Low-Pitched Roof: Re-Roofing Part 2: Covering The Roof With Felt

By Bruce W. Maki, Editor

After the shingles have been torn off, there are several steps commonly taken to "dry-in" a roof. New drip-edge is usually installed, new flashing may be installed around roof penetrations, and roofing felt (also known as tar paper) is installed to prevent leaks while the shingles are installed.

Installing The Drip Edge:

After the roof surface had been completely cleaned of debris and all loose boards had been fastened down, we installed the drip edge (also called "edge iron") along the eave. We nailed the drip edge with 1-1/4" galvanized roofing nails.

At the corner, the drip edge along the rake (the sloping edge) is laid over top of the eave's drip edge and nailed.

Butt joints are made by overlapping the pieces a small amount and forcing them together. The aluminum bends easily.

Ice & Water Shield:

Next, the ice and water shield was installed. This 3-foot-wide strip is extremely sticky... once applied you can forget about peeling it off. Here Randy is carefully adhering the edge of the new roll. Then he pulled the release paper from the back and pressed the sheet in place.

Here in Northern Michigan, the local building codes now require an approved ice and water shield be installed up to a point three feet in from the outer wall. This is intended to prevent roof leakage from the inevitable ice dams that form when the snow melts in late winter.

This product is truly amazing. It literally seals around all nails that penetrate it, forming a water-tight barrier. It's expensive, around $60 a square, but far cheaper than the damage from a leaky roof. I once saw a large hotel building (that had a history of terrible ice dams and leaks) that was completely covered in this product before it was reshingled. They must have used two hundred rolls of ice and water shield. Whew! (I'll bet they got a volume discount.)

Hole Patching:

The larger knot holes in the roof were covered with aluminum flashing, which was stapled in place with a hammer tacker.  Smaller holes like these, just big enough to stick your thumb through, were left uncovered.

Installing The 15 # Felt:

We rolled out the tar paper and secured it with staples. The hammer tacker (right) is by far the fastest tool for this purpose, although an electric staple gun also works well.

Over the plumbing vent flashing we slipped a scrap of felt, to be removed when the shingles are installed.

The rows of felt are overlapped by a few inches. It only took about 10 minutes to cover this side of the roof.

At the chimney, a small piece of felt was lapped over the upper edge of the flashing.

Cutting The Hole For The Ridge Vent:

To allow the hot attic air to escape through the ridge vent we planned to install, we cut a thin strip of roof sheathing from each side of the peak. We simply set the circular saw blade to exactly the depth of the roof sheathing planks, and followed the lines we snapped.

We made the hole a few inches shorter than the total length of ridge vent. The hole runs almost the entire length of the roof.

When the second side was covered with felt, we let the top row cover over the peak, concealing the ridge hole. This will be cut out later.

The tar-papered roof is a logical stopping point for the day. This layer of felt is an adequate temporary roof surface that will stand up to moderate winds if stapled securely at the edges. Note how we placed bundles of shingles on the roof, in preparation for the next day's work.

See the asphalt roof shingles installed.

Copyright © 2000, 2005  HammerZone.com

Written November 1, 2000
Revised January 13, 2005