Most homeowners considering an outdoor fireplace know what they want the finished product to look like — but don’t know much about what actually goes into building one correctly. Understanding the construction process helps you ask the right questions when getting quotes, recognize quality workmanship versus shortcuts, and appreciate why proper outdoor fireplace construction takes the time and cost that it does. This guide from VistaScapes Design & Build walks you through exactly how we build outdoor fireplaces in Tulsa from start to finish.
Step 1: Engineering and Permit
Before any ground is broken, outdoor fireplaces in Tulsa require a building permit from the City of Tulsa or the relevant municipality. We submit plans showing the fireplace dimensions, chimney height, footing design, and clearances from structures and property lines. The permit process typically takes 1–3 weeks. This isn’t bureaucratic overhead — it’s the reason your fireplace will be documented in the home’s building record, covered by your homeowner’s insurance, and legal at resale.
Step 2: Excavation and Footing Pour
A masonry outdoor fireplace is a heavy structure — a typical mid-size fireplace weighs 5,000–15,000 pounds including all masonry materials. This weight requires a properly designed concrete footing to spread the load across soil and prevent differential settlement that would crack the masonry above.
We excavate to a depth below Tulsa’s frost line (typically 18–24 inches) and size the footing to extend at least 6 inches beyond the fireplace footprint on all sides. A rebar cage is placed in the excavated area — typically #4 rebar at 12-inch spacing in both directions — and concrete is poured around it. The footing cures a minimum of 5–7 days (we prefer 14 days for larger fireplaces) before masonry work begins above.
Step 3: CMU Block Core Construction
The structural skeleton of the outdoor fireplace is built from concrete masonry units — CMU block, the same industrial-grade concrete block used in commercial construction. This core is what carries the structural loads, supports the weight of the chimney above, and provides the thermal mass that makes the fireplace function properly.
The firebox dimensions are critical. We follow the Rumford proportions or standard masonry guidelines that ensure the opening size, firebox depth, and throat opening are correctly related to each other — because these proportions determine whether the fireplace draws properly. Get the ratio wrong and you get a fireplace that smokes back into the seating area every time the wind shifts. Get it right and the fireplace draws cleanly in nearly all conditions.
Step 4: Firebrick Firebox Lining
The interior of the firebox — the area that contains the actual fire — is lined with refractory firebrick. Standard CMU block and standard mortar cannot withstand the repeated thermal cycling of a wood fire, which can reach 1,000–1,400°F in the firebox. Over time, standard materials would crack and deteriorate from the thermal stress.
Firebrick is a dense, refractory brick manufactured specifically for high-temperature applications. We lay firebrick with refractory mortar (also called high-temperature mortar), which maintains its bond strength through thousands of heat cycles. The firebrick lining is typically 2.5 inches thick and covers all firebox surfaces that are exposed to direct flame.
Step 5: Smoke Chamber Construction
The smoke chamber is the area immediately above the firebox opening where combustion gases collect before entering the chimney flue. This chamber must be properly formed and smoothly finished — any roughness or ledges in the smoke chamber creates turbulence that can cause the fire to smoke back into the outdoor seating area.
We form the smoke chamber with corbeled CMU block (each course stepping inward to narrow from the wide firebox below to the narrow flue opening above) and parge the interior smooth with castable refractory mortar. The throat damper is installed at the base of the smoke chamber — when open, it allows combustion gases to flow up; when closed, it seals the flue during periods when the fireplace isn’t in use.
Step 6: Clay Flue Tile Installation
The chimney flue is lined with clay flue tiles — rectangular or round tiles made from fired clay that are resistant to thermal cycling and the mild corrosive effects of wood smoke. Flue tile size is determined by the firebox opening area: the cross-sectional area of the flue must be approximately 1/10 of the firebox opening area for proper draft.
We stack flue tiles in the chimney column with refractory mortar at each joint, maintaining a slight offset (no more than 1 inch per tile length) if any bends are needed in the chimney run. Each tile joint is set with approximately 3/8-inch of mortar completely sealing the joint to prevent gas leakage into the chimney wall cavity.
Step 7: Exterior Masonry Finish
Once the structural work is complete, we apply the exterior finish. This is what most people see and what makes the fireplace beautiful. Options include:
- Full-bed natural stone: Oklahoma limestone, fieldstone, or sandstone set in full-depth mortar joints
- Thin stone veneer: Sliced stone adhered to the CMU substrate with polymer-modified mortar
- Manufactured stone veneer: Cast concrete products designed to mimic natural stone
- Brick: SW-grade exterior brick in running bond, Flemish bond, or other patterns
- Stucco: Fiber-reinforced Portland cement stucco in any color
Step 8: Chimney Cap and Spark Arrestor
The chimney is completed with a stainless steel chimney cap that covers the top of the flue tiles and incorporates a spark arrestor screen. The spark arrestor is required by code and prevents burning embers from landing on your roof, nearby structures, or landscaping. We use quality stainless caps that won’t rust or fail like the thin galvanized versions sold at big-box stores.
The Total Timeline
A complete outdoor fireplace build in Tulsa from permit submission to final inspection typically takes 4–7 weeks total: 1–3 weeks for permit, 1 week for footing cure, 1–2 weeks for structural masonry, 1–2 weeks for exterior finish and detail work. Projects are sometimes delayed by weather or material lead times. We provide realistic timeline estimates at the start of every project.
Ready to get started on an outdoor fireplace for your Tulsa property? Call VistaScapes at 918-779-1317 for a free consultation and quote.
