Durable Windows Limited Guarantees and Maintenance Guide

Preservation - 20 years against preservation failure

Paint Finish - 6 years manufacturer guarantee against paint coating system failure, 10 years if installed by DW.

Stain/varnish Finish – 2 years manufacture guarantee against stain coating system failure.

Glazing Unit – 5 years supply and installation, Weather seal – 5 years manufacturer backed guarantee

Hardware – 5 years supplier backed guarantee

Spiral balances – 15 years manufactures guarantee

The above is valid only if the windows are properly maintained and all damages repaired immediately. You must follow the windows maintenance guide below:


You should aim to inspect your windows every year:

1. Check for any open joints on box frames and sashes

2. Check for cracks or gaps between putty and glass internally and externally

3. Check for peeling or loose paint which may trap moisture

4. Check frame perimeter for gaps

5. Check condition of sash cords

6. Check locks

7. Check for any damages, they have to be repaired immediately to retain warranty.

Typical sash window problems likely to be encountered include:

  • Cracked and flaking paintwork: normally the outside of the windows should be repainted at intervals of five to eight years.
  • Sticking windows: usually the result of either careless replacement of staff bead, following repair or re-cording, which is easily remedied, or a buildup of paint which needs to be removed.
  • Failed putty and broken glass panes: these are relatively easy to replace.
  • Broken cords: in former times people re-corded their own windows – the cords and sash weights were available at many tool stores (and still are at some).
  • Timber decay, particularly to the bottom rail: fillers are invaluable for minor decay and surface imperfections where the strength of the timber is unaffected. Loose corner joints can be strengthened by means of corner brackets which can then be painted over.

Windows facing South and West will need more attention as they are generally more exposed to the weather. Often, all the windows will not need painting at the same time. The most exposed windows may need painting every 5–6 years (or 2 years if varnished, 1 year if oiled) and sheltered windows often last 8–10 years or even longer. If you can't fully repaint before winter comes, get some paint on exposed areas.

Make sure that dirt is cleaned off. Avoid stripping paint back to bare wood. It seldom helps redecoration and can cause more problems than it solves. Small damaged areas in the finish such as nicks and scratches may be touched up with a matching high-quality latex primer and paint.

Contact your local paint supply store for product recommendations and instructions. Use the best paint your budget will allow. Ideally apply two coats: undercoat and top coat. The best finish follows on from proper preparation. For your own safety, if you wish to tilt or remove the sash of your sliding sash window but the sash seems larger than you can handle, we strongly suggest you get a second person (ideally a professional) to help. Windows and doors tend to rot at the bottoms of the frames and the side stiles.

Poke around with a screwdriver to find rot. If you find rot make sure that it is properly dealt with. Get back to good timber, fix the timber using a hardening compound and then fill it using quality filler. Often the best solution is to have a joinery professional make a splice repair.

More significant repairs can be carried out by any competent joiner.

Window cleaning

Periodically clean the vinyl jamb-liners where the sash slides. Keep them dirt and grease-free by washing with a gentle washing up detergent and after drying, spray with furniture wax to prevent sticking. Be sure to wipe off any excess wax. Superficial surface dirt can be removed by washing with water and a soft bristled, long-handled brush (such as those used for washing cars) or using warm soapy water. Heavier accumulations can be removed with a mild solution of household detergent. Other cleaning solutions consisting of alcohol/water mixtures are also effective. As with any cleaning operation on a vertical painted surface, streaking will be minimized if the surface is washed from the top to the bottom. Always rinse the surface well with clean water to remove excess detergent solutions or cleaners. Prolonged detergent contact with paint can cause damage to the finish. North-facing side of buildings is predominately colder and damper. These conditions are ideal for the growth of algae/mould, and if not removed will damage the coating. Treat northern windows with a solution of one part household bleach to two parts water; allow the solution a minimum of 20 minutes to work before washing off with clean water. A nylon bristle (not metallic) brush should be used. This should be done on a regular basis, which will be determined by how quickly algae or mould build up. Grease or oily materials may require the use of stronger cleaning compounds. Solvents or abrasive-type cleaners should be avoided. Do not allow strong detergents, ammonia, chemicals or other harsh cleaning substances to come in contact with finished exterior surfaces as they can cause damage. Depending upon location and frequency of use, lubrication of the internal mechanism of spring balanced sash window balance may be desirable after a length of time. This period will vary according to site circumstances. A few drops of light machine oil or spray such as WD40 applied via the top end of the balance tube will always improve the operation action of a balance after long service. Friction hinge tracks of casement windows should be kept free of dirt by a small brush and “blowing” the dust out of the track. Keep moving the casement so different areas can be cleaned. Remove all dust, grit, before lubricating pivot points and all other moving parts with light machine oil which should been done annually.

Brass hardware

Some windows and doors feature solid brass hardware. These locksets are highly polished, then coated with a lacquer finish. Hardware finish life can be affected by use, solvents and exposure. When the finish is worn down, the brass is exposed and will tarnish. This is a natural property of solid brass and is not considered a manufacturing defect. However, proper care for solid brass hardware will delay tarnishing and offer years of beautiful service. Whether brass hardware is on the inside or outside, the lacquer finish will eventually wear down and expose the brass underneath, leading to some degree of tarnishing. The extent and rate of tarnishing depends on factors such as the levels of use and exposure to pollution, UV rays and salty sea air. With a little care, tarnish can be eliminated from your brass hardware. First, remove all remaining lacquer finish by using a steel wool (available at hardware stores) soaked in a light oil or soapy water to keep metal abrasion to a minimum. For tough-to-clean hardware, try washing with a high quality lacquer thinner or paint reducer. Be very careful not to get any on the door to prevent damage to the door or window finish. Once the hardware has been cleaned, the shine can be restored with brass polish. After polishing, protect the shine with several coatings of quality automobile wax. The finish can be protected on an ongoing basis by applying follow-up wax coatings as needed.

What if…

…windows stuck shut?

Scrape off any paint build up which may be preventing movement and spray Silicone spray into the moving parts. Silicone is the modern beeswax. If the timber has expanded to the extent that the windows does not open or close without forcing, get a professional help.

…glass or cords broke? Cracked glass, broken sash cords or defective hardware is rarely cause for concern and can usually be repaired inexpensively. It is the structural integrity of the joinery that is the most important element. If beading, architraves or liners are broken or defective, it is often less expensive to replace them than to repair.

These parts can be found in most of DIY stores.

Remember that timber windows and doors installed many years ago are still giving good service. Take a proper care of them and they will be at your service for life.