Best caulk for roofing to fashia

I need to seal where the fashia touches the roof on 2 spots what is the best caulk to use ? Someone said Geo Seal or something I can’t find any info on it . Thanks

geo cell 2300

Use edge metal, not caulking.

This is a weird area, its where the valley ends and there is a small cavity I guess you would call it that goes 2 or 3 inches under the valley where the valley overhangs the main roof.

All I want to do is go up under that area and calk the edges where the shingles touch the bottom of the valley so if any water ever backed up under there it would not have a crack to get in.

Roofer told me to use GeoCel ??

you shouls sawzall the soffitt to get roofing up under it right.

This void you are referring to is somewhat normal.
By that I mean, sometimes it is not possible to get the shingle to form tight to the valley at the bottom (without breaking it).
Sometimes it is because of 2 different intersecting pitches, usually it is because the valley is not quite straight.

There should be no need to fill this void.
In fact it is probably best if you don’t fill this void…
Any water that does get under your shingles (probably none) will drain out of that void, the Ice & water shield protects the valley in this circumstance.
If you fill this void the water will have nowhere to go…
It can only back up until it finds a way out.
The Ice & water shield will protect the valley and eaves in this case also.
But if this keeps reoccurring eventually the nails will rust out and your Ice & water shield won’t work anymore.

Be very careful around this valley in the cold, you do not want to break the bottom shingle, it is one of the worst areas to repair and easiest to damage.

i like vulkem,
a tremco product.


The bottom shingle or it may be rolled roofing at the end of the valley has metal flashing under it for support and the roofing protrudes about 1/2" over the edge of the flashing,

The pc of roofing does have a slight chunck out of it from the heat wire I guess.
I do not want to FILL the gap or area under the valley just caulk the edge where the shingle that goes under the valley ends at the bottom of the upper roof deck or valley bottom.

It seems like if I dont this would be a direct route in. The valley is in fact 2 different pitches coming together and the valley ends short by 2ft of the roof edge. The main house roof is a 4/12 hip and the intersecting roof is a 5/12 gable roof.

A picture is worth a thousand words.
Sometimes more…

M-1 by Chem Link. No equals

I like any quality product that comes in a plastic tube vs. cardboard… they last longer in the back of my truck 'til I get to use them.


i like geocel i dont use much tar for anything except under the shingles sometimes thats about it i usually cleat all my secondaries too if they need nailed down with 1/2" metal strips and fold them upward

[quote=“gweedo”]i like vulkem,
a tremco product.


Tremco makes some great products.But take my advice never work for them.

I like Quad & Flexseal for silicones, Solar Seal is pretty good also.

I haven’t noticed much difference between polyurethanes.
Same with neoprene.

I like Solar seal… tripolymer has a nice ring to it. The Geo is nicer to finger.