Timber sash windows can be manufactured using engineered softwood or Meranti wood (hardwood) This is a versatile hardwood timber suited to a range of projects where aesthetic beauty is a priority.
Whether your latest project is a window frame, furniture, or general joinery, this straight grain wood is hardwearing and easy to work with. It’s a versatile product that can be machined, sanded, and finished beautifully.
With straight grain consistency, meranti trees produce long, straight pieces of lumber. It’s used for moulding, structure, furniture, cabinets, window, and doors, and veneers for plywood. Meranti is one of the more affordable hardwoods due in part to numerous subspecies, prolific growing characteristics, and availability.
Red meranti trees grow in the tropical rainforests throughout Asia and are famous for their hardwood properties. Red meranti is a classification term based on wood properties like colour, hardness, density and weight. Trees like Shorea leprosula and Shorea ovalis produce top-quality red meranti.
Red meranti is one of the most used and traded tropical hardwoods. It is difficult to work with hand tools because of its hardness and high density. Pre-drilling is always advised when screws or nails are used.
Red meranti wood will absorb paint quick and multiple layers are often not sufficient. It is therefore recommended to use special oils that soak into the wood. This protects it from the elements and gives it nice colourations. Red meranti can be glued well but due to its high density, it is advised to use special heavy-duty glue.
Hardwoods generally come from broad-leafed, deciduous trees such as oak, beech, and mahogany. The thing that defines a hardwood from softwood is the presence of special pores in the cellular structure of the wood itself. Their complex cellular structure gives them great dimensional stability and durability. Hardwoods are used in everything from musical instruments, boats, tools, and of course, windows.
Traditionally, all sliding wood sash windows were operated by cast-iron weights. Nowadays there is a modern spring mechanism option. We look at both types for wooden sash windows.
Wood Sash Windows on Weights
A sash box of 98mm is built into each side of the window, which houses the weights. This is attached to a piece of sash cord, which travels over a pulley in the top corners of the window and attaches to the sash that’s sliding. The sash windows using weights is selected to closely match the weight of the sliding sash so that a perfect counter-balance is achieved and movement of the otherwise heavy window sash is as effortless as possible.
The use of weights and pulleys in modern sliding sash windows has declined over recent years and has largely been replaced by the spring balance system. Sash windows on springs work using similar principles of counterbalancing but achieve it through the use of two springs inside a PVC tube. Spring balances are usually visible on the inside of the window. However, a cover paint matched to the window will offer total concealment when manufactured. This makes the windows with spring balances almost perfectly reflect the style of those with weights and pulleys.
To help in opening windows, as well as hold windows open and closed, spiral balances utilize a spiral-shaped rod within a tube. This rod connects to a spring, which provides the tension for supporting the sash. The tension is adjusted by being wound the sash it is supporting.
Should I choose weights or springs?
Both systems have pros and cons, and the right system for you will depend on your location, the reveals in the window opening, and the desired impact you are trying to achieve. Weight and pulley systems have a nostalgic and historical feel, they’ll fit neatly behind traditional reveals, these systems also last longer (many decades) and repair means simply fitting a new sash cord. Spiral balances systems fit neatly into all building/reveal profiles without reducing light.
Looking for a decorative finish to enhance your project, for all interior and exterior decoration in London we recommend Chelsea Decorators