Inter-locking Shingles

How much can you tell about the age of asphalt/ fiberglass interlocking shingles and remaining service life? Here in North Dakota this is the preferred shingle because of all the wind we get. Obviously look for loss of granules and cracks, exposed matt, torn or missing pieces etc. I haven’t noticed any cupping or clawing ( tell tale signs of 3-tab and dimensional ) because of the inter-locking design. What say ye? What do you look for?

I usually ask the seller. I dont know what your life expectancy see on them is up there, but down here on a 3 tab, we only get about 14-16 years.

Take pictures and send them to me!

You are correct these shingles are difficult to inspect, look closely for the typical signs of an composition shingle breaking down. Historically these shingles have lasted longer on the roof than there expected life span here in PA.

You’ve identified all the usual concerns for any composition shingles.

The interlocking composition shingle really seems a dinosaur. Are you suggesting that you have any recent installations out there in Dakota? Cause I was definately thinking they are no longer manufactured anywhere.

I can only imagine its partly because the darn things lasted so long that the shingle manufacturer’s decided they needed something that looked prettier but had a shorter lifespan! Plus, nobody around here remembers how you were to have used that special clamping like stapler tool. I found two of those tools some years ago in the basement of a Roofing Company that installed them in the 1950’s.

There are old houses in this town where 40-50 year old installations are still visible! Granted many times these are roof sections facing away from the southern exposure. All happen to have been in the color white or started out that way. They are pretty much dark stained and have become a dirty gray now. Simply amazing that they still hold any granules at all. IMO.

Let’s start a movement to bring back this ugly shingle!:slight_smile:

Thanks for the input guys. Certainteed quit making the T-loc shingles years ago. And nobody makes a replacement like that shingle. They said it was a marketing decision…It did perform well, and even though it had a 25 year service life, it often out lived that by many years. Even they ( Certainteed )said that you could not tell what the remaining service life was by a visual inspection. It was either good at the time of the inspection or not. I guess that the countdown has begun in that for the most part they have only about 22 years left according to the manufacturer’s recommended service life on the newest installations.
Gerald Wilcox

They were just installed on a house down the street from where I live. Someone must still make them.


I suppose…but who? There probably is some in the system somewhere, the local supply house had left over inventory from years ago…not enough to do a house, and probably not the color desired. I guess I would be curious who still makes them, if available.
Gerald Wilcox

Here you go:

Ohh Canada !

Thanks Marc, from what I understood from Certainteed it was discontinued, and nobody was making them. That company seems to be very regional, but even so there it is. Too bad they’re not as available like they once were…
Gerald Wilcox

Last I knew, IKO still makes them…I have my opinion of IKO based on build & performance however if this what you want or need there you are!

Not sure. Certainteed still has the T-Locks on their website.