Screwfix PVC-U Window Installation Guide

Quick guide from the manual

This guide covers the installation, glazing, and maintenance of PVC-U windows. Before starting, ensure you have inspected the window for damage within 48 hours of delivery. Always remove protective corner blocks before installation and maintain a 5mm expansion gap around the frame.

Delivery contents

• PVC-U window: Arrives with corner blocks attached for protection.
• Handle: Pre-fitted with protective mesh.
• Trickle vents: Taped to the window.
• Glazing packers, cill, and end caps: Taped to the window cill.

Fitting the new frame

Remove the old frame and clear all debris. If fitting a cill, cut it to size with a fine-toothed saw to fit tightly against the inside edge. Apply sealant along the cill upstand and frame platform, then screw the cill to the bottom frame section.

If the window is too small for the aperture, use frame extenders (15, 20, or 35mm). Offer the frame into the opening, use a spirit level to ensure it is level, vertical, and not twisted. Use packers underneath to centralize and maintain a 5mm expansion gap.

Affixing the new frame

1. Remove packaging and screw the cill to the bottom of the frame.
2. Seal the ends of the cill and frame to prevent moisture ingress.
3. Position the frame in the aperture and use packers to level it.
4. Drill fixing holes 150mm from the top and bottom corners, and 600mm apart (minimum 2 fixings per side).
5. Fix the frame to the wall using packers to avoid distortion; do not overtighten.
6. Seal top and bottom fixings with silicone.
7. Insulate the gap between the frame and aperture with expanding foam or tape.

Glazing

To glaze the window, remove the glazing beads using a sharp chisel or scraper. Place glass packers 100mm from each corner (use intermediate packers for units wider than 1200mm). Place the double-glazed unit into the frame and refit the beads using a rubber mallet.

Toeing and heeling: This is essential to prevent the sash from dropping. Brace the glass diagonally by inserting plastic packers in the gap between the glass and the frame. On the hinge side, place packers at the bottom corner; on the lock side, place them at the top (opposite) corner.

Adjustments

• Window hinges: Generally require no adjustment. If needed, adjust the friction stay tension using the brass screw in the black plastic pad.
• Locking mushroom cams: Use an Allen key in the center of the cams to adjust closing pressure if the vent is difficult to close.

Maintenance and care

• Clean PVC-U frames twice a year with warm soapy water.
• Clean glass with a clear liquid spray cleaner.
• Do not use abrasive cleaners, bleach, solvents, or adhesives.
• Lubricate moving parts and locking mechanisms with light oil annually.
• Keep drainage channels clear of blockages.

Warranty

Your new product carries a manufacturer’s warranty of 15 years.