With reference to your letter of July 27, 1988, regarding the application of Section 9.27. The roof in question consists of cedar shakes terminating in a back gutter formed behind the eaves fascia.
There is a general question of principle, which should be clarified before dealing with the specific questions raised. Article 9.27.1.1. of Section 9.27. states that "Roofs shall be protected with roofing, including flashing, installed to shed rain effectively and prevent water due to ice damming from entering the roof". As stated in an earlier appeal, we regard this as a performance requirement expected from the roof, and it does not necessitate every detail being included. The Code provisions merely indicate, in general terms, minimum steps that are considered necessary to achieve this performance, from a limited range of conventional materials. We would also emphasize that flashing is clearly a part of the roofing.
To deal with your specific questions:
A gutter formed within the roof is no different to a valley or other design feature, and the location is irrelevant. It may well be located behind the fascia as in this case, or at an intersection of different roof slopes well within the area of the roof. Thus the gutter in question clearly falls within the jurisdiction of the Code.
We note from the information submitted that the manufacturer of the gutter membrane states that it is incorrectly installed even for roofing. As indicated below, a gutter is a more severe condition.
There are no minimum slopes given for gutters, and this becomes a separate issue. Ideally every gutter should be laid to a fall, but this may not always be feasible, although a gutter should certainly not trap water. The Code is not specific on material selection for gutters formed within the area of a roof, and as these are locations which receive a concentrated discharge of water it must be assumed that they require a much higher standard than sloped roofs, both for materials and installation. It is not necessary for a shallow pitch gutter to be formed in metal, there is no reason why suitable membranes cannot be used, but the selection and method of installation must provide for the increased risk at such a location.
If our opinion is of any assistance, we do not consider the height requirement to be critical in this specific instance, as the upper edge of the gutter membrane is shown as extending to a reasonable extent above the top of the fascia flashing, and the portion of the membrane located beneath the bottom shakes is protected from the action of weather. The installation of the sheet lead would, however, be critical.
We consider the existing drain detail to be questionable in any event. It is unfortunate that the Code does not address electrolytic corrosion, but it should be reasonable for specialists to have some knowledge of such properties. There is already a good possibility for corrosion of the aluminum downpipe, immediately below the discharge of the copper drain. If the gutter is lined with lead the possibility would also exist for corrosion of the lead from the copper, but we regard the risk as low, certainly far less than that presently existing.
Eave protection is required under the provisions of Subsection 9.27.5., and we are unable to ascertain from the details whether or not the installation complies with these requirements. There would seem to be a difference between what is referred to in the Code as "eave protection" and the term as used in your enclosures.
Our difficulty with the eave protection is the impossibility of determining, from the details, whether it extends up the roof sufficiently to comply with Article 9.27.5.1. A bead of caulking as suggested would not change this position.
The Code does not require eave protection at the hips, but again this seems to be a terminology misunderstanding.
This question still appears to be directed at eave protection, but Article 9.27.1.1., as pointed out earlier, has much wider implications; a direct answer is therefore impossible.
J.C. Currie, Chairman
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