Old-fashioned tar paper vs underlay paper

[Cancerman_777]

Hello everyone!

I'm in the process of replacing the roof and have noticed that the felt under the tiles on my house is completely different from today's underlay felt. The house is from 1951 and I'm quite sure it's the original roof that has been there until now. My question is whether this old type of underlay felt has stopped being produced? I'm fairly convinced that it doesn't degrade from sun, weather, and wind like the modern kind does. I simply suspect that it's real tar paper because they didn't have plastic-based products in 1951, right?

 

[Rickard.]

Tar has almost no advantages over bitumen (not plastic) except possibly that it was easier to maintain. Bitumen felt began to be sold by Trebolit and Mataki in the late 1910s and early 1920s, and by the 1950s it can't have been many percent of roofs that got tar felt, but it's possible.

Neither of them has the incredible properties you describe.

 

[Cancerman_777]

Tar has almost no advantages over bitumen (not plastic) except possibly that it was easier to maintain. Bitumen felt began to be sold by Trebolit and Mataki in the late 1910s to early 1920s somewhere, and by the 1950s it can't have been many percent of roofs that got tar paper, but it's possible.

Neither of them have the incredible properties you describe.

Bitumen, I didn't think of that! Absolutely right. It's probably bitumen felt, yes.

Do you mean that bitumen is not resistant to sun, weather, and wind?

 

[Cancerman_777]

There is something called asphalt felt as well. Could this be what I have as underlay felt?

 

[Rickard.]

There is something called asphalt felt as well. Could this be what I have as underlay felt?

Bitumen is the binder in asphalt, asphalt felt = bitumen felt = common underlay felt.

Could it be a "real felt roof" that has been reused as underlay? It's quite common and would explain a lot.

 

[Cancerman_777]

Bitumen is the binder in asphalt, asphalt felt = bitumen felt = common underlay felt.

Could it be a "real felt roof" that has been reused as underlay? It's quite common and would explain a lot.

Aha! So there's more or less no difference between underlay felt from the 50s and today's?

 

[Rickard.]

Aha! So there is more or less no difference in underlay from the 50s and today?

Oh, someone else should probably answer this, but in the 50s maybe YAL was used, and it is probably in all ways worse than even the cheapest available on the market today.