Lower Edge

The building codes in this area require the installation of an ice dam protection membrane at the lower edge of the roof to protect your home against leakage from water trapped behind an ice dam. The codes specify that the ice dam protection membrane should start at the lower edge of the roof and extend up the roof a minimum distance that is determined by both the width of the overhang and the type of roof covering that is to be used. There is a detail at the lower edge of the roof that may allow leakage even with the ice dam protection membrane installed. The area of concern is the joint between the roof deck and the fascia board or trim.

In many cases it is not possible to seal this joint with the ice dam protection membrane. The fascia board can be too low, the width of the joint can be up to 4 inches wide, the top edge of the fascia can be irregular or narrow. These and other things can make the seal questionable if it exists at all. In these cases the standard approach is to install a drip edge at the lower edge of the roof that spans over the joint and extends down onto the fascia. The ice dam protection membrane is next sealed to the upper flange of the drip edge. This type of detail is also used with one-piece, flanged gutters.

A problem can develop with this system if gutters without an integral flange are installed (two piece gutter). The back of the gutters is slid up behind the face of the drip edge or the gutter apron. The problem develops when there is an ice dam at the lower edge in the gutter and the water is able to back up between the gutter back and the face of the drip edge. This water is then able to leak in through the joint between the deck and the fascia. Leakage can occur through any size joint in this case.

There are two primary methods of sealing the lower edge when two-piece gutters are to be installed.

1. Extend the ice dam protection membrane down onto the fascia several inches. The gutter apron or drip edge is installed on top of the ice dam protection membrane and the back of the gutter is slid up between the face of the drip edge and the ice dam protection membrane that is on the fascia. In this case if there is an ice dam at the lower edge in the gutter and the water backs up between the drip edge and the back of the gutter the water will run out between the fascia and the back of the gutter.

2. Extend the ice dam protection membrane down into the gutter and seal it to the back of the gutter. The drip edge / gutter apron will be installed over the ice dam protection membrane to protect it. This solution of course assumes that the gutter is in place at the time of roofing and that the back of the gutter is clean enough to provide a good seal to it. When an ice dam occurs in this application the water is not able to get behind the gutter at any point. The gutter straps have to be removed and reinstalled but that should not affect the gutters performance if the gutter is properly installed and the back of the gutter is fastened to the fascia.

Our warranty against leakage from water trapped behind ice dams refers only to leakage that gets through the ice dam protection membrane. If water is allowed to move around, above or under the ice dam protection membrane, it is not covered under the terms of the warranty.

The costs and warranty coverage will vary depending on how this detail is completed. It is important to make an informed decision about how this area is to be done.

Reuse of existing gutters is often done if they are still in good condition and functioning as originally designed. However, it is important for the homeowner to know if the gutters are still under warranty from the gutter contractor or not. Several gutter contractors in the area (but not all) have had their warranties written to say that their warranties are null and void if someone other than the original gutter installer works on the gutters. Even to the extent of simply removing and reinstalling the gutter straps. It should be noted that neither of the previously mentioned procedures for sealing to a two-piece gutter can be accomplished without first removing the gutter straps. The homeowner is ultimately responsible for knowing the gutter warranty coverage, which may affect the best course of action in this area.

If the installation of a gutter is contemplated at a later date, it should be planned for at this time. The same would be true if an existing gutter is to be replaced at a later date since removing the gutter could damage the ice dam protection membrane depending on how the lower edge was detailed.

The joint between the fascia and roof deck can be several inches wide. Over time asphalt shingles can sag into the gap if they are not properly supported, thereby allowing water to funnel in. One solution to remedy this problem is to install a wide flange, heavy gauge drip edge to this area that both spans the gap and at the same time offers support for the shingles.

To summarize, it should be determined to what extent the joint between the fascia and the roof deck is a problem. Next, are the existing gutters under warranty and what kind of condition are they in? Are gutters to be installed now or at a later date? With this information one of our representatives can assist in determining the best course of action to take in dealing with this lower edge detail.