Product Maintenance Tips & Instructions  


          Perfect Crystal Windows' doors, windows, roof lights accessories are high-quality products. In order to ensure their lasting serviceability and durability, as well as to prevent personal and material damage, their professional service and maintenance is essential. In this document you will find advice accordingly. Disregarding this information could lead to exclusion from warranty and product liability claims. Functional
impairments or wear and tear of parts, which usually occur within the limits of normal and proper use, are not covered by warranty obligations. Excluded is also any damage which is the result of improper handling, unintended use of the product and attempts of repair by unqualified persons



          Perfect Crystal Windows' products are low-maintenance, easy to clean and to care for. Regular maintenance conserves value and extends the life span of our products. If you adhere to the following cleaning, care and maintenance tips, you will be able to enjoy your Perfect Crystal Windows products for a long time. In order to retain an immaculate surface, smooth-running hardware and well closing gaskets, please take note of the following care tips.

          Do not use cleaning products of unknown composition. If you are uncertain about the effects of a cleaning agent, test it on an inconspicuous, concealed part. Please be aware that cleaning agents which cause surprising cleaning results without any special effort might often lead to long term damages. Outside surfaces are not only exposed to weather, but also to the increased effects of smoke, industrial fumes and aggressive fling dust. Deposits of these substances combined with rain or condensation can impair surfaces and alter the decorative appearance. We recommend regular cleaning of the outside surfaces, depending on the degree of staining, in order to prevent long term settling of deposits. The sooner stains are removed from the surface, the easier their cleaning will be.


          All hardware parts are to be checked regularly for tight fitting and for wear and tear. If necessary, fixing screws need to be tightened or faulty parts need to be replaced by authorised personnel. Furthermore, all gliding parts and movable hardware parts have to be greased once per year (acid free grease or oil). Hardware should only come in contact with those care and cleaning agents that do not impede the corrosion protection of the hardware parts.

Cleaning tips: Glass surfaces

          Dirty glass surfaces can be cleaned wet with water, sponge, cloth etc. Common glass cleaners without scouring agents may be added to the water. Persistent stains such as paints or tar droplets should be removed with methylated spirits, acetone or petroleum ether. The glass surface should then be cleaned wet again. Metallic items (e.g. razor blades, steel wool ...) must not be used!

          Do not use alkaline cleaning lye, acids or cleaning agents containing fluoride to clean the glass surface. Protect the glass surface with suitable cover foils from plaster splatters, cement, untreated concrete surfaces, fire cement boards, flying sparks or welding beads from angle grinders, acidic facade stone cleaners.


          All gasket profiles have to be cleaned and greased at least once per year to retain functionality. Ensure a suitable care product is used for the gaskets. The care product for gaskets must retain the pliability of the gasket and prevent it from becoming brittle prematurely. Please ensure the gasket profiles are not damaged and do not come into contact with solvents. Generally, gasket should only be cleaned with water and possibly a little bit of dishwashing liquid.

Permitted cleaning agents:
• Alkaline cleaning agents (soapy solutions)
• Mixtures of water and alcohol
However, concentration, exposure time and ambient temperature play an important role. It could damage the material if the concentration of the cleaner is too high.

Prohibited cleaning agents:

• Cleaners containing chlorine or cleaners with peroxides can damage the material over a longer period of time or it could lead to discolouration.
• Oils, greases, oil and grease containing substances and petrol can lead to a cracked and unsightly appearance.

          Use only appropriate care products that are available for cleaning uPVC surfaces. Especially avoid aggressive and dissolving cleaning agents and avoid direct sunlight during cleaning on the areas which need to be cleaned. 



Timber products Internal surfaces

          We recommend using mild cleaning products, such as diluted washing-up liquid or soapy water, to clean inside timber surfaces. As timber surfaces on the inside are not exposed to weather (wear through rain and sunlight), coating is not necessary. Avoid scouring, acidic and solvent cleaning products. Only use soft cleaning cloths to avoid scratching the paint surface. Window cleaners contain small amounts of alcohol and ammonium chloride. These products are well-suited to clean glass panes, as well as timber frame profiles. Dry the timber profile thoroughly after cleaning with a dry, soft cloth, as alcohol applied to the paint surface for too long, can dissolve it.

Timber products External surfaces

          Depending on location, it is recommended that any external timber is painted every 2 – 3 years. In particularly exposed areas constant monitoring of the external surface is recommended to ensure no deterioration. In order to retain the attractive external appearance of your timber products during and after the construction period, the interior rooms must be well ventilated.

          Be aware of water vapour during the building phase. During the drying phase of new buildings, a large amount of water vapour is set free from the inside plaster and cement based floor. The connection between the quantity of water produced, and the time interval taken for the water vapour to diffuse through walls and windows will vary. Without sufficient ventilation, the water vapour arising from the drying of the concrete floor and interior plaster will not escape from a new building in the required time.

          As the consequence of the lack of ventilation, so-called ‘winter building damages’ occur. Water vapour gains access at weak points in the timber (for example, glazing rebates). This condenses and the moisture content of the timber increases to in excess of 30%, resulting in difficulties in opening the windows and damage to the glue bond and/or the danger of infestation by wood destroying fungi increases. In extreme cases bubbles, which may be filled with water, will form on the exterior faces.

During the plastering and the following drying period, damages can be avoided if sufficient ventilation (i.e. opened window) is used.


1. In a warm interior building, large amounts of water vapour is released deriving from the freshly applied masonry, plaster and concrete floors.

2. The arising water vapour condenses on the cool parts of the external wall. On wooden windows and doors, the water vapour follows the heat flow through the timber and condenses between the wood and the protective coating.

3. Due to extreme humidity, an increased water vapour pressure against the protective coating arises whereby the wood fibre saturation point is very high. As a consequence, blistering as well as wood damages can occur.

4. High room humidity can in addition lead to health and construction damages.

5. Natural timber always tends to adapt to its surrounding humidity. This characteristic remains the same throughout the entire life cycle, from the living tree to the processed timber element. Protect your windows especially during the construction period from excess construction humidity. This applies especially to winter construction sites, where large amounts of water occur.

6. Due to the low temperatures and the reduced ventilation during the winter months, the wooden windows are particularly endangered due to plastering and screed works in closed buildings.

7. Only suitable adhesive tapes may be used for the masking of the coating. Please note Perfect Crystal Windows cannot recommend a product as each application situation can be different. 

8. A short airing period is not sufficient to reduce the high humidity. The regular airing, especially during the building operation must be repeated regularly. It is recommended to provide an on-going draft.

9. In heated rooms the hazard of humidity damages is smaller. There is less humidity in heated rooms, as in unheated rooms.

10. Supplementary, the windows should be left top/side hung open during construction work.

11. Too high humidity over a longer time period can lead to swelling of timber profiles and cause severe damage on corner connections and surfaces.


As a general guideline, you can simply compare your windows with the ones depicted below and assess whether the construction humidity and therefore the moisture in the timber is alright. 

Flush Timber

Flush top and bottom corner connections guarantee
that the moisture in the timber is in the permitted standard range.


Blown timber due to excess moisture

Horizontal timber elements are not flush in the corner connections
and therefore project. This is a clear indication
that the timber elements have swollen up due to excess moisture.
Ensure sufficient ventilation and dry out the timber elements.




Aluminium powder coated or anodised products

          Anodising and powder coating are considered refinements of exterior aluminium surfaces which are especially durable and decorative. In order to retain the decorative appearance of these construction parts for decades and to reduce corrosion impact, the surfaces need to be looked after at least twice per year with adequate cleaning and surface conservation products. Depending on the degree of staining (strong stains) care and cleaning intervals should be shortened accordingly.

          Do not clean surfaces in direct sunlight. The surface temperature must not exceed 25° C. Use suitable cloths for cleaning, which do not scratch the surface. Refrain from tough scrubbing. Pre-cleaning before applying special cleaning or conserving products, existing stains should be removed in a pre-cleaning process. Use only clean water for this, possibly with small amounts of neutral cleaning agents (only pH neutral cleaning agents with a pH value between 5 and 8) e.g. washing-up liquid in normal concentration. These cleaning products should not be warmer than 25° C. Do not use steam cleaners.

          General cleaning is necessary if persistent stains are present or when elements have not been cleaned for a long time. Special abrasive cleaning agents should be used for these. Eloxal Clean for anodised aluminium surfaces. Powder Clean for powder coated aluminium surfaces. These general cleaning products should only be used after a successful pre-cleaning process. After the general cleaning process, treatment with conservation agents is necessary.


          Conservation agents are used to apply a film with temporary stain and water repellent effect to anodised or coated aluminium parts, which also improves the decorative appearance of the surface. The conservation has to be renewed from time to time. Eloxal Polish Cleaner for anodised aluminium surfaces, Powder Polish Cleaner for powder coated aluminium surfaces. Conservation agents should only be applied after a successful pre-cleaning.

Cleaning for anodised surfaces

          When cleaning very dirty anodised surfaces, do not use scratching or scouring products. Persistent stains such as tar, lacquer or similar compounds can also be removed with solvents, e.g. benzine or cellulose thinner (only for local application and with corresponding subsequent treatment). Observe the respective safety and handling instructions for each product. Gaskets or painted surfaces must not come in contact with these products.

          A general cleaning agent can be used which is an acid and alkaline free intensive cleaner for slightly to strongly stained anodised aluminium surfaces. It contains small abrasive particles, adapted to the anodised surface, grease solvents and a combination of other cleaning additives.

          Apply to a damp cloth, fleece or sponge and rub with evenly applied pressure on to the anodised surface. Only treat one section at a time. Rinse the cloth, fleece or sponge in between. The time spent and the pressure applied depends on the intensity of the staining. After the cleaning process rinse off the anodised surface thoroughly with clean water, until all residue is removed.

Cleaning for powder coated surfaces

          Solvent containing acidic and alkaline cleaning agents affect the surface of powder coatings and must not be used; the same applies to scratching or scouring cleaning agents. In order to remove persistent, greasy, smeary stains we recommend cleaning benzine or isopropyl alcohol (IPA). Leave it on the surface only for a short time and rinse off with clean water. Another general cleaning agent is an intensive cleaning agent for chalky and strongly stained powder coated aluminium surfaces. These contain small abrasive particles, adapted to the powder coated surface, grease solvents and a combination of other cleaning additives. This product can be purchased as a paste. Ensure you check the suitability from your supplier. After the cleaning process rinse off the powder coated surface thoroughly with clean water, until all residue is removed. For decorative reasons stained powder coated aluminium surfaces should be cleaned several times each year.

Cleaning instructions for stainless steel

          Stainless steel is used in the building industry primarily where aesthetics and hygiene are the main focus. As it cannot be avoided that a rust film or flash rust may deposit on the surface, this often leads to the erroneous assumption that stainless steel has rusted. We recommend treating surfaces with visible stains or corrosion using standard stainless steel cleaners. These can be obtained in respective specialist shops.


Find out more about maintenance of bi-folding doors.

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