Rumford Technical Discussion
Too Shallow!

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So you think our Rumford is too shallow? And you want to make it deeper? You like our Mercedes but you want to add jack springs and snow tires on it? We can do that, but it won't help the performance any.

We've had a lot of customers worried about how shallow the Rumford looks, especially before the surround and mantel are installed, but we've never had anyone complain that the fireplace is too shallow after they've had a fire.

We recommend looking at other Rumfords, talk to Rumford customers or at least look over the comments on our "endorsments" page. Then, if you really still think you want to make your Rumford deeper, first consider making it look deeper by adding a thicker or multi-layered surround. You can actually make the firebox deeper but it will add complexity because the firebricks may not course as well and you'll be forced to use the segmented throat system and a custom or chimney-top damper.

Click for larger image.

Other than looks, there is no need to use the surround to make the fireplace deeper. A 4" brick or stone surround is OK but if it's much thicker it may block some of the radiant heat and interfere with the streamline airflow across the throat. Consider mitering or layering a brick or stone surround so that right around the opening it doesn't project into the room more than an inch or two.

Other Rumfords with double returns

You might not be interested in efficiency but efficiency doesn't just mean you burn less wood. Think of it as performance. To me it's sort of like the pleasure of driving an efficient high performance car like a Mercedes compared with an old Chevy pickup. You may never drive the Mercedes at 150 mph but it still feels better at legal speeds. Efficient Rumfords look good and burn well. The shallow firebox heats the room better because the fire is up front and it "sees" more of the room. Another way to put it is you see more of the fire. A given size fire looks bigger in a shallow Rumford because it's more up front.


Subject: Too Shallow??
Date: Sun, 6 Mar 2005

I thought about that when building mine, but decided not to become unnecessarily ain't brok, so I didn't fix it!

But I did extend the hearth brick into the room to accommodate the possible sparks that would burn a wood floor, and fabricated a nice fire-spark screen for its front..

Don't mess with the design! It is the best, and the reason you wanted a 'Rumford' in the first place. Deal with in some other manner.

I studied Rumfords for more than 40 years before I gathered the nerve to finally build one. My hesitation was because of the un-American design. Young masons studied the Rumford too as they were preparing for their career, and were told of its great features. Then after graduating, they went forth into the world and built modified American monstrosities that their customers could use as places to put their indoor plants.


George MAurer
A Believer


Date: Tue, 27 Jan 1998
Subject: Re: My Big Rumford

Mr. Buckley;

Well, I specified and designed a big (72" x 54") fireplace. It was discussed with my client, photos shown etc. I even took pictures as it went up so they could see it (they were out of the country). Now they get back and don't like it. "It's too SHALLOW. How can we put BIG logs in it?"

They are having some expert come look at it to see if it is possible to "modify" it to make it DEEPER. (I think not). They built a fire in it and it worked beautifully (thank you, Count Rumford). So there's no excuse, except their aesthetic judgement, that it doesn't "look right". Seems the fact that it works, and radiates heat wonderfully, and is efficient, doesn't jive with their expectations of a more massive, deeper firebox.

Ever have this kind of problem before? Any possible modifications you could recommend? Any suggestions or stategies for me?

Thanks in advance,
An Architect

    To: Architect
    From: Jim Buckley

    Dear Architect,

    We sometimes encounter the "too shallow" objection during construction but rarely after first fire. We try not to oversell the Rumfords ("maybe you'd rather have a regular fireplace and you're not ready for a Rumford") and on jobs where we are dealing with the architect or decorator and are not in contact with the owner we try to make sure the owners are on board.

    But it sounds like you did that, and now here we are.

    In the end I would make it deeper. It's easy to make it look deeper by adding a surround with a deeper return. On this large fireplace you could add 8" to a foot of decorative surround out in front with no problem.

    Before doing anything, however, I would ask why the owner wants it deeper. How big a log does he want to burn? He should be able to burn four foot logs in it the way it is. One feature of a shallow fireplace is that a given fire is more up front and looks bigger than it would tucked back inside a deeper fireplace, so you may make the fireplace deeper and get bigger logs in it with no effect other than to waste wood.

    On a cautionary note, I would not rebuild the fireback at a slant as a way to make the box deeper at the hearth since in such a tall fireplace the slanted fireback makes it difficult to build tipi style fires with the logs standing on end (see Building A Fire In Your Rumford), and the slanted fireback will also tend to cast smoke forward and make the fireplace more likely to smoke.

    Ask your customer to call me and I'll ask if he has a car he would like to bring over so I can fiddle with it and make it burn more gas. Then at least he'll be ticked at me instead of you.


    Jim Buckley

And Another.........



I am going to build or have built a fireplace at my cabin this summer. I like the heat reflection qualities of the Rumford but I also like big fires. Since I am only up to the cabin maybe 10 times during the cold months I am not so concerned with efficiency, but it would be nice to have a big open fire that heats the room. Basically, the Rumford is too narrow for the type of fires of which I have grown accustomed.

I have an idea though! One of the principles of the Rumford is that the side walls project at a 45 degree angle from the line defining the fireplace opening. Now say you change that angle to say 55 degrees like the more conventional fireplaces that reflect heat back into themselves but have ample room for a big fire with an added difference in the side wall. That change would be to place the blocks that make the side wall at 45 degree angle to the fireplace open line successively (like a saw tooth). This would give you the reflective side walls of the Rumford with a deeper box for a fire and it wouldn't appear to change the box floor square footage to flue opening ratio by very much.

I would appreciate your thoughts.

Thanks, dc


    Go for it. I think we can make it work.

    More practically, however, I would just make the fireplace deeper and wider in the back if that's what you want. Thomas Jefferson did the same thing, so you could call it the "Jefferson Variation". You're right that the fireplace won't be as efficient but we've learned we can make even square cook-top fireplaces draw well by incorpotrating a few Rumford principles, like the airfoil throat the right size.

    Efficiency doesn't just mean you burn less wood, though. Think of it as performance. Like the pleasure of driving an efficient high performance car, you may never drive at 150 mph but it still feels good to drive to the grocery store. Efficient Rumfords look good and burn well. The shallow firebox heats the room better because the fire is up front and it "sees" more of the room. Another way to put it is you see more of the fire. A given size fire looks bigger in a shallow Rumford because it's more up front.


    Jim Buckley

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