Fireplace Design & Dimensions

Can the opening size of a fireplace be reduced? Could the facing of the granite fireplace surround be made to cover part of the length of the opening: i.e. 29"hx48" wide, reduce this to 36" wide? We could use fire bricks to make the opening smaller.
How do we measure the size of the flue? We cannot tell by looking up past the damper as the walls are slanted. Do we have to get up on the roof? Thank you

Sue,
If you alter one measurement, all must be modified.

You need to get on the roof to verify the flue size. Be careful!

SIZE OF FLUE FOR:
Fireplace Opening Width 36"
Fireplace Opening Height 30"
Firebox Depth 16"
Rear Firebox Width 24"
Rear Firebox Wall Vertical Height 18-20"
Minimum Chimney Height 50'

Hello Ive built about hundred fireplaces , but i never built one outside ,I'm WORRIED about the draft the contractor has no prints but he wants it to be 36" box but only 8' tall .I don't want to built it wrong . can you help me ? thanks ted

Ted,
Sure. Read *all* of my articles about Fireplace Design. There are two or three critical articles. Pay very close attention to the table on this very page with all of the dimensions.

Tim,

I have a see through fireplace which I have come to realize since I bought the house is pretty but not practical. I've considered closing off one side and or raising the chimney height but would like to hear your opinion. This thing is a mess compared to the dimensions chart.

Thanks,
Keith

opening height 26" both sides
38" wide both sides
31" deep
47" from bottom of firebox to damper
12x12 flue
14.5' chimney height from the damper

Keith,
If you want a fireplace design that performs flawlessly, then you design a fireplace exactly to the dimensions in the table on this page. If this means getting out a sledge hammer to help you, then so be it. Sorry, but it was time for some tough love.

I am new to the north east. My house is about 20 years old. When I burn my firepalce smokes goes down into my basement. There is a metal opening on the freplaces floor that leads down to an door in the basement wall. Not sure why this is happening? Any suggestions?

Steven,
Please read all about backdrafting and makeup air here on AsktheBuilder.com.

Do you think a 46" W x 49" H x 29" D fireplace with a 16"x16" flue and a chimney >16' tall will draft properly?

If not, how should I adjust the fireplace dimensions?

Thanks

Jim,
What does the magical table above say? Hire a seasoned mason who builds fireplaces on a regular basis.

Am I glad I'm reading the information on this page. Question. I want to take out a smaller fireplace insert with doors & blower to an open woodburning fireplace 42" high 33" wide. When I started inquiring about an insert I encountered only inserts with set deminsions. Di I need to plan to have a fireplace mason buils this fireplace from scratch?. Advice please.

What is a concrete hearth for a fireplace?

I can't find information about constructing a fireplace with a 20" or 22" width. The smallest I've found is 24". Is this a function of aesthetics (people want bigger fireplaces) or it it that 20" fireplaces aren't advised?

Frank,
You need to do that unless you think you can rattle a bag of monkey bones and achieve the desired result.

Lawrance,
It is one made from concrete. The hearth is the horizontal surface immediately in front of the firebox.

John,
A small fireplace like that is virtually useless.

We are building a new home. We would like to include a fireplace that has a width of 20". Are there problems with this?

John,
None other than you will be burning twigs in it....

Is a vent less fireplace better for a home if you want it for heat comfort,and if it is natural gas will there be any odor or possibility of carbon monoxide being produced in the house. Where I want to install this fireplace is in a family room which is open to the whole house. Is there anything that I should be concerned about?
Thanks

I would like to build a fireplace that has a width less than 20". Information on your pages shows dimensions down to 24". Is this minimum based on aesthetics or is there a practical reason?

Jim,
There are many things you should be concerned about. You need to go read all of my columns about Vent-Free Gas Logs. Read all of the comments at the bottom of those columns as well.

John,
Practical. You will be burning twigs in a fireplace that small.

Hello
I have this problem : 2 weeks ago I've decided to add a fireplace on my living room . However my house is made out of cement so i installed a metal chimeny (6" pipe)and the height is 6 meters, also the measurements for fireplace is 24" X 24"
And the problem is that I still have smoke that comes out from the fireplace openinig .
what do you think is the problem and what is the solution .
Thanks

James,
Did you install the exhaust pipe exactly as the manufacturer said to do? Is the damper turned the wrong way or partially closed?

Hello
Thanks for the reply . I don't think so the person that I've got to do the project simply can't do anything and the pipe has a small curve to the outside of the house then up to the roof .
Thanks again

I have a serious fireplace problem! The fireplace has never drawn- smke gets into the room immediately. The chimney has been cleaned thouroughly to no avail, and I think the design is wrong. It is open on 2 sides, with the same size openings: 39 1/2# wide, 29# high, 35 1/2 inches deep. inside the top the fireplce slopes in on one side and the flue, which is set up about 8 inches and is 31 inches long and 5 inches high, which in turn opens to the chimney which is set up another approximately 2 feet, and then extends at least 15 feet to the outside. Any ideas why it wont draw?

Susan,
Use the table that is part of this column and see if the design is correct. The smoke chamber must also be right and that is not easy to measure.

Looking at building an open independant fire place to sit in a 1700mm opening of a wall at 750 depth. One side of the fireplace will have a glass screen the other will be open.

What sort of height would i be looking at for the height of the fireplace opening from base to flue to ensure of maximum draft flow to flue?

Gav,
Use the table I have provided. Extrapolate values where needed.

Hi. We are designing a fireplace for a client with a 42" width and 32" height. The problem is the depth. We're working with the 2000 IBC. All of it's guidelines make sense except one. It implies that a 20" firebox depth is the minimum acceptable depth. Is this true or is it really saying that the firebrick in the hearth has to extend 20" from back wall. According to accepted practice, a 16" depth is what we should have to create a proper draw, so are they saying that the firebrick should extend out past the firebox opening by 4"? If so, why is this necessary is we have a stone hearth extension?
Thanks!

Rob,
I can't possibly answer you. I didn't author the code nor can I tell you what was on their minds...... You need to show your inspector the BIA Technical Notes on this.......

I notice from your table of dimensions that there is a rather dramatic variation in chimney heights to accommodate fireplace widths, i.e. a 40-inch fireplace width requires a 13-foot tall chimney min. but yet a 42-inch fireplace width requires a 19.5-foot min. chimney--and then a 48-inch width drops to a 16.5-foot tall chimney. Can you throw some light on why chimney heights jump around like this?

Lynne,
No, I can't. I am not the engineer who did the calculations.

You responded t my prior question (feb 3) by suggesting I check the dimensions, which I did. THe height and width seem to be fine. THe depth is about twice what is recommended on your chart but this is a double opening fireplace, so it is hard to say what the correct depth should be. I looked at the masonry website you recommended but it was difficult to understand. They seem to suggest that a double sided needs 2 flues- ours has one.... could that be a problem? or can you recommend a fireplace design expert in LA to take a look? we have tried contractors and chimney sweep companies but they dont seem to know much.

Susan,
You might have to schedule a consult with me. This comment area is for quick answers.

Iam building a fireplace which is a see through, with openings on both sides of 72"x 48". The depth is approx 3Ft. The chimney will be 40ft tall. What is the proper size for the flu? Thank you

David,
Use the table in this column and extrapolate the values. You can also contact the Brick Institute of America to see if they have Technical Notes on two-sided fireplace design.

I would like to have a double-sided see through fireplace with both openings 48" wide and 30" high. From face to face, the depth of the fire box is 36". Will this 3work? What size should the flue be and how high the chimney? The depth of the firebox is flexible. Thanks

John,
You should go to bia.org and snoop around their Technical Notes section.

My fireplace is currently used with a gas fire. I am keen to use it to burn solid fuel, but not sure the dimensions will enable me to do this, or whether all the heat will go up the chimney rather than out into the room

Height = 48cm
Width = 52cm
Depth 40cm

Jill,
It needs to be inspected by a sweep to ensure it is rated to burn wood.

Hi - great column!

I want to extend the front of my fireplace. It is currently a brick front floor to ceiling and I want to build out the front 6 inches. What would I need to do to extend the depth of the firebox? It is a wood bruing FP but I intend to use propane.

Thanks for the help!

Johnny,
You need to extend it with something that will not burn.

is there a formula or advice on what the proportions should be a for wall to fireplace opening?

Emma,
Great question! I am very sure there is and that would be found in some basic or mid-level architecture textbooks. Something tells me the ratio will be near 1:15.

Is there a maximum height for a certain opening. I am designin a 32' tall flue, measured from the bottom of the fireplace to the exit, 2' above roof line. The opening is huge, 2 sides open totalling 18 square feet. I'm on the charts per IRC 2003 for an 18" dia round flue but the height chart only goes to 25'.
thanks
paul

i am fixing to build a 5 foot by 4foot by 4foot through i am using a 2by4 foot special damper from vestal manufacturing after i set the damper on top of thefire brick should i go streight up or cobble back over past the damper before i set the first flu liner

I am writing to you from Northern Iraq. I'm an Architect & a civil engineer, however, as fireplaces are not a common thing to build here, people have no clue about them and I want to build three in my house. I know something about it as I have studies and built them through my education in UK but that was some 25 years ago. Would it be asking too much if you could send me a proper design for a fireplace (openning, backfire, sides, flue and chimney). The house is very well insulated (built from thermostone), two stories with a sloped roof in a mountainous area (cold/snow), ceiling height in the ground floor where the fireplaces are is 3.00 meters and 2.6 meters on the first floor. The fireplace is built into the external wall with the braest on the outside of the external wall. The openning I have is 1.27 meters (50 inches) wide. Will have to line this with firebrick. The height will be your suggestion. It serves a room that is 9.00 x 8.50 meters. I do not like very high mantels....shoulder level or less would be fine.
I dearly hope that you could help me out as construction is at a halt awaiting my suggestion for how it should be built. I don't mind paying for your suggestions too.

Thanks fopr the troubl in advance.

Hello,

I need some fireplace advice and have never built one before.

Two questions:

1. the fireplace i'm building is highly custom in shape and will be cast-in-place concrete. My first question is does the concrete have to have any particular qualities for heat resistance?

2. the room is very tall 20'-0" (+/-) and we want to have a 1/4" steel accent plate that follows the width of the fireplace all the way to the ceiling. My second question is do we have to have special construction in place in terms of minimizing heat transfer where the meatl accent plate is? I'm cyrrently thinking about having a metal stud wall covered with fire rated gypsum as a substrate and then place the 1/4" steel on top of that.

Any advice or reference to artciles would be GREATLY appreciated.

Thanks!

Hello,

I need some fireplace advice and have never built one before.

Two questions:

1. the fireplace i'm building is highly custom in shape and will be cast-in-place concrete. My first question is does the concrete have to have any particular qualities for heat resistance?

2. the room is very tall 20'-0" (+/-) and we want to have a 1/4" steel accent plate that follows the width of the fireplace all the way to the ceiling. My second question is do we have to have special construction in place in terms of minimizing heat transfer where the meatl accent plate is? I'm cyrrently thinking about having a metal stud wall covered with fire rated gypsum as a substrate and then place the 1/4" steel on top of that.

Any advice or reference to artciles would be GREATLY appreciated.

Thanks!

Hi I bought a 50s house which has old fireplace but the rear wall of the fireplace only slants inwards for the first 3 rows of bricks from the base and then it is vertical. All firplaces I have seen have the whole rear wall slanting inwards which presumably pushes more heat out-it doesn't seem like our fireplace is pushing out that much heat. Im not sure but maybe it was modified before to fit a coonara etc? Does the angle of the rear wall affect the heat direction and if so how should I go about fixing it? Thanks

I am constructing a new house and want to make a fireplace in my house.Our misions are not well aware of the fire places.Please advise.

Yes I know I will be burning twigs in it but I have a fireplace that is 14" wide 21" high, depth 8", rearwall 9", rear wall height 15", a 30 ' outside chimney. It smokes badly, if I want to continue burning twigs, do I need to line the chimney ? Or revert to matchsticks? Help!!!!

Fireplaces - I have knocked out a small coal griddle fire that itself was part of a bigger open fireplace which had then been filled in. So now we have a big hole with the original brickwork. The rear wall slopes back from the floor to the bottom of the flue - so in effect no smoke chamber just a straight up chimney. I propose deepening the box to approx 50cms at hearth level which will rise to 54cms at the top of the opening due to slanting rearwall, but with no side narrowing to the rear and having a 81 x 81 cms opening - this seems to work at my fathers house - are these paramenters broadly ok?

We have an old 2 storey home c1838 with a fireplace that smokes. Can you make any suggestion to improve its drawing ability?
Dimensions:
F'place opening width:60"
F'place opening height:54"
Firebox depth:28"
Rear firebox width:60"
Rear firebox vert. height:54"
Chimney height: approx. 28'

We have a brick gas log fireplace built
across a corner of the living room. There is a vent that goes thru the outside wall. We would like to change
this into a woodburning fireplace and add a brick chimney up the outside wall
without having to cut thru the roof for
the chimney addition. Can this be done?
...a corner fireplace but with a chimney
angled to the side??
Jane




l

I have a wood fireplace in an apartment in NYC, with a clay liner. The flue is the right size for the firebox. Smoke roles out at the begining and end of the fire due to not enough air. Make up air has been recommended because we dont want to open up the windows. The make up air can not go into the existing fire box because we cant get outside to do it (too tall). We can put a window louver in and a fan. How much air would the fan be?

I'm building a chimney to accomodate a gas burning fireplace at the basement level and a wood burning pizza oven on the next floor up on the exterior. What are the regulations in sharing the same chimney construction. Note: I cannot direct vent the gas fireplace because there will be a room behind the gas fireplace.

i want to make a double firebox chimney for adjacent rooms...what should be its dimensions and what advice u can give,would it be good ????thx for ur time

WE LIVE IN LAS VEGAS I AM PLACING A FLAT SCREEN TV ABOVE A GAS FIREPLACE. THIS WALL IS SHEETROCK, THE OUTSIDE IS STUCCO. I WOULD LIKE TO CONCEAL THE WIRES (POWER & CABLE) ANY SUGGESTIONS SHORT OF GETTING A CONTRACTOR? PUNCH A HOLE NEAR THE SIDE AND GO OUTSIDE/ USE WIREMOLD...??

Maybe a strange question, but are the metal "pre-engineered" / prefabricated fireplaces with a metal flu comparable in operation (draft and efficiency) to an all masonry fireplace with outside air and glass doors?
thanks

i have an hopen fire plaçe but when im not using it i think that wind comes in to the house by the chimney do you think i should use a door on the fire place? please help .

I inherted this old house (built in 1915) it's in pretty good shape, for it's age. But I was checking out the furnace and water heater, and it had been flagged for not having a slanted flue? What does that mean and how can it be corrected ? Appreciate all the advice and help I can get. Thank you in advance

I saw an awesome chimney that was in the middle of a room, on a concrete plattform and only had the flue floating above it. I'd like to know if a chimney like that needs any special calculations since it has no walls around it.

I am building a fireplace which I want to have either convective heat from under the hearth air source drawing on the 30'X 30'X 10'H area across the building, or use a fan to draw the air. Or should I consider using under slab water heating with a flue or firebox heat exchanger? What are your recommendations and where do I get the efficient design info? Thanks LT

Our new fireplace was constructed with a 42" x 42" firebox opening and a chimney height (groud level to top of chimney) of only 14'. Our contractor says that they chimney height is not to blame, but we can't eliminate the smoking problem (can't use the fireplace). From the table above, it looks like the height should never be as much or more than the width of the firebox, and that the chimney should be several feet taller for our fireplace. Any feedback you could give would be greatly appreciated.

Have you built a 72" fireplace? if so what are the correct height and depth dimensions.

I would like to built a fire place but i am not sure of the dimensions of the box for the correct air flow can you send me the dimension... Pleaseeeee!

I am wanting to build an outdoor fireplace and was wondering what to build the firebox out of. I have a lot of stone but do I need firebrick or can I build totally out of the stone, how did they do it in the old days, that is what I want. A very natural looking fireplace and as I stated, it is near my patio and will be used only for decoration and heat in the cool fall days. Thanks

masonary chimney with two 12" flues that have been raised in heighth twice still do not draw. One flue is for a fireplace and one is for a wood burning cookstove. Ther is a constant downdraft.

We have built an outdoor fire place and are unsure on the height the chimney needs to be.
Our fireplace dimensions are:
Fireplace opening width 46"
Fireplace opening height 24"
firebox depth 16"
rear firebox width 38"
Rear firebox wall verticle height 29"
Nominal Flue size 9"x13"

Can you please tell me what height my chimney needs to be.

Thank you

I'm interested in building a fire place for the center of a post frame building. the building is 60x100x18'side walls,. Wanting to put a fire place big enough to heat it from the center of the structure. was thinking possibly 4 side openings with some type of metal pipes in the bricks and stones extending out of it on the sides so they could be used for cooking, etc. need to have a material list on inside liner stones or bricks needed, and the structure and how to build it. if you have any idea, I would appreciate it.

thanks Mark / Indiana