A subframe configuration for a retrofit roof includes a subframe connected to the upper surface of a rib on an existing roof. The subframe is also connected to the valley/purlin of the existing roof. The connection can be a mechanical interference connection or one that is formed by a mechanical connector. The subframe of the disclosure includes a rib flange that extends from the bottom of the lip. The rib flange is disposed substantially parallel to the base of the subframe. When installed, a connector extends through the rib flange into a rib of the existing roof. Rib flange can be continuous or provided only at each or just some of the ribs.