To Back Fireplaces Fireplace Design Details

I am referring to the interior wall surrounding the firebox, which is drywall. The stone facia was removed and replaced with the drywall. The actual exit size is only 40 square inches. If the top of the chimney terminates in a square or rectangular flue tile, the fireplace is probably a masonry one. The easiest solution was to punch a hole in the brick hearth (fireplace floor) nearest the furnace or boiler, route a metal duct through the flue, and brick up the mouth of the affected fireplace.

We also raised the mechanical flue’s connection to the chimney in the fireplace throat so that it didn’t turn so abruptly into the flue.

I to understand that if we have back to back, non see through fireplaces, this may work?

Also, the approximate cost of having a sealed double sided gas fireplace?

Build firebox side and back walls at least (≥) 8 inches thick, including the lining, if using firebrick that is at least (≥) 2 inches thick or if using other approved lining material.4.

Build a hearth extension for a masonry fireplace at least (≥) 20 inches in front of the firebox opening and at least (≥) 12 inches to the side of the firebox opening, if the firebox opening is (≥) 6 square feet or more.4.

The hearth extension size is often the same as for a masonry fireplace.
Would removing the gas line be needed?

What do the burn patterns look like?

One is on an outdoor porch, the other in a master bedroom. Any outdoor fireplace may smoke in a breeze so shelter the fireplace from the wind, build the chimney as tall as you can and build the fireplace opening a little lower to improve draft.

Step by step how to build a fire back.Making Fireplaces Functional Again – Back To Back Masonry Fireplaces

They can either be placed on the floor of the hearth and just leaned against the back wall of the fireplace or secured to the back wall with supporting braces to keep them from sliding.

This would act as an insulator and as well stabilze the flue. Two 3/16-inch by 1-inch (5 mm by 25 mm) straps shall be embedded not less than 12 inches (305 mm) into the chimney. Each strap shall be fastened to not less than four floor ceiling or floor joists or rafters with two 1/2-inch (12.7 mm) bolts.

Masonry fireboxes shall be constructed of solid masonry units, hollow masonry units grouted solid, stone or concrete. The width of joints between firebricks shall not be greater than 1/4 inch (6.4 mm). Installation of steel fireplace units with solid masonry to form a masonry fireplace is permitted when installed either in accordance with the requirements of their listing or the requirements of this section.

The firebox lining shall be encased with solid masonry to provide a total thickness at the back and sides of not less than 8 inches (203 mm), of which not less than 4 inches (102 mm) shall be of solid masonry or concrete.

The firebox of a concrete or masonry fireplace shall have a minimum depth of 20 inches (508 mm). The throat opening shall not be less than 4 inches (102 mm) deep. The fireplace throat or damper shall be located not less than 8 inches (203 mm) above the lintel.
Masonry fireplaces shall be equipped with a ferrous metal damper located not less than 8 inches (203 mm) above the top of the fireplace opening.

Smoke chamber walls shall be constructed of solid masonry units, hollow masonry units grouted solid, stone or concrete. The inside height of the smoke chamber from the fireplace throat to the beginning of the flue shall not be greater than the inside width of the fireplace opening.

Where the inside surface of the smoke chamber is formed by corbeled masonry, the walls shall not be corbeled more than 30 degrees (0.52 rad) from vertical.

The minimum thickness of fireplace hearths shall be 4 inches (102 mm).
The minimum thickness of hearth extensions shall be 2 inches (51 mm). Hearth extensions shall extend not less than 16 inches (406 mm) in front of and not less than 8 inches (203 mm) beyond each side of the fireplace opening.

Codes are organized by jurisdiction to help you understand which regulations apply to your project.
It’s always better to use the smaller flue size when you have two choices. Taller chimneys draw better than short chimneys of the same flue size.
The bottom of the damper should be a minimum of 8 inches above the top of the fireplace opening. If your damper is not at least 8 inches above this spot, you will have smoking problems for sure!

The best mortar for firebrick is fire clay. Fire clay is a fine powder you mix with water to the consistency of gravy. They want the opening to be 60 inches tall. The fireplace opens outdoors to patio. We’d like to reduce the size of the fireplace opening (currently 25″ tall x 40″ wide to 20″ tall. We do not want to put in gas insert. Fireplace is masonry w gas/gas logs.
Is it possible to reduce the size of the fireplace opening? I try and light a fire, there is air blowing down the flu and the smoke goes back into the house. Does the top of the chimney need to go higher than the fished area on the 3rd floor? The opening is presently 52″ wide, and the thing doesn’t draft well at all. It’s a 2 story house, and the chimney is about 30′ tall. The additional depth might be 8″ or so. Is it safe or even possible to put a fireplace in the middle of the house? About how much would it cost to get the fireplace put in and the vent out the roof? One leaks water into the firebox fairly heavily when it rains. This unit and the other unit both spill smoke when burning a fire. Looke at the damper and the bottom flat area of the damper is only 3 inches above both fireplace openings. Pleas advise what details would be needed prior to your consult and the fee associated with your time. The dimensions of the opining for the fireplace on my wall unit is 19″wide by 16 3/4 tall.
I will abandon the restoration process if this the case. Sorry about my bad use of technical expressions in this question. If you’re buying a pre-made metal fireplace, it should have the correct smoke chamber, etc.
Traditional smoke shelves force the smoke to change directions, and can create swirling and other effects that conspire to mix air in ways that interfere with draw and allowing the smoke to leave cleanly.

You feel a little from direct exposure to fire, and the rest bangs around in the box and literally heads straight up the flue.

Rumford fireboxes are generally taller than they are wide, or at least close to square. That said, you’re the ideal candidate to build one and see how it works!

How many doctor’s who practiced medicine for 50 years prior to 1950 thought cigarettes didn’t do damage and morphine was perfectly ok to give a toddler for a cough?

Thanks for your question, and all the best.
You might take a sample of each of them to a local brick supplier and pick their brains. But there’s no way anyone is likely to say ‘sure, use this’. and as long as you’re okay with the possibility of them failing spectacularly after 20 hot fires, and you’ve gotta break down and redo it with firebrick.

Sorry we can’t be of more help on this; we rely on our brick vendors to be the knowitalls on things like this!

There’s nothing you’re really going to do, in my opinion, to easily make that thing stop letting your heat out. With so much surface area being warmed it stayed warm all night. The opening is now 30 inches wide and 29 inches high. I suspect that the biggest problem is the flue that is clay tile and approximately 8 x 12. I put a chimney top swing damper on it. Certainly the flu size can be a factor, and yes, the construction of the smoke shelf, how easily smoke can flow up and out.

So that starts to speak to the other reasons, which relate to temperature differential, and pressure.
I have a few questions, and then would suggest a really simple test, one that you’ve maybe already done. Does the stack go through ‘attic’ space of any kind, and/or do you even have an attic, or is it cathedral ceiling?

We’ve seen many times where the only good solution was to, for instance, extend the height of the stack to where physics just flat made the draw go up the stack, and no longer back into the room.

Let me know if you’ve done any experimenting with makeup air and what the relative heights look like.
Problem is, a massive, cinder block fire box. Monday to shape the firebox and install firebrick. I have several old homes (ca.200yrs old) as well as modern.
The old homes have lots of fireplaces in them. I would like to have something done to make them efficient and beautiful. Also have several old log cabins from pre civil war era. The reality is, there is no such thing as efficient with an open firebox, woodburning fireplace. The fuel consumption is also cut far back and in lockstep to the flow reduction.
Dampers shall be installed in the fireplace or the chimney venting the fireplace, and shall be operable from the room containing the fireplace. This table does not cover all requirements, nor does it cover all aspects of the indicated requirements. The total minimum thickness of front, back and side walls shall be 8 inches (203 mm) of solid masonry. The inside surface of the smoke chamber shall not be inclined more than 45 degrees ( 0.79 rad) from vertical when prefabricated smoke chamber linings are used or when the smoke chamber walls are rolled or sloped rather than corbeled.

Where the fireplace opening is 6 square feet ( 0.6 m2) or larger, the hearth extension shall extend at least 20 inches (508 mm) in front of and at least 12 inches (305 mm) beyond each side of the fireplace opening.

Two such ties shall be installed at each bend in the vertical bars. Straps shall be hooked around the outer bars and extend 6 inches (152 mm) beyond the bend. The projection of a single course shall not exceed one-half the unit height or one-third of the unit bed depth, whichever is less. Where the chimney offset is supported by masonry below the offset in an approved manner, the maximum offset limitations shall not apply.

Construction of masonry chimneys as part of the masonry walls or reinforced concrete walls of the building shall be permitted.
The net free area of the arrestor shall not be less than four times the net free area of the outlet of the chimney flue it serves.

The arrestor screen shall have heat and corrosion resistance equivalent to 19-gage galvanized steel or 24-gage stainless steel. Openings shall not permit the passage of spheres having a diameter greater than 1/2 inch (13 mm) nor block the passage of spheres having a diameter less than 3/8 inch (10 mm).

The spark arrestor shall be accessible for cleaning and the screen or chimney cap shall be removable to allow for cleaning of the chimney flue.

Factory-built chimneys or chimney units listed for installation within masonry chimneys. Pellet vents listed for installation within masonry chimneys. Section 1003.11.1, the chimney shall be plainly and permanently identified by a label attached to a wall, ceiling or other conspicuous location adjacent to where the connector enters the chimney.

Only enough mortar shall be placed to make the joint and hold the liners in position. The masonry wythes shall be at least 4 inches (102 mm) thick and bonded into the walls of the chimney. Square chimney flues shall have a minimum net cross-sectional area of 1/10 of the fireplace opening. Rectangular chimney flues with an aspect ratio of 2 to 1 or more shall have a minimum net cross-sectional area of 1/8 of the fireplace opening.

The height of the chimney shall be measured from the firebox floor to the top of the chimney flue. Cleanout openings shall be provided within 6 inches (152 mm) of the base of each flue within every masonry chimney. The height of the opening shall be at least 6 inches (152 mm). Chimneys located entirely outside the exterior walls of the building, including chimneys that pass through the soffit or cornice, shall have a minimum air space clearance of 1 inch (25 mm).

The intersection of the cricket and the chimney shall be flashed and counterflashed in the same manner as normal roof-chimney intersections. I have had good success in past with see-through fireplaces. Architecture, masonry fireplaces on exterior walls are problematic. The idea that you can just cut out the damper and parge the smoke chamber greatly under represents the amount of work need to convert a masonry fireplace from one-side to two-sided.

I would like to cut out the other side of the chimney (in our dining room) and replace our current stove with one that has two sides.

The back of the fireplace goes through that wall and is enclosed in a floor to roof “bump out”. The wall is now an inside wall due to turning the screened in porch into a 3-season room and the bump-out is in that room.

The current fireplace does circulate warm air into the room. All gas fireplaces are manufactured fireplaces and cannot be modified, so there’s nothing you can do to make the existing one see-through.
The depth from the inside wall face to the outside wall face is likely deeper than any gas see-through available, making for at least an awkward (if not impossible) installation.

As you mentioned, the heat differential is a factor. A fan was also installed to help blow out the heat. The glass was never put in place and the screens are still wrapped. I still want to use the blower for heat. Manufacturer says we can’t build next to the end glass panel even though it’s fixed, because some heat does escape through the glass. No, you do not have any other options other than replacement.
The brick chimney goes into the basement where there is also a fireplace. The furnace room is on the other side of the basement fireplace. Would this be effective in allowing heat into the rear side room?

Drywall and Framing around Masonry Fireplace

Or will brick warm up enough to provide any heat into that room?

I don’t think that it was just the heat riding up the surface of the brick.
The study houses the fireplace right now with the formal living room side just being sheetrock. I want the formal living room to have the fireplace instead of the study. We want to close off the fireplace on the master bedroom side. I would have to know whether it is a manufactured or masonry fireplace, how big it is and what the finish material is on each side.

Masonry Fireplace Inspection