Hi. I have been attempting to fix some villaboard sheets to the timber framing in my bathroom with self embedding screws but the screw heads keep finishing up sticking out from the wall slightly [ie. are not flush with the villaboard]. I've tried countersinking the villaboard for the screw heads before fixing in the screws but my countersink bit has become blunt very quickly, and there is a lot of screws to be used. Can anyone explain how to get screws flush in villaboard? Thanks.

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