Connection and Sealant


For the connection we use galvanized plastic (PP) capped Silo bolts in Grade 5. In general the position of the plastic capped head of the silo bolt is every time inside, the washer and the nut are every time from outside. Use ONLY silo bolt for fixing the tank parts together. For mounting the tank sheets are used 5 different bolt lengths.

These are:
1“   = 25,40mm – blue protecting cap
1 ¼“= 31,75mm – yellow protecting cap
1 ½“= 38,10mm – red protecting cap
1 ¾“= 44,45mm – green protecting cap
2“   = 50,80mm – beige/green protect cap
Diameter of all is ½”

Colour of protection cap has to be double check before start of installation. Colour can change.The colour has no influence of the quality of the plastic. Each silo bolt is supplied with one galvanized silo washer and galvanized one silo nut. Nuts and washers are one size. The number of overlapping tank sheets and the attachment of angles or brackets determines the size and the quantity of the appropriate silo bolts.


The nut caps are placed on the outside of the tank. As an option, nut caps can be used.
They are put over the silo nuts, silo washers and the threads of the silo bolts.
The protecting caps are generally black as the sealant.
The Nut caps are only a visual item.



The used sealant is SIKA Sikaflex TS plus. This is a special elastic sealant, which is used for sealing tanks in segmented construction. The sealant is used for the sealing of the overlapping tank sheets in additional to the bolted connections. It seals against water and water-soluble chemicals. Black colour is usually used. For more details of the sealant please see the data paper of SIKA