Three distinct installation methods are used for custom steel doors and windows — and which method your project requires depends on your wall assembly, structural backing, and the specific HERRERO product being installed. Choosing the wrong method, or attempting to adapt the installation to a different method than specified, creates structural and water management problems that are expensive to correct. This guide explains each method, when to use it, and what makes each unique.
Method A: Block Frame (Through-Frame Screws)
Best for: Retrofit installations into existing masonry or concrete openings, applications where interior trim will conceal fastener locations, and situations where direct rigid anchorage to the surrounding structure is the priority.
In block frame installation, screws pass directly through pre-drilled holes in the steel frame and anchor into the surrounding structure — masonry, concrete, wood framing, or steel framing. The frame itself is the structural connection between the door or window unit and the building.
Installation sequence: confirm sill pan and WRB are installed; set unit onto sill pan with temporary shims; plumb and level starting at the hinge jamb (doors) or fixed jamb (windows); drive screws through frame into structure at 6–8 inches from corners, at hinge and lock points, then at maximum 16–24 inches on center; check reveals and operation after each series of fasteners; back-seal screw holes with compatible sealant and install finish caps or plugs; fill perimeter cavity with low-expansion foam or mineral wool; apply backer rod and sealant to exterior joint.
The main consideration with block frame: fastener penetrations must be carefully sealed to prevent water infiltration. And if fasteners will be visible on the interior or exterior face, finish caps or plugs must be specified and installed for a clean appearance.
Method B: Tab-Mount (Anchoring Tabs)
Best for: New construction and remodels where clean sightlines are desired — no fasteners visible on frame faces — and where structural backing can be added to align with tab locations.
Tab-mount uses factory-welded tabs on the exterior perimeter of the frame that anchor to the surrounding structure. The tabs are hidden behind the frame reveal once installation is complete — no fasteners are visible on the face of the frame from either the interior or exterior.
The critical requirement: structural backing must be present at each tab location. The shop drawings specify tab locations; blocking or backing must be added to the rough opening framing at those exact positions before the unit is set. Setting the unit first and then discovering there’s no backing at a tab location requires the unit to be removed — plan ahead.
Installation sequence: locate tabs per shop drawings and add structural backing at each tab location; set unit on sill pan with temporary shims; plumb, level, and square the frame (clamp if needed to hold alignment); fasten tabs to framing/backing starting at hinge/fixed jamb; verify reveals; fasten remaining tabs at maximum 16–24 inch spacing and within 6–8 inches of corners; re-check operation after each tab set; insulate and seal per standard procedure.
Method C: Nailing Flange / Fin
Best for: New construction with sheathing and WRB systems where best-practice water management integration is the priority. This method provides the tightest WRB integration of the three when executed correctly.
The nailing flange is a continuous laser-welded perimeter flange on the frame that is mechanically fastened to the sheathing and/or structural framing behind it. The flange overlaps the sheathing face, and the WRB, self-adhered flashings, and head flashing integrate with the flange to create a continuous drainage plane around the opening.
Installation sequence: cut WRB in an inverted “Y” at the head and tape the head flap up temporarily; install sill pan; dry-fit and mark flange holes; add solid backing where required; set unit on sill pan, shim, and center in RO; tack fasteners starting at hinge/fixed jamb mid-height; install remaining fasteners at 6–8 inches from corners, at hinge and lock points, then at 6–12 inches on center; integrate flashing by sealing flange to sill pan, applying self-adhered flashing over jamb flanges onto WRB, and installing head drip cap with WRB head flap lapping over it; insulate and seal.
The nailing flange method provides the best water management when integrated correctly — but a reversed flashing lap or unsealed flange corner will direct water behind the WRB. Follow the shingle-lap sequence precisely.
Choosing the Right Method for Your Project
HERRERO shop drawings specify the recommended installation method for each unit based on the project details provided during the ordering process. If the shop drawing specifies a method that conflicts with site conditions, contact HERRERO before installation — not after.
For questions about installation methods or to discuss your specific wall assembly with our technical team, contact us at doors@herrerodoors.com. For project estimates and to begin the ordering process, use Marco at quote.herrerodoors.com.
