is screwed into the back wall
  2. Put up a solid brick wall on the back, thereby closing off that side and making it a 1-sided fireplace.
  3. ?

I am asking a question here because

  1. I have no experience with masonry
  2. I don't know whether this is a good idea from a safety perspective, although the risk seems pretty low since brick won't burn.
  3. It seems like double-sided fireplaces are relatively rare, so there I couldn't find a lot of information out there on this topic.

I'm a hacker and pretty confident in my abilities to read and follow instructions. The lack of masonry experience bothers me, but we're probably going to paint over the resulting brick wall, so it doesn't have to look perfect. Anyone think I will be able to do this project successfully? Can you provide me with a masonry howto or any tips?

EDIT: We have had the chimney and fireplace inspected by an off-duty fireman. He says that in its current condition, it is safe to use. My question, narrowed in light of that fact, is

  1. What kind of materials (brick, stone, etc) and mortar should I use to provide maximum heat and fire resistance?
  2. Any tips on where to get started as a completely green mason?

1 Answer 1


Did the transparent glass "back wall" explode because you added the front side glass doors and as a result the temperature in the fire box area went way up???

You need to consider carefully the airflow and draw requirements of the fireplace and the chimney that vents it out through the roof. Changing the design can really change the temperatures of the internal space!!

I would think that if you were to block off the far side with bricks that you may need to line the inside of the brick with special heat resistant fire bricks. Regular bricks could get extra hot and shatter too.

If you really need to have the front side glass doors make sure that there is a part of the design that permits the proper amount of air flow in around the sides of the door assembly for the chimney draw to work correctly.

  • The back wall shattered because I was burning a duraflame log along with some firewood. Mea culpa. I wanted to see whether the glass would withstand any heat, and it did not. The front doors fold in half and open like shutters to the side of the fireplace. The door manufacturer's instructions state that you're to leave them open while burning a fire, as they will shatter if left closed. Currently the fireplace does not draw extraordinarly well. There were some gaps in the back wall between the glass and brick which allowed smoke to leak into the room behind.
    – g33kz0r
    Commented Oct 7, 2012 at 16:33
  • If the chimney effect, which creates the draw of air up through the stack and out through the roof is not working well then you really should look into that before considering drastic changes to the fireplace design. You may also want to carefully investigate the dwelling area around the fireplace for evidence as to whether the fireplace worked well in the first place. If there is a lot of black soot on the walls, outside of the brick and on the nearby ceiling it could be an indicator that the fireplace draw was never very good!!. - Continued -
    – Michael Karas
    Commented Oct 7, 2012 at 17:55
  • Continued from above - Also take a look at the actual chimney. Is it partially plugged with a wasp nest? Does it have an obscured screen on the top? Is the top of the chimney below the upper level of the roof line by a large amount? All these could affect the draw of the fireplace.
    – Michael Karas
    Commented Oct 7, 2012 at 18:04
  • Thirteen years or so ago I had to build a new chimney onto my mom's old house because the old one from the early 1900's had used sand, horse hair and lime as the mortar between the bricks. There were fully open spaces between the bricks for the upper 1/3 of the chimney that really messed up the draw of the chimney and let hot gases and sparks out the sides of the thing way down below the roof line. (It was actually a wonder that the house had not burned becasue if it)!
    – Michael Karas
    Commented Oct 7, 2012 at 18:05
  • I'm fairly confident that 1) the draw is adequate as-is, but could be improved by increased suction created by sealing the the back wall. This is because before the abortive attempt involving the duraflame log, we had a few wood-only fires and it worked well with a minimum of smoke leak 2) We had the fireplace, chimney, and ash drop inspected by a fireman lieutenant who does inspections in his spare time. He pronounced the fireplace structurally intact and gave us the go-ahead to use it. I'm really interested in focusing my question on how to do this project, not whether it's safe.
    – g33kz0r
    Commented Oct 8, 2012 at 16:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.