When to Call a Professional for Window Repairs

Most window faults announce themselves quietly. A handle that needs a little more effort, a draught you notice only on windy days, a faint bloom of condensation trapped between two panes of glass. Some of these are simple fixes that a competent DIYer can handle with a screwdriver and half an hour. Others are symptoms of something that will cost far more to put right if you ignore it, or if you attack it with the wrong tools and make it worse.

Here is a practical guide to the point at which it is worth paying for an experienced installer rather than reaching for the toolbox yourself.

Broken or Dropping Hinges

uPVC windows are heavy. A typical double-glazed casement can weigh 20–30kg, and all of that load is carried by two or three hinges screwed into a reinforcing chamber inside the frame. When a hinge starts to fail, the first sign is usually a sash that scrapes the sill or catches on the frame as you close it. You might also notice the handle needing a firm push before it will turn.

Adjustment is a different job from replacement. Friction stays on top-hung and side-hung windows can often be nudged back into alignment with an Allen key, and that is well within reach of most homeowners. But the moment you see any of the following, stop and call someone in:

• Visible cracking or distortion in the hinge itself, or screws that will no longer bite because the fixing holes have worn oval
• A sash that has dropped so far that the locking points no longer line up with the keeps
• Any sign of movement in the frame around the hinge, which can point to a deeper problem with the fixing or the wall

Fitting a new hinge is not simply a case of swapping like for like. Hinges are matched to the profile system, the sash weight and the opening direction, and getting it wrong can leave the sash hanging badly or, worse, unsupported.

Misted Double Glazing and Failed Seals

Condensation on the inside of the glass is normal in a kitchen or bathroom. Condensation between the panes is not. It means the hermetic seal around the edge of the sealed unit has failed, letting in moisture that the desiccant in the spacer bar can no longer absorb.

There is no repair for a failed unit. Anyone offering to drill, drain or inject a misted unit is selling a temporary cosmetic fix that will cloud over again within a season. The only proper remedy is a replacement sealed unit, made to the correct dimensions and specification — usually 4mm glass, a 16mm cavity and 4mm glass, with a warm-edge spacer and argon fill if you want to keep the thermal performance of the original window.

What an experienced installer brings to this job is judgement about whether a replacement unit is the sensible answer at all. If a window is 20 years old and the frame is sound, a new unit is excellent value. If the same window has misted twice in five years, or the frame has started to bow, the honest advice may be that you are throwing money at a window that has reached the end of its life.

Structural Movement, Cracks and Bowed Frames

uPVC is rigid, but it is not infinitely so. A frame that has visibly bowed, or where the glass has cracked without impact, is telling you that something is moving. Common causes include a sill that was not packed and supported properly, a lintel that has settled, or thermal movement in a long run of glazing that was installed without the necessary expansion gaps and coupling mullions.

This is the point at which DIY repairs become actively risky. Tightening screws into a moving frame will not stop the movement, and it can crack the profile. An experienced fitter will check whether the frame is plumb, whether the glass is correctly toe-and-heeled in the rebate, and whether the opening itself has changed shape. Sometimes the answer is a straightforward re-fix with better packers. Sometimes it is a conversation about replacement, and you want that conversation with someone who has seen it before.

Doors That Drop, Drag or Refuse to Lock

Composite and uPVC doors carry far more weight than a window, and they are used dozens of times a day. A door that has dropped slightly can often be lifted back on its adjustable hinges in ten minutes. But when the multipoint lock no longer engages smoothly, the problem is rarely the lock itself.

Multipoint mechanisms have hooks, rollers and shoot bolts that must all meet their keeps at the same time. If the door leaf has twisted, if the frame has moved, or if the gearbox has worn, forcing the handle will eventually strip the mechanism — an expensive mistake. Feel for a handle that has become stiff or gritty, look for daylight around the edge of the door when it is closed, and check whether the door has to be lifted before the key will turn. Any of these warrants a professional assessment, and often a simple adjustment rather than a new lock.

What a Professional Assessment Actually Involves

A good installer will spend the first ten minutes looking rather than quoting. Expect them to check the frame for plumb and square, examine the gaskets and drainage slots, test the locking points, and ask how long the fault has been present and whether it appeared suddenly.

Ask for a written explanation of what has failed and why, and what the options are. Repair-first advice is a good sign. So is a clear statement of what is guaranteed and for how long — sealed units are typically covered for five to ten years, hardware for two to five. If you are having glass or a full window replaced, check that the work will be notified under a competent person scheme or covered by a building control application, so you have the paperwork if you ever sell the house.

Some jobs are satisfying to do yourself. Knowing which ones to hand over is what keeps the rest of your windows watertight, quiet and warm for years to come.