Rolled Roof for a starter course

[Burt]

Hello All,

This maybe a stupid question, so I'll apologize for my ignorance ahead of time.

I live in the Buffalo, NY area. I am finishing up a new garage with a 6/12 roof. Looking at starting shingles soon (weather looks good for this weekend). Can I use rolled roofing as a starter course for the architectural shingles I am planning on using? My thinking is it would give me more protection (36" as opposed to one course of starter shingles) against water getting under the shingles because of ice damming. Would I still need a leak barrier like StormGuard or WeatherWatch?

Do the starter shingles have an adhesive which help hold down the first row of shingles? If so, rolled roofing would not have this, but could one use a roofing cement as a substitute?

Does this make sense? Or should I just go with the leak barrier and the starter shingles?

Thanks in advance for your advice, it is greatly appreciated!

[Rich]

Rolled roofing (Ice and Water Shield) should be used first - and should be ran up the roof to where it's at least 2' inside the exterior wall. I install it in all the valleys under the metal flashing as well.
On top of the I&WS I run a starter course of shingles - then business as usual.

[tooltroll]

Is your garage heated? No worries about ice dams if it isn't. I'd still recommend I&WS to be sure, though.

[grumpydasmurf]

Un-conditioned (heated) spaces do not require ice shield, but if it were my house I'd do it for the few extra bucks. Cheap insurance to be sure! However I don't think the original poster was referring to ice shield. I think he was referring to 90# mineral roll, this is not an acceptable starter course IMO.

My standard specification would include ice shield first from the gutter to a point 24" past the exterior wall. Then I would install the starter which would be a minimum of 7", but I usually get the 9" statrters. The purpose of the starter is to aid against wind up-lift at the edge of the roof.

You see, shingles are a self sealing system of overlapping materials. A standard asphalt shingle is around 12" high with a 5" exposure, meaning there is 7" of underlap AKA head-lap. (Sizes vary by manufacturer). However at the edge of the roof there is no overlapping shingle for the first row, so we must install what is essentially a half row so at any given point on the roof there is always actually 2 layers of shingles, not one layer.

Could you install a 90# roll? Sure, but you won't have the self sealing effect and will want to use a high grade caulk to act as an adhesive. Would you be to manufacturer spec? No probably not and you risk voiding your warranty due to improper installation.

Please follow all building codes and manufacturer guidelines in installation of any materials and please always act safely while up on a roof.