Sealant Quantity Calculator
Length × width × depth straight to cartridges.
Inputs
Result
Formula
| Volume (ml) = length(mm) × width(mm) × depth(mm) ÷ 1000 | |
| Per metre = width × depth ÷ 1000 | ml/m |
| Cartridges = ceil(volume × (1+waste) ÷ pack size) |
200 m of joint, 10 mm wide, 8 mm deep, 310 ml cartridges with 10% waste: 16000 ml gross, 17600 ml with waste, so 57 cartridges; 80 ml per metre, 3.9 m per cartridge.
FAQ
Why not make depth equal width?
The sealant must move freely. Movement capability is rated as a percentage of width (say ±25%), and three-sided adhesion locks it in place so it tears from the base under movement. A polyethylene backer rod sets the depth and limits adhesion to the two faces, with depth about half the width to form the proper hourglass section. It is the most basic and most often missed rule.
Why do sites often run short?
Three omissions: the real joint run is longer than drawn (corners and odd shapes add length); tooling and masking consume sealant; and rework happens. Allow 10-15%, or 15-20% for complex façades. Also watch shelf life - do not buy the whole job at once.
Can structural and weatherproof sealants be swapped?
No. Structural silicone carries load and must be proven compatible with the substrates through adhesion and peel tests; it costs several times more. Weatherproof sealant only seals against water and carries no load. Using it to bond façade panels is a serious hazard - glass can fall out whole. They look identical, so check the product designation and test reports.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.