Air tight attic access port

[fyidiy]

For a well-insulated attic:

1) Install attic insulation baffles.
2) Install radiant heat barriers.
3) Use spray can foam to seal all wall joints, drywall seams, and upper floor ceiling attic penetrations.
4) All upper floor ceiling electrical boxes get covered with domes made air-tight with spray can foam.
5) Build a 1/4" plywood dam around the attic access port so blown-in insulation doesn't fall back down.
6) Install two feet of blown-in cellulose insulation in the attic proper.

Now, how to make the attic access port as air-tight and insulated as the rest of the project?

The access port is made up of two separate panels. The first bigger panel covers most of the port. The second panel covers a smaller hole in the first panel. The hole in the first panel is so insulation can be blown up above the access port.

Once the first panel cover is installed, insert the blown-in insulation hose up through the dirt bike inner tube "door" and fill up the void above the access port. Install the second smaller panel to cover the hose access.

Both panels are sealed with sill plate foam around their edges to act as gasket material.

Since the heads of the bolts can't be accessed once the panels are put in place they've been welded to 1/8" strapping.

Yes, the smaller panel was a little over engineered bolt-wise. Three bolts per side would have worked just fine. It was the first version of this build.

Photo #1 Long bolt being welded to the strapping. The electrical conduit keeps the bolt tight and square with the strapping.
Photo #2 Weld of bolt head and strapping.
Photo #3 How the bolt/strapping hangs down through the attic access port.
Photo #4 The dirt bike inner tube "keeper" for insulating above the access port panel.
Photo #5 Bolt/strapping welded and painted for use on the second smaller panel.
Photo #6 Large panel sanded, smoothed with drywall compound, painted, and ready to install.
Photo #7 Smaller panel with bolt holes and edging trim.
Photo #8 Both panels installed making the attic access panel air-tight and well insulated.