Entry 16 · Windows & Glazing
Cleaning new windows, frames and glass properly
How to clean a newly fitted window and frame: surface order, what detergents contain, and mixtures such as bleach and ammonia that must never be combined.
A new window and frame are cleaned from the top down, starting with the glass and finishing with the frame, sill and floor, so that loosened dirt does not fall on surfaces already done. Use a pH-neutral detergent on the glass and a soft cloth or squeegee, and keep the frame dry at the seals. The same top-down logic applies to any building, and the wider method behind it is set out in Spanish-language guides on professional cleaning and hygiene, which cover surface mapping, cross-checking and chemical safety for teams.
01 In what order are surfaces cleaned in a building?
The working order in a building is decided before any cloth is wet. The usual sequence is: highest surfaces first, then middle, then low; dry work before wet work; and the least soiled area before the most soiled. In an office or shop this means ceiling vents and light fittings, then partitions and shelving, then desks and counters, then floors. Floors are always last because everything else drops onto them.
Within a single room, the same rule applies to a new window. Start at the top of the glass, work down in overlapping passes, then do the frame head, the jambs, the sill and finally the floor beneath. A squeegee used in an S-pattern, pulling from the top corner across and down, keeps dirty water from running back over clean glass. Change the water before it turns grey; a bucket of cloudy water simply redistributes the dirt.
Surface mapping is the step that makes this order reliable. Each surface is recorded with its material and its condition: glass, powder-coated aluminium, uPVC, timber, silicone seal, painted plaster, laminate, stainless steel. The map decides the cloth, the chemical and the contact time. A microfibre cloth used on a bathroom is not then used on a kitchen worktop. Colour-coded cloths, one colour per zone, are the simplest way to enforce that separation without relying on memory.
Cross-checking closes the job. A second person walks the area with the map and confirms each line, rather than the cleaner confirming their own work. For a newly fitted window this takes a minute: glass free of smears at an angle to the light, frame free of dust in the corners, sill dry, seal intact, floor clear of swarf and glass fragments.
02 What do detergents and disinfectants contain?
A detergent is built from a surfactant that lifts soil from the surface, a builder that softens the water, and often a solvent, dye, perfume and preservative. The surfactant is what does the work: one end of the molecule attaches to grease, the other to water, so the soil is carried away in the rinse. A disinfectant is a different product with a different job. It contains an active substance, commonly a quaternary ammonium compound, sodium hypochlorite, hydrogen peroxide or an alcohol, at a concentration that must be reached and held for a stated contact time.
pH tells you what a product is for. Alkaline detergents, roughly pH 9 to 12, cut grease and are used on kitchen canopies, oven interiors and industrial floors. Acidic products, roughly pH 1 to 5, dissolve limescale and mineral film, and are used on sanitary ware and some glass. Neutral products, around pH 6 to 8, are the safe default for glass, painted frames and most interior surfaces. A new window frame should be treated as neutral territory unless the installer's instructions say otherwise: strong alkali can dull a powder coating, and acid can attack the anodised layer or the seal.
Labels carry the legal information. Under the CLP Regulation, a hazardous product shows a signal word, hazard pictograms, hazard statements (the H-phrases) and precautionary statements (the P-phrases). The safety data sheet, which must be supplied for professional products, gives the pH, the active concentration, the contact time, the personal protective equipment and the first-aid measures. Gloves, eye protection and ventilation are not optional extras; they are the conditions under which the product is allowed to be used.
For a new window, the practical choice is a neutral detergent diluted to the maker's figure, applied with a cloth rather than sprayed onto the frame, and rinsed with clean water. Solvent-based cleaners, abrasive creams and scouring pads are avoided on glass coatings and on frame finishes.
03 Which mixtures must never be used together?
Bleach and ammonia must never be mixed. The reaction releases chloramine gases, which irritate the eyes, throat and lungs and can cause serious breathing difficulty in a confined room. Bleach and acid must never be mixed either: hydrochloric acid plus sodium hypochlorite releases chlorine gas. Both combinations have caused hospital admissions, and both are avoidable because the two products are never needed in the same bucket.
Other combinations to keep apart: bleach with vinegar, bleach with hydrogen peroxide, and bleach with any product whose label lists ammonium compounds. A disinfectant and a detergent should not be poured together in the hope of saving a step, because the two can neutralise each other and leave a surface that is neither clean nor disinfected. If a surface needs both, clean first, rinse, then disinfect, and allow the stated contact time.
Storage matters as much as mixing. Products are kept in their original labelled containers, never decanted into a drinks bottle, and stored by compatibility: oxidisers away from flammables, acids away from alkalis, and everything away from food. Ventilation is the control that limits exposure when a product is used at all, and a window being cleaned is often the best source of it.
04 How should a newly fitted window and frame be cleaned?
Wait for the installer's sealant and any decorative finish to cure before wetting the frame, and follow the maker's written instructions if they differ from general practice. Remove protective film and any adhesive residue first, using the method the manufacturer specifies. Then work top-down: glass, frame head, jambs, sill, floor.
Use two cloths, one for washing and one for drying, and a squeegee for the glass. Keep water out of drainage slots and away from the seal between frame and wall. On uPVC, a neutral detergent and a soft cloth are sufficient; on timber, wring the cloth so it is barely damp and dry the surface afterwards; on aluminium, avoid abrasive pads that break the coating. Glass with a factory coating should be cleaned with a neutral product and a soft cloth, never a scraper.
Finish by checking the frame at an angle to the light and running a finger along the sill. Any grit left there will scratch the glass on the next clean.
05 What records should be kept?
A cleaning job is only complete when it is written down. The record should name the area, the date, the product with its dilution, the contact time where a disinfectant was used, and the person who carried it out. In food-handling premises this record forms part of the HACCP traceability system, and in commercial contracts the cleaning specification and its frequency are usually written into the agreement.
Keep the safety data sheets for every product on site, and keep them current: a sheet for a discontinued product is of no use in an incident. Staff who handle chemicals should be able to find the sheet, read the pictograms and state what to do if the product reaches the eyes or skin. For a household, the equivalent is a single folder with the window installer's guarantee, the product instructions and the date of the first clean.
06 Frequently asked points
A new window does not need a stronger product than an old one; it needs a gentler one, because the frame finish and the glass coating are new. Microfibre and clean water do most of the work. Disinfectant is for surfaces where hygiene is the objective, not for glass. And no product should ever be mixed with another outside the maker's instructions, whatever the time saved appears to be.