Glass Fireplace Flue, Really?

Why not a glass fireplace flue? Wouldn’t that look cool? High temperature glass exists that could withstand fireplace flue temperatures, so what if your new, high-end, modern home had a nice, custom fireplace with a see-thru flue? I don’t mean see-thru, I mean transparent. This is possible, and apparently it’s been done.

 Bertrand Goldberg, the mighty Chicago architect, designer of the iconic Marina City, designed a fireplace that had a glass flue in one of his early residences way back in 1941, so not only has it been done but it was done over 70 years ago. The idea challenges the basic properties of fireplace design, but advancements in materials and the sheer properties of glass make this concept not just doable but also a possibly efficient design. Think about it; a fireplace inside the house so the flue stays warm, a double-layer cylinder of glass where air insulates the inner glass and keeps flue temperatures high, inside the double glass you could push air so condensation doesn’t build up and you could see the circular motion of the smoke and heat rise within the flue. You would see it take off, sputter, heat up, cool down, but you will also see it soot up. Maintenance would be an issue for sure.

 Let’s take this one step further. Let’s create all of the internal components of the fireplace, hearth to ceiling, including the smoke chamber and curved breast all out of high-temperature glass. Let’s create the interior walls of the fireplace, where the firebrick goes, out of glass as well as the exterior shell, facing, out of glass. Air is a great insulator, so let’s keep the inside hollow and circulate calculated amounts of air through the assembly, let’s use warm air. We could keep the inside of the hollow, constructed fireplace structure clean and keep temperatures at a minimum by circulating the air with the help of a testing lab. It might be best to burn a gas log set of some kind to avoid extreme temperature changes. I’m sure glass doesn’t appreciate the shock value of wood-burning very well, but think about the possibilities. You could have a completely transparent fireplace and see all the inner workings of a fireplace from the floor to the ceiling.

Yes, building code violations are hurdles with the transparent fireplace design, but simply getting a glass flue on a masonry fireplace approved and past a local jurisdiction may be very possible with the right testing if you do your homework. With the right client, the right budget and the right design, Goldberg’s glass fireplace flue could absolutely be replicated if not improved on. Any takers?

 by Dane Batty



Why does smoke rise in a fireplace flue? It’s not just heat!

Sitting on the runway and cleared for takeoff I look out onto the wing and pray that the construction of the very thin-looking metal will, with all those exposed wires and tubes, structurally hold all of these people and all of their bags and all of their dreams knowing that the plane was built by the lowest bidder. It’s an unsettling feeling after being hit by that puff of jet fuel exhaust. Then I remember that demonstration in school that showed me that the shape of the wing doesn’t actually lift the airplane off the ground it pushes it off the ground. As a fireplace designer this makes me think of fireplace flues and how instead of warm air simply rising up through them they actually suck the warm air up and out of the fireplace. This sucking is called draft.

Draft in fireplace flues are a combination of HEAT in the firebox, PRESSURE in the flue and a TEMPERATURE DIFFERENTIAL with the outside air. I’m currently working on a custom masonry fireplace off the coast of Florida, and one obstacle for us is the temperature differential. The hot temperatures outside will create a smaller difference between the flue temperatures and the outside air and limit the draft needed to suck the smoke from the flue, so we have to compensate in different ways for the fireplace to draft well.

The fuel load in the fireplace is important as well. While a big fire that fills the inside of the firebox can overcome a fireplace and its flue the opposite is true as well. Problems can come when the fuel load is too small for the fireplace and its mechanical flue system. Having a very large fireplace with a small fire and fuel load may not be big enough to generate the heat needed for the large flue to develop the draft, so sizing your fuel load and your wood-burning grating with the size of your fireplace is an important part of the overall fireplace design. There are both upper and lower limits to the size of the fire in any fireplace.

As the airplane is coming down toward the ground, in a controlled way of course, it again uses the same aerodynamics as when it took off. It lands and pressures decrease against the wings. Similarly, when the fire is going out in a fireplace, the pressures decrease, the temperature reduces and heat is going away. This is arguably the most vulnerable time in the life of a fire in a fireplace. When the draft is diminished, but there are still heat and coals smoldering giving off smoke, it’s hard to make sure the smoke, heat and smell are sucked up the flue. This is where we have to compensate for the draft so we can eliminate the smoke coming into the room. A properly designed fireplace will take off, fly and land without problems, makes you feel safe (cause you’re literally playing with fire!) and gives you the warmth experience with your family. We like safe landings.


Why Hire a Fireplace Design Consultant?

A fireplace design consultant can work as a fireplace construction leader that supports the architectural design of the firebox provided by the architect and provides construction direction and specifications to all the trades included in creating custom masonry fireplaces in high-end homes, restaurants, hotels or business lobbies.

For instance, an architect can dream up the wildest fireplace design they and their client’s can dream, then a fireplace consultant will design the fireplace behind the wall with all the components, geometries, sizes and listed components that it takes to make the fireplace function without spilling smoke back into the room. This is a fireplace consultant’s specialty only limited by local building jurisdictions and construction budget.

The fireplace design consultant will also work with the mechanical engineer to make sure there is enough make-up air in the room for the fireplace to draw from (similar to a large kitchen hood) since air is necessary for the fireplace to draw. The consultant will work with the architect’s structural engineer to make sure there is proper support for the heavy fireplace and support for the inner fireplace components. The consultant will work with the electrical engineers and plumbing contractors with general layouts for them to create their supporting schematics for their equipment if the fireplace has electrical and plumbing products such as a motorized damper, draft inducement, signals to home computer systems, gas starters or electric ignition gas log sets. Some fireplaces have electric relay panels and some even have IP addresses!

A fireplace design consultant can work with the entire M.E.P. (mechanical, electrical and plumbing) team and provide leadership for the architect and contractor for proper design, construction, function and use of the custom masonry fireplace. The fireplace design consultant can provide alternate specifications depending on obstacles such as lightweight design for upper-story fireplaces, slim construction for limited space fireplaces, code-compliant construction for alternative installations, circuitous flue routings through floors and around architectural features, support for the architect with historical or very modern design or providing specifications on hard-to-find natural materials.

So if an architect or client can dream up a fireplace design, then there is a way to create the custom fireplace. Whether the fireplace is sleek and modern or if it’s 30’ wide, a fireplace design consultant will provide the leadership and guidance to construct it. This is why you hire a fireplace design consultant.

Dane Batty


Why Hire a Fireplace Design Consultant?

The new webpage is up now!

Dear interweb-goers,

It has been quite a long time coming, but the new webpage for Two Foot/Ten Foot went live this morning at 1am. With the help of Adobe Dreamweaver, web-hosting support, & the creative minds at Two Foot/Ten Foot, v1 is alive.

The biggest content changes come in the form of our Services & Toolbox pages. Our Services pages describe what we can do for specific clients, our Toolbox pages allow you to explore project photos, sample  drawings & generally enlighten your fireplace sense. The rest of the webpage has been rounded out with a slightly more aesthetically pleasing vibe.Version1.1 will shortly follow as there are still some changes to be made, & we will update our photos & content as our company and projects grow.

Enjoy the new web face of Two Foot/Ten Foot & let us know if there is something you wish to see on the webpage to make it more accessible to you. Click on the image below to check it out.


If you want clean crisp fireplace designs — Be Careful!

We’ve been looking at some great linear fireplace designs lately. Such as these super-sleek designs from Vizwerks which show linear installations with very minimal firebox enclosures. These types of renderings look great–and when constructed can make for some great photography.

Linear 2 ElevationLinear Elevation

Unfortunately, the day to day reality can be less rosy. If the air in your space is completely stagnant, then the fireplace may often look like it did in sketches or in Architectural Digest. But homes have breezes from doors opening and closing, people moving through the space, exhaust hoods and even the air rushing into the fireplace and up the chimney. This tends to give a messy flame and don’t get me started about carbon!

This photo came in recently of a custom fireplace installed in a public space. Even with a glass enclosure, soot is enforcing a dirty reality on their clean design. Now this contractor needs to re-engineer an existing structure in a finished and occupied building.


Sometimes it’s hard to hear the truth–that’s where your fireplace consultant can save you heartache.

Fireplace Therapy

Here is a home with some serious fireplaces, six and counting. When we were there last week almost all of them were burning!

Pool House

This fireplace was burning great! With the addition of some air and another eight feet of insulated chimney it’s a champ. Now if Dane can only find a plaster that can take the heat of clients who REALLY like to burn fires!

This big fella, in another part of the house, is getting A LOT of air and hopefully some additional chimney…

Great Room

Sparks are Flying

Flue Sentinel EIKI’ve seen people pay an additional $20K-$100K just to be able to burn a gas log in an open fireplace and still be able to shut the damper. If your pockets don’t stretch that deep for a site engineered custom fireplace control system–such a thing is available off of the shelf. There are a couple of outfits offering damper/gas ignition control panels to add a little high-tech to your hearth. The other option is a battery powered box that goes into the fireplace.

Gas Valves & Controls Located Outside of Firebox: These types of systems require locating a large (12” x 12” x 6”) electrical control panel outside of the firebox (typically within a wall or concealed cabinet) it also requires a hard connection to the home electrical system. These ignition systems typically rely on low voltage (24V or 12V), this requires the use on a transformer within the system to convert the homes voltage. The fire can be operated through a standard wall switch (requiring wiring and opening of sheet-rock) or even a remote control. The advantages to this type of installation are durability and reliability. Of course no power; no fire.Approximate Cost: $1,500.00–$2,000.00

Gas Valves & Controls Located Within Firebox: These systems require the least amount investment and construction. They are simply plumbed to the existing gas line in the firebox, there is a small sheet-metal control box (3 3/4” W X 5 1/2” D X 5 1/2” H) that is placed in the firebox next to the grating. This box has a thin layer of internal fiber insulation (typically 1/8”) and contains a valve, ignition module, power-supply and receiver. The box must be visible for the remote receiver. The system is powered using typically 4 AA batteries or a standard 110V electrical plug (requiring a power cord running out of the fireplace to the a wall socket!). These systems come complete with a hand-held remote control and are capable of adjusting the flame height using the remote. It is unclear how much operating time is available between battery changes but it would allow use of the fireplace during power outages. The control box, while black, may seem unsightly in the firebox. Another question is durability; being located within the firebox close to so much heat, plastic and electronics could be prone to failure. With that said, Skytech has been in business for many years and are established. They produce valves and controls for a majority of the fireplace and gaslog manufacturers. A system from another supplier would likely just be a re-branded Skytech system. Approximate Cost: $550.00-$750.00

The other option is to risk your eyebrows…


Linear Fireplaces on the March!

Speaking with a client in Lake Oswego recently, she told me that wanted to replace her drafty and inefficient open fireplace and/or gaslog set–but what she wanted aesthetically was a clean modern looking flame and not the big pile of worn out cement logs that was currently occupying very well turned out living room. She was torn between choosing something based on her interior  design goals and something that would be efficient and warm–oh and she didn’t want to spend loads of money! After a little research, it turns out that she can have that super-cool look that all the magazines are featuring these days.

A lot of the manufacturers are moving away from the country cabin look fireplaces to designer pleasing styles–and importantly for this market (and I’m sure all markets soon) efficiency and heating ability! Check out the Fireplace Xtrodinair Xtreme

Xtreme by Fireplace Xtrardinair

So while there is still the opportunity to choose fake wood in the firebox; there also some other cool firebox elements such as vertical ceramic bamboo poles or for the ultra clean look, nothing but granular glass media. There are lots of manufacturers doing this type of linear fireplace right now, but for me what makes this one neat is the ability to duct the heat to other locations in the home.

Fireplace Xtrordinair Heat Ducts

Fireplace Xtraordinair have been doing this for other style fireplaces for years but it’s nice to see such a fashion conscious product have at least some practicality built in. Plus, being built in Kirkland, WA; it’s practically local!