The strength of a raft of Permavoid units is not only determined by the strength of the units but depends on the strength of the joints in between the units too. The Polypropene PermaTies are designed to be slightly conical so they pull the individual units tightly together to form a rigid raft. For the Permavoid 150 two ties per joint over the full depth are used (one inserted from each side), where for the Permavoid 85 and 85S one PermaTie per joint suffices. The PermaTies are white, so during installation one can easily spot where one is missing.

Specs & downloads

Everything you need to know.

Technical data

47 x 37 x 74 mm (l x w x h, approx.)
Polypropene (CoPo)
approx. 35 g
Material description
Frost resistant, hydrofoob, inert, acid and hydrocarbon resistant, impervious to bacterial and fungal growth
Coefficient of Lineair Thermal Expansion
0,0004 - 0,0008 m/m K
> 50 years


Got a good idea? A new product or want to cooperate? We aspire to do what others cannot. Join us to build the future of  technology solutions.

We have built a reputation

Find your local distributor nearby.

Permavoid source control ensures that no precious water goes to waste by catching, storing and reusing stormwater for irrigation, evaporation and infiltration. Find your local Permavoid distributor here to learn more about the technology and become part of the international movement.