Pick the sealant and the joint, and it tells you how far one sausage goes — then how many you need for the run, in full cases and single sausages. The arithmetic is the same one in our coverage article: a sausage holds about 36 cubic inches of sealant, and the joint cross-section decides how far that goes.
Silicone goes in 1/2" deep whatever the joint width, so the depth is fixed at 1/2". That assumes backer rod holds it there. Without rod the sealant sinks to whatever depth the joint happens to be and the number climbs fast.
Quick answers
How many linear feet does one sausage cover?
At the standard 1/2" depth: about 24 feet of a 1/4" wide joint, 12 feet of a 1/2" joint, and 6 feet of a 1" joint. Multiply by the case count to get a case: 20 for Seimeda, MF898 and MF899, 16 for DOWSIL 795.
Does the brand change the coverage?
Barely. Every sausage we sell holds within a hair of 36 cubic inches, so a foot of joint takes the same amount whichever you pick. What changes is the case: DOWSIL 795 is packed 16 to the case where the others are 20, so the same run comes out at a different number of cases.
How much extra should I order?
Ten percent on new work, closer to fifteen on a retrofit where the joint width varies along the run. Tooling loss is real and the drawing is not the building.
Does the backer rod change how much sealant I need?
Yes, and it is the biggest single factor. The rod holds the sealant at 1/2" deep. Without it the sealant fills the joint as deep as it goes, and a 2" deep cavity takes four times the sealant.
What diameter rod goes with my joint?
One size up from the gap, so it compresses in: 5/8" rod for a 3/8"–1/2" joint, 7/8" for 1/2"–3/4", 1-1/8" for 3/4"–7/8". A 1/4" joint takes 3/8" rod or bond-breaker tape, and a 1" joint takes 1-1/4" rod or larger — neither is a size we stock, so ask us. The calculator names it for the width you pick.
What to do with the number
Order it straight off the product page: every sealant is sold by the case and by the single sausage. The case is the better buy: a sausage in a case costs about $2 less than a single. From 20 cases of one sealant the volume price comes off in the cart automatically — the tiers are published here. When one more full case, or 20 cases, costs less than the exact mix, the calculator recommends the bigger order and says why. For a bigger job or a delivery past 50 miles, press Get Volume Pricing on the product, or call us with the quantity and the delivery ZIP, and we price it directly.
