Window Installers near you

Settle the notification route in writing before the survey, not after the old frames are in a skip. Under a competent person scheme the installer registers the job themselves and a certificate follows; outside one, an application goes to a building control body and an inspection is arranged and paid for. FENSA is blunt about where the risk lands when nobody establishes this at the outset: if your installer does not mention that you are responsible and does not offer a FENSA certificate or other building regulations compliance certificate, you will need to pay for an inspection by building control.

Ask for the scheme registration number and check it against the scheme's own register rather than accepting a logo on a van or a quotation. Membership is not a one-off badge — CERTASS describes itself as a UKAS accredited certification body and a government authorised certification body since 2006, whose members can self-certify installations as an alternative to Building Control, and FENSA says each of its approved installers, from large national brands to small local companies, is assessed regularly to ensure compliance with building regulations is continually maintained.

Scotland and Northern Ireland are separate systems and the scheme names do not travel. Scotland works under the Building (Scotland) Act 2003, where local authority verifiers are responsible for granting permission for work to be done, through a building warrant, and for a completed building to be occupied, through a completion certificate, against the Scottish technical handbooks. Northern Ireland's building regulations are made by the Department of Finance and administered by 11 district councils, with guidance in technical booklets. Ask the local authority what your job needs before you assume an England and Wales answer applies to your postcode.

Dropping a new unit into an opening that already exists is a different project from cutting a hole in a wall, and the two are quoted, approved and programmed differently. A replacement is notifiable work that a scheme member can self-certify in an afternoon. A new opening needs the wall above it supported, a lintel sized for what it carries, and the structural thinking that Approved Document A governs, so it usually involves a structural engineer or a building control application in its own right.

Planning permission usually sits outside all of this. The Planning Portal's position is that you do not normally need to apply for planning permission for the insertion of new windows and doors that are of a similar appearance to those used in the construction of the house, though a new bay window is treated as an extension and may require permission. Two exceptions catch people out: in a designated area such as a conservation area, national park or area of outstanding natural beauty there may be additional restrictions, and a council can make an Article 4 direction withdrawing permitted development rights so that an application becomes necessary.

There is also a rule aimed squarely at overlooking. Where new windows are in an upper-floor side elevation, the Planning Portal says they must be obscure-glazed and either non-opening or more than 1.7 metres above the floor level of the room they serve. An installer who has never mentioned it on a first-floor side wall has not thought the job through.

Most complaints about new windows are complaints about fitting rather than about the units themselves. Draughts at the edge of a closed casement, a frame that has been packed out unevenly, sealant smeared over a gap that should have been closed properly, and drainage slots along the bottom of the outer frame left blocked or never formed all point at workmanship. So does a sash that binds in one corner or a handle that needs lifting before it will engage.

Condensation is the fault most often misdiagnosed. Government guidance describes condensation damp as moisture generated inside the home cooling and condensing onto colder parts of the building, naming window frames among them, so water on the room side of new glass is usually a ventilation and heating question rather than a defective unit. The same guidance asks directly whether windows have trickle vents and whether they are kept open and free from blockages. Misting sealed between the panes is the opposite case and is a genuine product failure.

Raise defects in writing while the installation is fresh and while the guarantee and the scheme complaints route are both available to you. Photograph what you can see, note the dates, and keep the correspondence with the certificate.

FENSA describes its certificate as a declaration by the installation company to the homeowner that the windows and doors they have replaced comply with Building Regulations, use energy efficient products and are registered with the local council, and says it verifies that the warranty is insured and is essential when selling the property. That last point is the one with money attached, and GOV.UK puts the general case plainly: without approval you will not have the certificates of compliance you may need when you want to sell your home.

A guarantee from the installing company is only worth as much as the company behind it, which is why the insurance matters. FENSA notes that where an installation was completed after 2014 you may have received an insurance backed guarantee policy, covering the installer's written guarantee in the event that they cease to trade. Ask whether one is being provided, who underwrites it, and how a claim would be made if the firm no longer existed.

File everything together the day it arrives: the certificate, the guarantee and any insurance policy, the quotation and specification, and any structural advice for a new opening. A buyer's solicitor will ask for the certificate years from now, and reconstructing the paperwork mid-sale is far harder than keeping it.