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Advice: Using zinc-plated anchor screws in the facade

It is no secret, but many contractors do not know it: Anchor screws made of zinc-plated steel may also be used outdoors and offer an economic alternative to stainless steel screws. The European Technical Approvals/Assessments ETA-10/0035, ETA-12/0502 and ETA-15/0027 which are relevant for EJOT facade anchors say:

"The special screw made of galvanic zinc-plated steel may also be used outside, after careful installation and if the area of the screw head is protected against moisture and driving rain in such a way that no moisture can enter the anchor shaft. This requires facade cladding or rear-ventilated facade fixed in front of the screw head and the screw head has to be coated with a soft-plastic, permanently elastic, bitumen oil combination coat (e.g. car underbody coating or cavity protection)."


Brush or spray can? 

It is not the process which is decisive for the functionality of this coating, but the quality of application. At the end of the day, a complete waterproofing of the screw head must be guaranteed. For this purpose, a soft-plastic bituminous paint can be done. In practice, a spray can with car underbody corrosion protection is used. A few short sprays are enough to prevent moisture penetration. A work step which takes only a few seconds.
One or two short sprays are enough to protect the screw head from moisture and driving rain.