Felt roof repair compound

[ss]

I bought a tin of this , the grey gooey stuff with fibres in it, it was to put a line along where there is an overlap joint in the roof felt (shed) more as a precaution. So I have loads left and I wondered if it is likely to be suitable for weatherproofing the top edge of a wooden fence that has vertical slats, to stop rain soaking in to the end grain. Having used it for the shed roof I am thinking it would maybe add some extra life to the fence but dont want to waste my time if it does not offer some protection. The slats are mainly reclaimed wood from a neighbours fence that blew down so wood will be several years old.

[Bill Wright]

As with anything where the application has not been tested and documented by the manufacturer you'll just have to do it and report back in few years whether it worked.

Bill

[Dave Liquorice]

Assuming that these slats aren't in a place that is always damp or you have rain every day and they in free air and can thus dry out they'll last a long time as plain wood. Being ex fence presumably they are also treated (preservative) timber, last even longer.

The various rots that affet wood have a fairly narrow tolerance when it comes to how damp the timber is. Too wet (buried in normally wet ground), no good, too dry (out in the air) no good, this is why posts rot just above ground level, the timber dampness is just right between the two "no good" zones.

Putting a waterproof cap on might be a mistake as it'll trap water in the timber. How does it get under that cap? Capilary action from the sides.

[ss]

That makes sense, maybe best I leave alone.