I’ve been on a search for Irish Felt. Sample came today…it is not what I expected. It looks like, um, roofing felt that’s just a little bit thicker than regular roofing felt. Not as thick and soft as I thought it would be. This is 1/16″ thick, a little bit squishy/soft and a bit sticky with the bitumen. One side has a very light dusting of limestone powder. It is jute not flax and uses bitumen not pine resin/tar/pitch. In theory “Irish Felt” is made from flax with pine resins instead of petro products…I don’t know…I can see using it in some applications for Irish Felt–for example between worm shoe and keel or padding for tanks. Its more stretchy than regular roofing felt but not so stretchy that I could see it conforming nicely to sharp curves.
Here’s a pic of David holding the sample sent to me by the distributor:
Apologies, I know this post was some time ago, but were you ever able to source real pine-tar (not petro) impregnated felt?
And so sorry we are behind on our replies. We did use petroleum-based Irish Flax Felt. I believe it would be worthwhile to make my own and have a recipe for doing so with felt and pine tar. There is also a German company that may be able to produce a suitable mixture but I haven’t heard back from them. Fingers crossed.