facia/slate sealant

stewie1098

Just put up lots of wooden facia on slate roof. gaps between old boards was filled with mortar mix. Going to fill with sealant, which must be paintable (brown). Looking at Toolstation, they do a acrylic caulk, but also a polysulphide sealant in brown. Which is best- or better using another brand.?

also would it be best to undercoat first, one gloss coat. add sealant and then final coat?/Is this best order.

thanks.
stew

southcoastrgi

wood is flexible & will move to a certain extent, a mortar however isn't so it will crack & fall out so really it's the wrong thing to use for filling a gap in wood.