Rumford Fireplace - Instructions - Floor, Framing, and Inner Hearth

Oct 28, 2026

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Rumford Fireplace instructions detail the heat-focused design principles and provide construction guidance for a Rumford-style fireplace. The document covers key sizing relationships, including shallow firebox proportions and reflector geometry, and then proceeds with stepwise building direction. It specifies masonry hearth base support on adequate foundations, required widths and depths by fireplace size, hearth elevation for firebrick and brick extensions, and options for gas and outside-air intake. It also addresses clearances from combustible materials and outlines inner hearth construction using firebrick with refractory mortar, plus masonry backup thickness requirements.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages16

Reading Time40 min

AccessFree to download

Rumford Fireplace

Rumford Fireplace Plan Using Throat Sections

Rumford Fireplace Plan Using 1 Piece Rumford Throat

1. Foundation

2. Framing

3. Inner Hearth

# Rumford Fireplace Count Rumford,for whom the fireplacewas named,was born BenjaminThompson in Woburn,Massachusetts in1753.He spent much of his life as ahigh ranking official of the Bavariangovernment where he received his title,Count Rumford.Rumford is primarilyknown for the work he did on the natureof heat.Rumford wrote two essaysdetailinghisimprovements onfireplaces,one in 1795 and the other in 1798.Hewas well known and widely read in hislifetime and almost immediately in the1790's his “Rumford Fireplace”becamestate of the art worldwide and remainedso until wood burning fireplaces wentout of fashion (in favor of coal and later,gas fireplaces)in the 1850's. Fireplace by Buckley Rumford-Components from Superior Clay Rumford thought that fireplaces shouldbe alot smaller than they were in Englandin the 18th century.They wasted toomuch heat up the chimney and pulledtoo much cold air into the room. He also knew from his study of heat thatif the fireplace is shallow (ideally onethird as deep as it is wide)and the coving(or sides)are angled a maximum of 135degrees to the back wall,the fireplacewould reflect more heat into the room. # INSTRUCTIONSRumford Fireplaces Please leave the cover and four attached pages onRumfords and fire building for the homeowner. # Rumford Fireplace Plan Using Throat Sections | THROAT
OTHER DIMENSIONS
FLUE
FIREPLACE
SMOKE CHAMBER
DAMPER
G
D
F
B
E
A
SIZE
C
SIZE
(luasexG)
(DETIIXWIDTI
SIZE | | | | | | | --- | --- | --- | --- | --- | --- | | 36"wide
42"wide
48"wide
60"wide
72"wide | 20"x4"
23.5"x4.5"
27.5"x5"
10"x27"
10"x 34" | 9"x24"
9"x30"
9"x30"
10"x42"
10"x48" | 13"x27"x30"
13"x34"x 30"
16"x 34"x 30"
20"x50"x30"
24"x 57"x30" | 13"x13"
13"x18"
16"x20"
20"x20"
24"x24" | 30"
18"
36"14"
13.5"
32"-36"
13.5"
30"
15"
13.5"
21"
42"15"
38"-42"
30"
42"-48"
13.5"
18"
22.5"
48"16"
22.5"
30"
27"
45"-54"
13.5"
20"
60"
39"
24"
72"
45"-60"
13.5"
27"
31.5" | Dome-style damper wvith modified handle # Rumford Fireplace Plan Using 1 Piece Rumford Throat | OTHER DIMENSIONS:
DAMPER
SMOKE CHAMBER FLUE TII
FIREPLACE THROAT
F
D
E
G
C
A
(Basex G)
(AxF)
B
SIZE
(Frame) | | | | | | | --- | --- | --- | --- | --- | --- | | 24"wide
30"wide
36"wide
42"wide
48"wide | 24"x 12"
30"x 12"
36"x14"
42"x15"
48"x16" | 9"x24"
9"x24"
9"x 30"
9"x30" | 8.5x24"x 24"
13"x27"x30"
13"x27"x30"
13"x34"x30"
16"x 34"x30" | 8.5"x 13"
13"x13"
13"x13"
13"x 18"
16"x20" | 24"
12"
24"-28"
24"
12"
13.5”13.5"
12"
15"
30"
13.5"
28"-32"
30"
12"
30"
14"
32"-38"
18"
36"
14"
13.5"
30"
15"
21"
15"
42"
38"-42"
15"
30"
16"
42"-48"
22.5"
18"
16"
48" | ## 1.Foundation A solid masonry hearth base 4”thick should be supported on an adequate masonry foundation. ·For the 24"Rumford the hearth base should be at least 4'-0"wide ·For the 30"-4'-6"wide ·For the 36"-5'-0"wide ·For the 42"-5'-6"wide ·For the 48"-6'-0"wide ·For the 60"-7'wide ·For the 72"-8'wide From front to back the hearth base must be deep enough to support the firebox and chimney plus a hearth extension at least 20"out in front of the fireplace opening.In houses with rooms or crawl spaces below the fireplace,this hearth extension is usuallycantilevered and constructed of self-supporting reinforced concrete or“corbel slabs”supported by a masonry stem wall the same sizeas the wall surroun

FAQs

What should the hearth base be supported by in the Rumford Fireplace instructions?

A solid masonry hearth base 4” thick should be supported on an adequate masonry foundation.

How should clearances to combustible materials be handled?

Combustible materials should be kept 2” away from the outside of a masonry fireplace or chimney.

How is the inner hearth constructed?

Firebrick is laid on the masonry hearth base using refractory mortar to create at least minimum 1/16 inch joints, then backed up with solid masonry to ensure the firebox walls meet the required thickness.

Oct 28, 2026

Upload by Terk