The primary functions of a uPVC casement door keep are:

1. Security: It provides the secure anchor points for the various locking mechanisms (like mushroom cams, roller cams, deadbolts, and hooks) on the door sash. When the handle is lifted or the key is turned, these bolts extend into the keeps, securely locking the door in place and preventing forced entry.

2. Sealing and Weatherproofing: By ensuring a tight and consistent engagement between the door sash and the frame, keeps contribute to the door’s overall seal. This helps prevent drafts, water ingress, and noise transmission, enhancing the door’s thermal and acoustic insulation properties.

3. Smooth Operation: Properly aligned and functioning keeps allow the door to close and lock smoothly without excessive force or friction.

4. Alignment: Keeps help maintain the correct alignment of the door sash within the frame, which is essential for both security and efficient operation.

Types of uPVC Casement Door Keeps:

Keeps vary depending on the type of locking mechanism used in the door and the profile of the uPVC frame. Common types include:

• Mushroom Keeps: Designed to engage with “mushroom cams” on the door lock, offering a high level of security by creating a strong interlocking system.

• Roller Cam Keeps: Used with “roller cams” (or “roller bolts”), these provide a smoother closing action and good compression for sealing.

• Hook Bolt Keeps: These are designed to receive hook-shaped bolts from the locking mechanism, offering strong anti-jemmy (anti-prying) protection.

• Deadbolt Keeps/Latch Keeps: These are for the main latch and deadbolt of the lock, which are usually operated by the handle and key.

• Universal Keeps: Some keeps are designed to be more versatile and fit a wider range of uPVC profiles and locking systems.

When replacing or troubleshooting a uPVC casement door, it’s often the keeps (along with the hinges and the main locking mechanism) that need inspection to ensure proper function and security.