How to Maintain Crittall and Metal-Framed Windows | Glaze & Save

Properly maintained Crittall or metal-framed windows can last for decades if not centuries and have the potential to create a stunning façade in historic buildings. However, to ensure that your metal-framed windows stand the test of time it is important to understand the best way to maintain and care for them. Luckily, we have some handy tips to help you maintain your metal windows to keep them efficient, in-tact and looking good for years to come.

Background

Metal-framed windows date from the mid-16th century and were popular until the 18th century until they experienced a resurgence in popularity during the Victorian age. Prior to the 18th century, metal-framed windows were individually crafted, usually in wrought iron, cast iron or mild steel, and required an intense amount of skill on the part of the craftsman to create each window.

However it was with the pioneering technology of Sir Henry Bessemer , who innovated a process for producing cheap mild steel in the 1850s, that metal windows became a commercially viable product to produce en masse in a factory setting.

The market for steel windows came to be dominated by the main manufacturer of the time: Crittall Windows Ltd. The origins of Crittal Windows Ltd go back to 1849; however, it was not until 1884 that the company began to manufacture metal windows, they’re name becoming synonymous with metal framed windows whether produced by Crittall or not!

Common Problems

With proper maintenance and care, metal windows can last for centuries and often remain as the most prominent sign of a buildings history and original fabrication. However, when protective coatings are not tended to corrosion of the fabric of the window can occur. This is particularly true in the case of pre-1950s ungalvanised steel windows, where corrosion and rusting can be seen mostly frequently, although wrought iron and cast iron frames can also be affected. The Society for the Prevention of Ancient Buildings (SPAB) details the effects that this corrosion can have on the integrity of the windows:

“Corrosion leads to the loss of original material, staining on adjacent surfaces and, as the metal expands, cracked glass and split masonry at fixing points (the latter being termed ‘rust jacking’).Other potential problems include the fracturing of cast iron because of impact or casting flaws, and the distortion of wrought iron or mild steel following forcible closure of casements where there is paint build-up.”

Routine Maintenance

Corrosion and degradation of metal-framed windows can be avoided by engaging in regular routine maintenance of your windows. The following work should be carried out on a regular basis :

· Opening Casements should be regularly checked to ensure they are free of grit, dirt, insects and paint flakes;

· Hinges and pivots should be lightly lubricated on an annual basis to ensure their smooth operation, although it is  worth bearing in mind that lubrication is not recommended for friction-type hinges which may swing too freely if lubricated;

· Weatherseals should be inspected to ensure unfettered operation, and any traces of paint removed as this is the most common cause of failing weatherseals;

· Putty, mastic, etc should be inspected on an annual basis and removed and replaced if required.

Dealing with Rust

Homebuilding.co.uk provides a handy step by step process to dealing with remedial rust issues, where full restoration is not required. Where the rust only affects the surface of the window this can be removed with a wire brush; however it is important to take precautions where it is suspected that red lead may have been used as a primer. If the rust is superficial and easily removed with a brush then it is important to apply a good quality zinc primer to the frame. Stripping multiple layers of old paint from your metal windows may also help increase their functionality, but again, caution is advised where there is a possibility that lead paint may have been applied to the window in the past.

In the event that rusted sections are corroded through, wrought iron window sections can be cut out by a professional and welded back in. However, cast iron is almost impossible to weld and may require cold-metal stitching.

Dealing with Draughts

With corrosion, warping and generally inefficiency of older glass technologies, metal-framed windows can be extremely draughty. SPAB recommends that in draught proofing metal framed windows the opening casements require to be eased and adjusted to ensure that the window is optimally positioned for draught proofing. If draughts are still an issue this can be remedied by applying a silicone draught proofing product in the gap. This is where a product such as Glaze & Save’s InvisiSeal™ comes into its own, as its non-invasive liquid silicone fabrication means that it can fill any gap in the frame, creating an air tight seal while remaining virtually invisible.

Crittall windows are also especially well served by secondary glazing, as the application of a supplementary glazing system can tackle the draughts, energy inefficiency and noise issues that are characteristic of older metal-framed windows. While traditional secondary glazing would require a clunky frame to be constructed around the outside of metal frame, Glaze & Save InvisiTherm™ is a discrete design that can be installed inside the window frame, or when in conjunction with InvisiSeal™ draught proofing, can be applied directly to the glaze, keeping your metal-framed window entirely in-tact and colour matched so as to be virtually invisible.

Protect your windows and experience a warmer, cozy and more thermally efficient home with InvisiTherm ™ the all-in-one window solution. Reduce heat loss by 63%, Reduce noise by a minimum of 48%, eradicate condensation and draughts, and completely eliminate ultraviolet fading, all without the need for any permissions. Retain your original windows and full working shutters while turning your single glazing into double glazing. Contact today on 01738 562 068 or via our contact form to find out more and arrange your free survey.