Casement Window Fittings That Cope Better With Spring Movement

Every spring it happens. The weather turns, temperatures start climbing, and suddenly your casement windows are a daily frustration. The handle will not pull flush. The lock will not quite engage. The window drags on the frame when you try to open it. Sound familiar?

This is one of the most common issues we hear about at SDS London around this time of year, and the good news is that it is almost always fixable. In most cases the culprit is not a broken window. It is fittings that were not designed, or have not been maintained, to handle the natural movement that happens every spring.

In this post we will explain exactly why spring movement causes casement windows to play up, which fittings are most likely to be the problem, and what to replace them with. We have linked to the relevant products in our online store throughout, so if you already know what you need you can get straight to it.

1. Casement Stays

The casement stay is the arm that holds your window open, and it takes more abuse from spring movement than almost any other component. If yours is stiff, bent, or no longer sitting flush in its pins, it is probably overdue a replacement.

For period properties and timber casements, we recommend the Monkey Tail Casement Window Stay. Hand finished in solid brass in Birmingham, it has a classic design that looks the part and holds up well over time. It is the kind of fitting that will still be working correctly in ten years, which is exactly what you want from a stay on a well-used casement.

For modern uPVC or aluminium casements, a functional stay in a matching finish is usually the right call. Our range covers finishes from polished chrome to satin black, so finding a match is straightforward.

2. Window Hinges

If your casement sash has dropped, or if there is a visible gap at one corner when the window is closed, the hinges are the most likely cause. Worn or underrated hinges sag progressively under the weight of the sash, and spring movement accelerates the process.

For top-hung casements or windows where child safety is a priority, the Friction Hinge Top Hung 509mm is a solid choice. It restricts initial opening to 100mm in compliance with BS 8213 Part 1, supports sash weights up to 24kg, and is made from stainless steel. That last point matters more than people often realise: stainless steel handles seasonal humidity and temperature cycling without corroding, which means the hinge keeps performing year after year rather than stiffening up each spring.

3. Espagnolette Systems

If your casement handle turns but the window will not lock fully, or you have to lift the sash to get the lock to catch, the espagnolette system is almost certainly out of alignment due to spring movement.

The Mortice Espagnolette 1320mm works for both inward and outward opening casements, side hung or top hung. It has a 12mm hook bolt throw for positive engagement even when the sash has moved slightly due to seasonal expansion, and the length can be shortened to suit your specific window height. If your existing espagnolette can no longer be adjusted to compensate for movement, this is a reliable replacement worth considering.

4. Casement Window Locks

For windows showing signs of wear, or where security is a concern, adding a dedicated casement window lock alongside your existing fastener is a low-cost upgrade that makes a real difference. Our locks are available in brass and steel with finishes to match your existing furniture, all include a removable key, and they work on both timber and metal casement windows. They can also restrict how far the window opens, which is a useful feature for upper-storey windows.

• Lubricate everything. A light machine oil or dry lubricant on hinges, stay tracks, and espagnolette mechanisms can resolve stiffness caused by seasonal dryness and dust build-up. Avoid petroleum-based products on uPVC frames.

• Adjust your hinges. Many modern hinges have adjustment screws (usually a hex key) that let you reposition the sash without removing anything. A small vertical or lateral adjustment often restores locking engagement.

• Check your fixings. Seasonal thermal cycling means screws loosen over time. Go around every piece of hardware and tighten anything that has backed out.

• Clean the locking points. Grime build-up on espagnolette cams and strikers can prevent full engagement. A wipe-down is sometimes all that is needed.

• Genuine range and real choice. From traditional brass stays to stainless steel friction hinges, all in one place, across a wide range of finishes.

• Fast UK delivery. Most stock lines were dispatched the same day on orders placed before midday.

• Trade accounts available. Exclusive pricing and benefits for contractors, property managers and specifiers.

• Expert advice on hand. Not sure which product is right for your window? Get in touch and our team will point you in the right direction.