Router grooves on door leaf allowed?

[Guest Calire]

Good afternoon, I am interested in purchasing ply flush fire doors but was wondering if shallow router groves can be added as a decorative feature. Is they a maximum depth ?

I would appreciate any help on this matter

Kind regards
Claire

[Tom Sutton]

If you carry out any modifications to a certificate fire door you stand a chance of invalidating the certificate and there is no way of knowing if the fire resistance has been compromised.