Duravent Stove Pipe DuraTech Elbow Strap, 5"

When two elbows are used to create an offset in a DuraTech chimney run, the angled pipe section between the two elbows extends laterally away from the vertical chimney centerline. The weight of all chimney pipe sections above the first elbow — which may amount to many tens of feet of pipe in a tall installation — bears down through the elbow connections at both ends of the offset section. Without a strap transferring some of that load into the building structure at the offset location, the full chimney weight above the offset is applied through the elbow joints as a combination of axial compression and lateral bending load. Over time this stress can cause joint loosening, elbow damage, and in severe cases joint separation. The elbow strap connects the offset section to a building structural element, relieving the elbow connections of this excessive load by sharing it with the building structure.

Additional elbow straps beyond the one included in the 5DT-E15KSS or 5DT-E30KSS elbow kit may be needed in two situations. First, when the offset pipe section between the two elbows is unusually long — a longer offset section has more weight and a greater lever arm that creates more stress on the elbow connections and may require more than one strap to adequately brace the offset. Second, when two separate offsets are installed in the same chimney run — each offset requires at least one strap, and only one strap is included in each elbow kit, so a second offset requires either a second elbow kit or a separate 5DT-ES strap. The DuraTech installation instructions for offset configurations specify the strap requirements for various offset geometries and chimney heights.

The elbow strap attaches between the DuraTech chimney pipe at the offset section and a suitable building structural element in the vicinity of the offset — typically a wall framing stud, rafter, joist, or other structural member that can bear the chimney load being transferred through the strap. The strap connects at one end to the chimney pipe body or a component at the offset, and at the other end to the building structure, providing a lateral brace that prevents the offset section from sagging and transfers a portion of the chimney weight into the building frame rather than through the elbow joints. The correct attachment location and method is detailed in the DuraTech installation instructions for offset configurations.

Yes. The 5DT-ES elbow strap is compatible with both 15-degree and 30-degree elbow offset configurations using the 5DT-E15KSS and 5DT-E30KSS elbow kits respectively. One strap is included in each elbow kit regardless of whether it is the 15-degree or 30-degree kit — the strap component is the same for both. When additional straps are needed beyond the one included in either kit, the 5DT-ES is ordered separately and applied in the same way regardless of the elbow angle used in the offset configuration.

Yes. The elbow strap requirement applies across the DuraTech chimney system range regardless of pipe diameter. The DuraVent installation guidance states that at least one elbow strap is required for each offset installation — this is a general system requirement that applies to 5-inch, 6-inch, 7-inch, and 8-inch DuraTech installations alike. The strap part number is diameter-specific — the 5DT-ES is specifically for the 5-inch DuraTech system, while different strap part numbers apply to the other diameter ranges. The 5DT-ES should not be used as a substitute for the correct diameter strap in 6-inch or larger DuraTech installations.

Installing a DuraTech elbow offset without a correctly installed elbow strap creates a structural deficiency in the chimney installation. Without the strap transferring chimney weight into the building structure, the full weight of all chimney sections above the offset bears through the elbow connections at the top and bottom of the offset section. Over time this sustained load can cause the twist-lock connections at the elbow joints to loosen, allowing joint separation that creates gaps in the chimney flue containment. Flue gas leakage at a separated joint is a serious safety hazard that can allow carbon monoxide and combustion gases to enter the building structure. The strap requirement is a code-compliance and safety requirement — omitting it also voids the DuraVent warranty for the installation.