Common Installation Mistakes
Written by Cornwall Composite DoorsReviewed by Cornwall Composite Doors installersLast updated July 20265 minute read
Short answer
The most common composite door installation mistakes are fitting an out-of-square frame, inadequate sealing around the perimeter, poorly adjusted hinges or locking mechanisms, and using the wrong fixings for the wall type. These lead to draughts, sticking doors, or water ingress over time.
A composite door itself is a durable, well-engineered product, so when problems arise they're usually down to how it was installed rather than the door. Knowing the common pitfalls helps you judge the quality of a quote or a completed job.
Frame not fitted square or level
If the frame isn't properly squared during fitting, the door can bind against the frame, fail to latch cleanly, or sag over time under its own weight. This is checked with a spirit level and diagonal measurements, not by eye.
Inadequate sealing around the frame
Gaps left between the frame and the wall, or foam and sealant applied too thinly, allow draughts and water to get in over time. This is a common cause of damp patches or cold spots appearing near a door months after installation.
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Wrong fixings for the wall type
Granite, stone, brick, and timber sub-frames all need different fixing approaches to hold the frame securely. Using generic fixings not suited to the wall material can lead to a loose frame that moves or creaks over time.
Poorly adjusted hinges and locking mechanism
A multi-point lock and hinges need fine adjustment after fitting to engage smoothly. Skipping this step results in a door that's stiff to lock, doesn't latch consistently, or requires you to lift the handle awkwardly to operate it.
Rushed threshold fitting
The threshold needs to sit correctly against the floor to seal out draughts and water without catching underfoot. A poorly fitted threshold is one of the most common sources of complaints after installation, particularly in exposed, wind-driven Cornish weather.
Frequently asked questions
How can I tell if my door was installed correctly?
Check the door closes and locks smoothly without lifting or forcing the handle, that there are no visible gaps around the frame, and that you can't feel a draught around the edges on a windy day.
Can a poorly fitted door be corrected later?
In many cases yes, adjustments to hinges, locks, and even re-sealing can resolve minor issues. Serious problems like an out-of-square frame may need the frame refitted properly, which is more involved and costly.
Does a guarantee cover installation faults?
A proper installer's guarantee should cover workmanship as well as the product itself. Our 10-year written guarantee covers both, so installation faults are put right without additional cost to you.
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More installation advice
- What Happens During Composite Door Installation?From dust sheets to final checks, here's what a professional composite door fitting actually involves.
- Measuring for a Composite DoorAccurate measuring is what separates a snug, weathertight door from one that draughts or sticks.
- DIY vs Professional InstallationComposite doors are heavy, precise products — here's why fitting one yourself is rarely a good idea.
