Treating Wooden Windows

General Information
Windows are subject to severe stress from all sides: from frost, sunlight, and rain outside and from steam, condensation and mechanical stress when opening and closing inside.
KREIDEZEIT Wood Lazures and particularly the opaque Stand Oil Paints are ideally suited to with-stand all of these demands.
They combine firm weather resistance, durability and colour retention. Damage from waterlogging is reliably avoided thanks to optimal vapour permeability.
KREIDEZEIT Wood Lazure and Stand Oil Paint do not crack, tear or peel, but remain permanently elastic and gradually weather on the surface. They are easy to clean and paint over when decorating, even after several years.

Wood Protection by design
Keeping wood dry and preventing any long-term exposure to moisture significantly prolongs the life of a coat of paint. However, protecting your wood starts even before applying any products: it already starts in the construction phase. When you are planning your project, you should consider preven-tative measures such as separating the wood from the ground, using large roof overhangs, bevelling horizontal surfaces, creating drip edges, protecting the end grains and providing a ventilation cavity behind cladding.

What to consider when choosing a Colour
Apart from your own personal choice of colour, you also need to bear in mind how often you need to care for and reapply the coat.
Outdoor coats must be tinted with a colour pigment to provide UV protection. The pigments protect the wood from going grey and the paint coats from premature weathering. The more pigment you use, the better the UV protection and the longer the paint will last. In a nutshell, paint coats treated with opaque stand oil colours last the longest. In tinted varnishes, dark pigments (red, brown and black) provide better UV protection and do not need to be reapplied as often compared to lighter ones (pine/spruce shades). This is regardless of whether synthetic resin varnishes or natural dyes are used.
However, wood with precise dimensions (such as wood windows) should preferably be painted with bright colours. Dark tones may overheat during exposure to sunlight, which can cause the wood to warp.
We advise against using varnished white and light grey tones with Titanium White because of the insufficient UV protection offered.

Window manufacturers usually only uphold the guarantee on their windows if you use the painting system recommended by the manufacturer on the windows. If you use a different type of paint, this could void the warranty.

For wooden windows finished with Kreidezeit products that come with a warranty and are available from distributors nationwide, please visit:

Substrate Requirements
The substrate must be untreated, dust-free, clean, dry, non-greasy, chemically neutral, structurally sound and absorbent. The minimum temperature for application is 10°C. Wood moisture content < 15%. Do not use on damp wood!

Preparing the substrate / Initial sanding
Completely remove any resin pockets, badly dam-aged old coats as well as old marks, and primers with an acrylic base or unknown composition. For outdoor use: soak any absorbent cutting edges and end grain areas with KREIDEZEIT Resin Oil and allow to dry for at least 24 hours.
Sand down new, weathered or sawn wood (grit P80-100), rounding the edges. Do not use a finer sandpaper as this will make the wood too dense and unable to absorb enough oil. New, smooth, planed or finely pre-sanded wood should be rough sanded to ensure the oil can be absorbed. Dust down thoroughly after sanding.

Putty joints / Glazing
Before sealing the joints with putty, prime them with Base Oil and then treat with a pre-coat of Wood Lazure or Stand Oil Paint, half rich (article no. D 1100-1115).

Single glazing:

Seal the window pane with Linseed Oil Putty. The putty must be painted over after sufficient drying time with Stand Oil Paint or coloured Wood Lazure.

Multiple glazing:
First, apply all coats of the Stand Oil Paint or Wood Lazure, including in the folds, and allow to dry for 5 days at 20°C. Then, install the window pane with window silicone. Silicone cannot be painted over with Wood Lazure or Stand Oil Paint, so it is important to apply it precisely. Please note: white and transparent silicone may undergo yellowing on oil paints.

Processing and drying temperatures:
At least 10°C for a minimum of 48 hours. Only apply subsequent coats once the previous coat has dried thoroughly. When working with the products below, please read the product information beforehand.

Transparent / Varnish Coatings
Primer: Do not prime new or regular absorbent wood. Only prime highly absorbent or weathered wood with KREIDEZEIT Base Oil.
Inside of window: Apply 2 coats, either transparent or tinted with KREIDEZEIT Pigments, using Wood Lazure (article no. 320, 480-488) or with Wood Hard Oil .
Outside of window: Apply 2 coats using Wood Lazure tinted with KREIDEZEIT Pigments or Wood Lazure in Wood Shades.
Do not apply transparent coats of Wood Lazure externally.

Opaque colour Coats
Primer: Prime regular absorbent wood and weathered, absorbent old coats with an oil or alkyd resin base using Base Oil. Do not prime non-absorbent old coats.
Inside and outside of window: Apply an intermediate coat using Stand Oil Paint -half rich-.
Finish satin surfaces with Stand Oil Paint -half rich-
Finish glossy surfaces with Stand Oil paint -rich-.

Diffusion Gradient

Moisture (condensation) frequently forms on the inside of the window. So as not to disturb the moisture balance in the wood, coatings must be at least as permeable or open on the inside of vapour-permeable solid wood windows as the coatings on the outside. It would be even better if the coating on the inside is less permeable than outside. For this purpose, an additional intermediate coat can be applied on the inside of the window with Wood Lazure or Stand Oil Paint, half rich. This intermediate coat is not required on laminated wood, as the glue layers function as a reliable vapour barrier.

Window Folds
The individual layers of paint must be applied very thinly in the window folds. Thicker layers can cause the sash to bond to the frame.
Tip: Keep windows and doors open for at least 24 hours after the last coat of paint is applied. The folds can be rubbed down with KREIDEZEIT Talcum (article no. 997). This prevents new coats from bonding.

Cleaning the Surface
For light dirt, clean only with lukewarm water without any additives. For heavier dirt, clean using Olive Care Soap or Corfu Soap.
KREIDEZEIT Stand Oil Paint and Wood Lazure are environmentally-friendly and are intentionally non-fungicidal. Therefore, it is vital to inspect external surfaces at least every six months for fungus caused by condensation, which usually starts with small black spots; remove these immediately with water and soap.

With a little bit of care, the durability of Stand Oil Paint and Wood Lazure coatings applied outdoors can be considerably increased.
Visually check coated surfaces at least twice a year for impurities and damage.
Do not touch up glossy areas (risk of greasy, sticky surface)!
For areas that have lost their shine, use Care Oil, rubbing very thinly with a soaked cloth immediately after noticing. Then after 10 minutes, rub the surface with a dry cloth until a uniform silky-glossy appearance is achieved. The level of protection and original colour intensity will be restored.
Especially recommended for caring for wooden windows: KREIDEZEIT Window Care Set.

The substrate will need to be re-coated as soon as Stand Oil Paints start to weather severely, chalk intensely or the surface of the wood becomes visible, or in the case of Wood Lazures, the pigments are washed off by the rain. Clean with soap as described above and allow to dry. Very stubborn dirt can be removed beforehand with a scouring pad, abrasive cloth or sand paper (P100). Lightly sand glossy areas (grit P100).

Touch-up coats on Kreidezeit Wood Lazure are applied using Wood Lazure tinted with Kreidezeit Pigments or Wood Lazure in Wood Shades.

Touch-up coats on KREIDEZEIT Stand Oil Paint are applied with Stand Oil Paint, half rich orich.

How often you need to re-apply the product heavily depends on the degree of weathering and the general level of care. There is no specified interval for re-applying coats.

Re-applying coats with Stand Oil Paint, not maintained:
Weathered sides: approximately every 4-6 years
Non-weathered sides: approximately every 7-10 years

Re-applying coats with Wood Lazure, non-maintained surfaces:
Weathered sides: approximately every 2-4 years
Non-weathered sides: pproximately every 5-7 years

Re-coating maintained surfaces:
Many years later. Looking after your surfaces is worth it!