Abstract: A door and window frame formed from two connected L-shaped members. One L-shaped member has a first arm and inner and outer second arms; both second arms are approximately perpendicular to and intersect the first arm. The second L-shaped member has single intersecting and perpendicular first and second arms. One of the second arms of the first L-shaped member, and the second arm of the second L-shaped member, are provided with teeth for holding the members in position to form the frame. One or both of the L-shaped members is provided with an internal groove which can support a deformable strip thicker than the depth of the groove.