## What U-Value Should your Timber Windows Have?

When you are looking for a new set of Timber windows, there’s one metric that you’re almost certain to encounter, the ‘U’ value. This number is a way of describing a window’s thermal efficiency, but what does it mean? What is the best U-value Timber window, and what is the U-value of double glazing?

How Does U-Value Work?

A U-value is a measure of heat energy moved through a given area of material in a given period of time. This might be a Timber window, but it might equally be a wall or a door. It’s most often measured in watts per metres squared, when the difference in temperature between the two sides is one-degree Kelvin. Given that that’s a bit of a mouthful, we tend to say ‘W/m2K’ instead.

It’s important to note here that the U-value of a given window refers to its efficiency per square metre. So, two windows might have the same U-Value, but transmit heat at different rates because one is a different size to the other.

The lower its U-value, the better an insulator the window will be. If you’re aiming for the most thermally efficient house possible (as most of us are, cost permitting), you should almost always go for the Timber window of the lowest U-value.

How to Calculate the U-Value of a Window

If you’re buying a new Timber window, you’ll be able to see its U-value advertised by the manufacturer. Unfortunately, calculating a window’s U-value yourself isn’t particularly easy, nor are your calculations likely to be totally accurate.

For example, not every glass panel is manufactured to the exact same standards, and what stacks up in a laboratory might not translate into the real world. While there are bodies like the BFRC (which we’ll discuss in a minute) there to maintain quality standards, it’s important to treat claims about efficiency with a degree of scepticism.

Secondly, the glass panel isn’t the only thing you need to consider – the window frame also conducts heat, and will contribute to the thermal efficiency of the window. While it’s possible to account for this in your calculation, given that the interior of a window frame is made from a range of different materials, doing so can be very difficult.

To comply with building regulations, windows (like every other element of your property) must meet a certain minimum U-value. In the case of a window, it’s 1.6 W/m2K. Double-glazed windows, filled with argon, are typically 1.4 W/m2K, while thicker triple-glazed windows can go as low as 0.7 W/m2K.

The British Fenestration Rating Council provide a colour-coded rating system to help homeowners distinguish between different qualities of window. Good windows which keep the heat in are rated A or above. Bad ones are rated E or below. While this rating system is easy to follow, and will prevent buyers from making a mistake they will regret for years, it isn’t quite as specific as the U-value. As such, when you are looking for windows, we’d suggest looking for the U-value and spending your money accordingly. Obtaining a quote for windows with a good u value is easy.

Ultimately you will need to look beyond the lettered rating, and look at the U-value.

## Engineered Softwood Timber Windows

Educate yourself about the engineered softwood used to manufacture Timber Windows

Softwood Engineered Timber Windows

This is the only softwood that we recommend using as it is ‘engineered’. This is a process where several pieces of softwood are glued together with opposing grain directions to form a single ‘laminated’ piece, this in turn leads to a very stable product, far outperforming solid generic softwoods. Less movement in the wood means that the paint or finish doesn’t have to flex as much, ultimately leading to longer periods between re-finishing and maintenance of your windows.

The process of bonding timber together to create a component that can be used in windows, doors, conservatories or stair cases has been used for over twenty years. However, it has only been in the last ten years that we have seen significant improvements with large European joinery companies investing in the equipment to produce laminated or engineered components in hardwood or softwood to compete against products offered by companies selling UPVC and aluminium clad systems.

The UK window and door market has been dominated by UPVC and composite products for the past 15 years. However, with the increase in availability of laminated timber components this has allowed the larger joinery manufacturers to produce high performance windows and doors in timber that offers a sustainable and attractive alternative to plastic or aluminium.

Why use Engineered Timber?

• Timber bonded together in thickness and/or width offers greater stability over solid timber. • Wastage is reduced significantly during the manufacturing process, due to specific width and length availability. • Reduced production costs including labour. • Significant improvement in quality (defects removed) • Full utilisation of every component purchased. • Reduced stock holding • Reduction in waste removal.

Contact us for a quote to see for yourself how competitively priced our Timber windows are in comparison to UPVC.

www.timberwindows-direct.co.uk

## Timber Windows – London

#### Timber Windows are an exquisite feature of any modern-day London property.

timber windows

The period properties found in this area of the country are iconic with their large Timber Sash Windows and the history of them is rather grand.

Timber Sash windows are first believed to have been used in the late 17th century. Earlier than this heavy timber casement windows were normally used. In the early eighteenth century, the superiority of the timber sash window meant that sash windows became predominant, in fact some owners of houses of earlier dates, replaced their casement windows with timber sash windows. This can lead to 16th and 17th century houses being mistaken for Victorian properties.

Some of the very earliest sash windows did not have weights and pulleys, but more often the lower sash was held up using timber wedges.

The window tax of 1746 was repealed in 1851, as a result of this house builders started using more timber windows and the popularity of the Timber Sash window boomed especially in London.

In the Georgian period, smaller panes were used in the sashes. Typically, this was 6 panes over 6 panes, although larger timber windows would have had to use more panes simple to cover the size of the apertures.
During the Victorian period the development of polished sheet glass in 1838 revolutionised the manufacture of Timber Sash windows, the use of larger sheets of glass became possible, with fewer glazing bars. This coincided with the use of “horns” to strengthen the frame.

During the 1870’s four paned timber windows became the norm, followed by 1 over 1 sashes. A late revival in the use of smaller panes took place at the end of the 19th century, along with the use of multi-paned upper sashes over single paned lower sashes.

Please feel free to get in touch with us to obtain a quote for Timber Windows.

## Timber Windows are preserved, painted and finished in 5 stages:

Stage 1) The first Chemical preservation stage is completed by direct dipping of the timber window into the preservative solution to protect against moisture absorption.

Stage 2) The second Chemical preservation stage is completed by direct dipping of the timber window into the preservative solution to protect against fungi, pests and mould.

Stage 3) Primer and Undercoats are applied.

Stage 4) First top Coat is machine sprayed to frame.

Stage 5) Top Coat is machine sprayed onto the frame.

## The process of “Dipping”

Dipping

The Dipping process consists of simply immersing the wood in a bath of creosote or other preservative for a few seconds or minutes. Similar penetrations to that of brushing and spraying processes are achieved. It has the advantage of minimizing hand labour. It requires more equipment and larger quantities of preservative and is not adequate for treating small lots of timber. Usually the dipping process is useful in the treatment of window sashes and doors. Treatment with copper salt preservatives is no longer allowed with this method.

Timber Windows

## Our Colour Palette

Here at Timber Windows Direct we use the Classic RAL colour chart.

RAL is the most popular Central European Colour Standard used today, The colours are standard for use in architecture, construction, industry and road safety.

RAL is a colour matching system used in Europe that is created and administrated by the German RAL gGmbH[1] (RAL non-profit LLC), which is a subsidiary of the German RAL Institute. In colloquial speech RAL refers to the RAL Classic system, mainly used for varnish and powder coating but nowadays there are reference panels for plastics as well. Approved RAL products are provided with a hologram as of early 2013 to make unauthorised versions difficult to produce. Imitations may show different hue and colour when observed under various light sources.

Why not obtain a quote for timber windows in a RAL colour?

## Obtaining a quote for Timber Windows has never been easier.

The old method of contacting a window company to attend your property and measure up whist providing you there highly polished sales pitch is now redundant in our opinion!

Online sales of everything has taken a huge leap in recent years and buying timber windows is no different.

When customers start their journey for purchasing windows they generally have a very good idea as to which windows they want to buy.

We believe that it is not necessary to attend people’s property and present the highly polished sales pitch in order to put pressure on people to buy windows and doors.

Timber Windows Online

Here at Timber Windows Direct we started sales via EBay and have grown into a very respectable online business.

Customers can roughly measure up their own windows to provide us rough measurements to quote them on – we will then attend the property and complete a full window survey to ensure the production measurements are correct.

This process removes the pressurised sales techniques that some companies use.

www.timberwindows-direct.co.uk provides many photos of our completed projects and the various types of windows that are available to the customer.

We are more than happy for our potential customers to come and see us and view our windows prior to placing an order as we are fully aware that some people wish to see the finished product prior to committing to an order, we are based in Bracknell Berkshire so please come and see us if you wish?

If you genuinely feel you need to have someone attend your property and conduct a full window survey then please get in touch and we will arrange for someone to attend and measure up but rest assured it will come with help and recommendations but no polished sales pitch!

## Timber Windows – Fire escape measurements.

### What are the requirements for my Timber Windows to be fire escapes?

General criteria for egress Timber Windows:

• Width and Height of Timber Window – Either of these are not to be any less than 450mm
• A Clear Openable Area – No less than 0.33m²
• Sill height – The bottom of the openable area should be no more than 1100mm above the floor area.
Only one window per room is Generally required, but you should refer to the approved document B to ensure you are compliant with building regulations.

#### Here at Timber Windows Direct we have made this simple for you.

The Minimum width and height for our sash windows to obtain a clear openable area of 0.33m2 are as follows}

Timber Sash window on Weights will need to be 650mmW x 1250mmH or greater.
Timber Sash window on Springs will need to be 580mmW x 1215mmH or greater.

IMPORTANT: IT IS NOT ENOUGH TO HAVE A WINDOW WITH DIMENTIONS OF 450mm X 450mm AS THE CLEAR OPENABLE AREA MUST BE NO LESS THAN 0.33SQM

Why not request a quote for Timber Sash windows at http://www.timberwindows-direct.co.uk

## Timber Windows and FENSA Certificates

### When do you need a FENSA certificate?

We often get asked by our customers if we can supply a FENSA certificate when supplying Timber Windows.

There seems to be some confusion over what FENSA actually is, plus how it is relevant to works being carried out in your home.

Even with a cursory glance at the FENSA website, It states that, FENSA is a government authorised Competent Persons Scheme for the replacement of windows and doors in England and Wales.

I will clear up any confusion…….. Enabling those purchasing Timber Windows to understand when a FENSA certificate is required.

### What FENSA actually is?

FENSA stands for, The ‘Fenestration Self-Assessment scheme’ which has been set up by the Glass and Glazing Federation (GGF). As a means to self-certify compliance under Building Regulations, without the need for a separate assessment from Building Control.

If your installer is not registered with FENSA. All works that include replacing windows and doors will require you to get a certificate from Local Authority Building Control instead.

### When does FENSA apply to your Timber Windows?

FENSA does not apply to conservatories, porches, commercial premises, new build properties or extensions.

In all of these instances you are required to go through the Local Authority Building Control process.

### So, in summary ……….

If the Timber window or door is a new addition to your property, or the building itself forms part of an extension, or is a complete new build, then FENSA does not apply and you will require approval from Building Control.

If you are replacing an existing window, you can use a FENSA approved installer or alternatively apply for full Local Authority Building Control approval.

Please note that the homeowner is ultimately responsible for ensuring that their window or door installation complies with these standards and regulations.

Visit Toughened safety glazing – Building Regulations for information regarding building regulations.

## Trickle Vent or no Trickle Vent?

### Do we add a Trickle Vent that is the question?

The use of a Trickle Vent is often pondered over for a considerable period of time. Some people consider them an addition to a window that is not astetically pleasing but it may be essential!

Here at Timber Windows Direct we manufacture our windows with the lowest profile vents possible to minimise the look of the trickle vent. They are finished flush with the window as opposed to competitor versions which stick out as a whole unit.

The trickle does have a very practical reasoning behind though and this article in the Telegraph sums that reasoning up nicely…

### Ventilation

Windows and doors provide ventilation to rooms within a dwelling and rules apply to how much ventilation is needed. The type and extent of ventilation will be dependent on the use and size of the room.

For example, rooms where steam will be produced (kitchens, bathrooms, utility rooms etc) should be provided with higher levels of ventilation (normally mechanical fans and windows) than other rooms where suitably sized window openings and background (“trickle”) ventilators may suffice.

Still can’t decide?

Get in touch and we will endeavor to help you make a choice.

## Toughened safety glazing – Building Regulations

### Toughened Safety Glazing and Building Regulations

Toughened Safety Glazing is a very important factor in modern building regulations. You will need to take this into consideration when replacing your Timber Windows and Doors. You will also need to ensure you are complying with relevant regulations as Dwellings are required to be energy efficient.

### Energy Efficiency

A method of achieving greater energy efficiency is to take steps to reduce the amount of heat that is lost through the glazing in both Timber windows and doors.

If you are to install windows and doors you should be aware that they need to comply with the requirements of the Building Regulations in relation to the amount of heat that can to pass through the glass and framework, which is measured as a U-Value.  This U-value should not be exceeded.

## Increase property value with Timber Windows

### Increase property value with Timber Windows

It’s a fact! Timber Windows are proven to increase property value and the cost of this refurbishment is surprisingly lower than you would expect!

If you purchase your Timber windows from a supplier and then hire a carpenter or window fitter to install them the price of the total refurbishment would be lower than if you requested a large national windows company to supply and fit them for you.