I have to repair a small area of siding in my home. I already have the siding material, however I need guidance on material sheating/insulation to put underneath the vinyl siding. I viewed the underlayment material underneath another section and it appears the material is a rubber sheating/insulation however I could not find that or another comparable item on homedepot.com. Any advice/guidance will be greatly appreciated!
It's difficult to tell from the picture exactly what you have there; the sheathing looks like individual boards. Is this an older home?
A very sticky, rubbery membrane is sometimes used to flash windows. It's essentially the same product that used on roofs to prevent water infiltration from ice dams. In any case, flashing a window correctly is very important, otherwise water can get in and cause damage.