How can I kill Ferns?

Question

I find to my horror, that a colony of ferns has invaded the tight space between my roof slates and the (cemented) ridge tiles.

The root system of the ferns is tightly-bound, growing fast, and is prising the ridge-tiles off. I can (with great difficulty) get up to the ridge, but it's a hard job and somewhat dangerous. I can do it, and get there however

But I only want to get up there once! What can I put on the ferns to kill them stone dead with a single application please? I'd hate to do it, fail, and have to go up again... I'm nearly 81!

Answer 1

Try to find where it is starting at and just remove as much of the roots as possible. You get the roots it shouldn't come back. If you can't do that you might have to do a few applications of a weed killer. Since it seems to be growing out of the house you might not be able to get it taken care of in just one trip since you might not be able to get to the roots of it as easily or at all.

Answer 2

Bleach

Answer 3

Don't use bleach, use something with the active ingredient Glyphosate. Like Roundup, Or Kill Zall. Look for it in your local garden center. Roundup will kill the plant and it's roots. You can  put it in a garden sprayer and spray it from a distance. Make sure you soak them well, so you don't have to re-apply