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Tar paper installed on roof surface.

Do-It-Yourself Roof Replacement:

Re-Roofing Part 2
Covering The Roof With Felt

Builder's Felt (Tar Paper) Is Used To Cover The Bare Roof Just After The Old Shingles Are Removed

In This Article:

The roof is prepared for shingles: Drip edge, Ice and Water Shield, and tar paper are installed, and a vent hole is cut at the peak.

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Skill Level:
2-3 (Basic to Intermediate)
Time Taken:
About 3 Hours
Project Date:
October 2000
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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.

It's also wise to install at least one row of rubberized asphalt roofing membrane, such as Grace Ice and Water Shield, which reduces the chance of roof leakage when ice forms at the eaves and water from melted snow builds up behind it. This scenario is commonly called an "ice dam".


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Installing The Drip Edge:

Installing new metal drip edge at the roof eaves.

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.

Metal drip edge overlaps at the corner of the roof.


Butt-joint between to sections of metal drip edge on lower edge of roof.

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. 

Applying Grace Ice and Water Shield to lower edge of roof.


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. Note that our single row of Ice and Water Shield does not meet that code requirement... but the roof is better than before. My local code does not apply to replacement roofing, but it would be a good idea to follow it anyway.

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.)


Patching Holes:

Thin flashing metal fastened over knot holes in roof sheathing boards.

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.

Small 3/4 inch knot holes were not covered with metal.


Installing The 15 # Felt:

Stapling roofing felt to bare wood roof sheathing.

We rolled out the tar paper and secured it with staples.



The hammer tacker is by far the fastest tool for this purpose, although an electric staple gun also works well, if you don't mind dragging an extension cord around.

Hammer tacker is used to staple the roof felt (or tar paper).


Piece of tar paper slipped over plumbing vent to prevent rain from entering.

Over the plumbing vent flashing, we slipped a scrap of felt.

This will 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.

Half of roof with tar paper applied, during re-roofing project.


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Scrap of tar paper lapped over upper edge of chimney flashing in roof.

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



Fastening The Tar Paper With Cap Nails?

November 2011: I just read something in a contractor's magazine about new building codes that might require bigger fasteners than the staples shown here. Essentially, this new code will require some type of cap nails, which are nails with a plastic disc under the head. Cap nails are commonly used to fasten foam insulation.

In my area there is no requirement to get a building permit to replace asphalt shingles, but if your area requires a permit, or if you are building a new structure, I would suggest calling your local Building Department and asking about special fastener requirements for roof underlayment.


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 chalk lines we snapped.

Using a circular saw to cut long narrow hole in peak of roof for ridge venting.


Long narrow hole in roof for ridge vent.

We made the hole a few inches shorter than the total length of ridge vent.

The hole ran almost the entire length of the roof.

Read more about cutting this hole and installing the ridge vent.




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.

Roof of small house with tar paper applied, ready for new shingles.


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.


More Info:
Tools Used:
  • Basic Carpentry Tools
  • Hammer Tacker/Stapler
  • Tin Snips
  • Circular Saw
Materials Used:
  • Drip Edge
  • Roofing Nails, 1-1/4"
  • Grace Ice and Water Shield
  • 15# Felt
  • Staples
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