Thread: Three hole brick

I'm looking for opinions on the exposed three hole brick. The picture is taken looking up through the damper.

I called for repairs and Level II certification. The sellers brought in a sweep who gave them a letter stating:

Exterior condition of chimneys is fair. Interior flue system on both chimneys was very good and safe for having wood burning fires. Lower fireplace flue and firebox were in excellent condition. It appears that it has not been used very much. The three holed brick which are exposed in smoke shelf area are not a safety concern. Entire smoke shelf is solid masonry and perfectly fine to use as is. Upstairs firebox needed some minor tuck pointing which we performed. We also cleaned both fireplace flues. Both fireplaces are now certified and safe to use as is.

He did not do a video scan of the liners, apparently stating to the sellers that because the exterior looks so good there's no reason to do an video scan.

I sent the pictures to a CSIA Certified sweep I know who stated the fireplace is unsafe.

What's your thoughts?

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Originally Posted by Ken Rowe

I sent the pictures to a CSIA Certified sweep I know who stated the fireplace is unsafe. What's your thoughts?

Your sweep's statement parallels what the CSIA says - no open cores.

NFPA 211: Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances

2010 NFPA 211:

11.2.1.13 The inner surfaces of the smoke chamber shall be parge coated smooth, with an insulating refractory mortar, and not inclined more than 45 degrees from vertical.

11.2.1.9 Where a lining of low-duty fireclay brick (ASTM C27, Standard Classification of Fireclay and High-Alumina Refractory Brick), firebox brick (ASTM C 1261, Standard Specification for Firebox Brick for Residential Fireplaces), or the equivalent, at least 2 in. (51 mm) thick laid in medium-duty refractory mortar (ASTM C199, Standard Test Method for Fire Test for Refractory Mortars), or the equivalent, or other approved lining is provided, the total thickness of the smoke chamber walls, including the lining, shall not be less than 6 in. (162 mm).

I've never seen what is pictured, to be acceptable, or used as a rowlock stretcher in a fire box or smoke chamber. It is not solid. It is not properly grouted (wrong orientation) It is not lined. Perhaps Bob Harper or Ashley Eldridge or David R. or other might provide more.


7.1.5.2 Any space within the chimney below the level of the flue base shall be filled with noncombustible masonry material, mortar, concrete, or sand and topped with a wash or a cap that prevents the entry of moisture or creosote.

7.1.2.6 Corbeled or solid masonry shall be provided in masonry chimneys to support the entire perimeter of flue liners.

7.1.2.7 Where a flue is constructed of two flue liners without a spearation, three sides of each flue liner shall be supported entirely on corbelled masonry.

7.1.2.8 Corbels shall be made with solid units, and, where corbels are located on the walls of hollow masonry units, there shall be no fewer than three courses of solid masonry units below the corbels.

7.2.1 Construction.
7.2.1.1 Masonry chimneys shall be constructed of one of the following materials and laid with full, push-filled, head, and bed mortar joints:
(1) Solid masonry or solid, waterproofed, modular concrete blocks in nominal thicknesses but not less than those specified in Table 7.2, Column I
(2) Reinforced portland or refractory cement concrete in actual thicknesses but not less than those specified in Table 7.2, Column I
(3) Rubble stone masonry in actual thicknesses not less than those specified in Table 7.2, Column II

7.2.1.2 Reinforced masonry chimneys for residential-type appliances shall be permitted to be constructed of hollow masonry units not less than 6 in. (152 mm) nominal thickness, with cells fully filled with mortar.

7.2.2 Chimney Lining.
7.2.2.1 Masonry chimneys shall be lined.

Throwing it out there without knowing the specifics or circumstances.

Anatomy of Your Fireplace

R1003.5 Firebox walls. Masonry fireboxes shall be constructed of solid masonry units, hollow masonry units grouted solid, stone or concrete. When a lining of firebrick at least 2 inches (51 mm) thick or other approved lining is provided, the minimum thickness of back and side walls shall each be 8 inches (203 mm) of solid masonry, including the lining. The width of joints between firebricks shall not be greater than 1/4 inch (6 mm). When no lining is provided, the total minimum thickness of back and sidewalls shall be 10 inches (254 mm) of solid masonry. Firebrick shall conform to ASTM C 27 or C 1261 and shall be laid with medium duty refractory mortar conforming to ASTM C 199.

R1001.8 Smoke chamber. Smoke chamberwalls shall be constructed of solid masonry units, hollow masonry units grouted solid, stone or concrete. The total minimum thickness of front, back and side walls shall be 8 inches (203 mm) of solid masonry. The inside surface shall be parged smooth with refractory mortar conforming to ASTM C 199. When a lining of firebrick at least 2 inches (51 mm) thick, or a lining of vitrified clay at least 5/8 inch (16 mm) thick, is provided, the total minimum thickness of front, back and side walls shall be 6 inches (152 mm) of solid masonry, including the lining. Firebrick shall conform to ASTM C 1261 and shall be laid with medium duty refractory mortar conforming to ASTM C 199. Vitrified clay linings shall conform to ASTM C 315.




HTH.

Yep, ya'll covered it. Thickness, material, solid and parged. The code recognizes what's called "75%'ers" as sufficient to meet the std. for 4" nominal masonry even if not push-filled or grouted 100%. Thus, 4" nominal CMU block count as 4" of "solid" masonry while 6" + block do not unless fully grouted.

The fix is usually using a product called "Chamber Tech 2000" which is a special purpose parging refractory mortar with fiber reinforcing. UL gives it recognition as havign the same thermal resistance and 5" of solid masonry. Is usually applied and parged by hand. Long arms help. Other similar products on market.

I recommend you avoid the use of those terms "certification" and "safe". Anyone who "certifies" a chimney as "safe" is an idiot and a fool. An inspector can verify if an installation meets or fails a certain recognized standard-period. The contractor may recommend/ specify repair options that he assumes the liability for to meet the std.

Thanks for your assistance.

I knew it was wrong, but I keep running into these "qualified contractors" who don't really know their azz from a hole in the ground. I keep having to refer them to other contractors who actually know what they're talking about after the seller's contractors make statements like those above.