These are two different services, with different tools, different time and different risk. Confusing them is the source of half the disagreements between client and provider after building work. Here is how to tell them apart, and why it changes the quote.
Routine maintenance
It deals with what time deposits on glazing: dust, pollution, rain marks, pollen, organic residue, handprints. This soiling sits on the glass. It dissolves, lifts and is squeegeed off.
The action is standardised, the duration is predictable, and so is the result.
Post-construction cleaning
It deals with what a building site left behind, and that is a completely different material:
- Plaster and sanding dust, which forms a very fine, highly adherent film and reactivates with every draught until the room is dusted;
- Paint splashes: acrylic, alkyd, lacquer;
- Cement, mortar, tile adhesive, laitance — the most aggressive, because they may have attacked the glass;
- Silicone and sealant overspilled then cured;
- Masking-tape residue and sun-aged adhesive;
- Labels and protective film left too long on the new glazing;
- Expanding-foam splashes or insulation products.
This material is stuck to the glass, not sitting on it. It requires contact work: specific products, dwell time, sometimes a carefully handled razor blade, and patience. The time per window can be several times that of a maintenance visit.
Three points of vigilance rarely explained
1. Cement and laitance may have etched the glass. A mortar splash left for several weeks under the rain attacks the surface chemically. Once the material is removed, a mark can remain — permanently. This is not a cleaning fault: the damage was already there, hidden under the deposit. It must be said beforehand.
2. Not all glazing tolerates the blade. Coated glass and some toughened or treated glazing have a surface coating a scraper can tear off. On this glazing the blade is out of the question, and certain splashes then become very hard to remove. The type of glazing must be identified before starting.
3. Post-construction cleaning done too late costs more. Fresh cement comes off. Six-month-old cement, far less. Fresh paint lifts; sun-baked paint does not. The longer you wait, the further the result recedes.
What this changes in the quote
| Routine maintenance | Post-construction | |
|---|---|---|
| Nature of the soiling | Deposited | Stuck or baked-on |
| Tooling | Standard | Specific, contact work |
| Time per window | Predictable | Highly variable |
| Result | Predictable | Clear improvement, no full guarantee |
| Frames and sills | Optional | Almost always necessary |
| Pricing basis | Surface and faces | Observed time and real condition |
Post-construction cleaning should never be priced at a maintenance rate, nor promised as a perfect result without having seen the real condition.
The order of operations, which matters more than you think
- Do not have the windows cleaned before the dirty work is finished. Sanding, painting and floor-laying care nothing for clean glass.
- Remove protective film in time. Film left for months in the sun leaves baked-on adhesive that is very hard to remove.
- Have the room dusted first. Cleaning glazing in a room still full of plaster dust means starting again the next day.
- Flag special glazing: coated glass, decorative sticker, solar film, old glass.
What we ask before pricing
- Close-up photos of the splashes, with a scale reference
- The nature of the work carried out and its date
- The type of glazing, if you know it
- The condition of the frames and sills, often far more affected than the glass
- Whether a protective film is still in place
On that basis we indicate what should come off, what is uncertain, and what will remain. If the uncertainty is too great, we suggest treating one test window first before committing to the rest.
FAQ
The building firm was supposed to clean. The result does not satisfy me. An end-of-site clean-up and a professional window clean do not aim at the same level. We price what remains, without commenting on the contract that binds you to the contractor.
Can you guarantee the paint will come off? No, not in advance. It depends on the type of paint, its age and the glazing. A test window lets you know before committing to the rest.
How long after the work should we intervene? As soon as possible after the dirty operations end. The residue hardens and bakes on over time.
Are frames included in a post-construction clean? They are almost always necessary: they catch most of the splashes. They appear explicitly in the quote.