How Much Should Roof Sheathing Overhang

I ve trimmed my roof sheathing to run between 5 8 and 3 4 over the sub fascia.

How much should roof sheathing overhang.

This is to just enough to cover the 3 4 x6 actual fascia. Now that i ve modeled what i was going to build i decided i need a piece of molding to break up the plain look of just the fascia trim plank. The edge of the shingles should hang over a roof between an inch and an inch and a half or between a half inch and three quarters of an inch if drip edge flashing is installed. Measure up the rafter 45 3 4 inch from the cut end of the truss tail and snap a line along the trusses.

Drip edge varies in dimensions but typically the flange that nails to the roof surface is about 2 5 wide and the vertical edge that directs roof runoff down and away is about 1 5 in depth. However the suggested width of an overhang is between 12 and 18 for eaves and no more than 8 for rakes. Some slight overhang is recommended in conjunction with a drip edge flashing to prevent water from getting under the roofing and onto underlying wood. Overhangs can vary from a few inches to a few feet depending on preference.

That said overhangs can extend as far as 2 without the need for external supports. Thickness will range from 3 8 to 3 4 inch depending upon local code. This indicates the upper edge of the first row of roof sheathing leaving enough overhang that the subfascia and fascia will tuck neatly underneath when the time comes. Too little can allow water to seep into rake or fascia boards.

Metal is usually installed on rafters or strip sheathing rather than the solid decking used under other materials. It is at 45 3 4 in. When ordering the sheathing divide the total number of square feet of roof surface by 32 square feet a 4 x 8 panel and add an extra 15 for waste. Too much overhang and the shingles could blow off in high winds.

The drip edge also gives us a nice straight edge with which to align roof shingles slates or other roofing material.