Building a Masonry Firebox with Refractory Mortar Asheville NC
Product only, or product plus installation. Hardwood floors: All species and types, solid and engineered, unfinished and prefinished laminate floors, cork floors and bamboo floors; hardwood sanding and refinishing. Other flooring: Marmoleum, sheet vinyl, luxury vinyl V.C.T., rubber floors, cove base. Carpet: All carpet types for residential and commercial; custom area rugs, stair runners and outdoor carpets. Stone: Travertine, slate and exotic stone, granite floors, ceramic, porcelain, glass til
Homeowner Approved, Allen Tate Concierge Services.
High Point, NC
Formerly The Plywood Mart, Inc.; Mohawk® carpet, hardwood, laminate, resilient and tile flooring; Shaw® carpet, hardwood, laminate, resilient and tile flooring; Armstrong® hardwood, laminate and resilient flooring; Bruce® hardwood flooring; custom site finished hardwood floors (custom colors and designs available); Daltile® tile and stone; Crossville® tile and stone; Florida® tile and stone; Marazzi USA® tile and stone; Andersen® windows and doors; Marvin® windows and doors; Santa Cruz®
Homeowner Approved, National Wood Flooring Association Member.
Building a Masonry Firebox with Refractory Mortar
Source: MASONRY CONSTRUCTION MAGAZINE
Publication date: October 1, 2006
By Bob Rucker
Many fireplace masons are not familiar with refractory mortar, or they confuse the product with fireclay mortar. Masonry fireboxes are often laid in ordinary portland cement mortar, sometimes with a little extra cement or some fireclay added to make the mixture “fireclay mortar.”
This approach is not surprising since the major building codes have been unclear, inconsistent, or silent on the subject. The ICC codes – recently adopted in many states –require refractory mortar for the construction of fireboxes, smoke chambers, and flue linings, but a short while ago only the NFPA 211 code called for “refractory mortar (ASTM C199, medium duty).” The BOCA code required “medium-duty fireclay mortar,” the UBC just required that the “joints in firebrick shall not exceed ¼ in.,” and the CABO One and Two Family Dwelling Code did not specify the type of mortar or size of joint to be used.
The problem with using ordinary mortar is that portland cement can't take the heat. Oddly, portland cement retains its strength up to fairly high temperatures, but deteriorates as it cools down through about 600° F. Eventually all that is left of the mortar is the sand and fireclay, with no cement binder. The mortar has no strength and easily falls out of the joints, especially if they are wide.
Refractory mortar, on the other...
Click here to read full article from Masonry Construction