/ Field knowledge · IMC 802.5–802.6
Clearing the roof by 2 feet is not the whole height check.
Two different height checks. How high the Type L vent terminates above the roof is not the same as how much vertical vent sits above the appliance. Passing one does not pass the other.
Educational 2024 International Mechanical Code (IMC) 802.5 and 802.6 from Daily Code Talk. Confirm the adopted edition. Distinct from direct-vent (804.1) and mechanical draft (804.3). This is not a vent-size calculator. Type L is the listed oil-appliance vent — not a Category IV plastic termination.
- 802.5 Type L termination: at least 2 feet above the highest point where the vent penetrates the roof, and at least 2 feet higher than any portion of the building within 10 feet. Both. Measure the actual ridges, parapets, penthouse walls, dormers, and adjacent building portions — not a generic roof detail.
- 802.6: at least 5 feet of vertical height above the highest connected appliance flue collar. Measure from the collar, not the floor or the appliance base.
- 802.6 exceptions: direct-vent appliances, outdoor-listed appliances with integral venting, and pellet vents — each per the appliance and vent manufacturer. The exception moves the basis to the listing. It does not delete the venting basis.
On the set: flue-collar elevation on the schedule, a section from collar to termination, and a roof plan that shows every building portion within 10 feet of the cap. Do not leave final height to field adjustment.
The typical 2-foot roof detail is the comment
A cap that clears the roof deck by 2 feet still fails if a parapet or higher roof sits within 10 feet. Separately, a run that looks tall in plan can still be short of 5 feet from the collar. Check both in section.
Source: Daily Code Talk — IMC 802.5–802.6 · tool: Two height checks · cap: 802.4 listed cap · mechanical draft: 804.3 · existing chimneys: 801.18.
What to send
Appliance cut sheet (vent type and flue-collar height), roof plan or photos of nearby parapets and higher roofs, and whether this is Type L, direct-vent, or pellet.
If the termination is next to a parapet
Send the roof photos and the cut sheet. Masterbuild will say which of the two height checks still has no evidence.
Send Project Background+1 (786) 398-6940 · osmany.portal@masterbuildconsulting.com
Masterbuild provides engineering services under a written scope. Nothing on this page is project-specific engineering advice, a code interpretation for your project, or a representation about permit approval. Confirm the adopted edition. The 2-foot / 10-foot and 5-foot figures are 2024 IMC 802.5–802.6 education from Daily Code Talk for Type L vents — not a termination design. Direct-vent and pellet follow their listings. This page is not legal advice.