We do Windows and Doors too!

Windows and Doors

It’s easy to get distracted by our gorgeous Log Cabins, Summerhouses, Climbing Frames, Garden Offices and Gazebos. So occasionally we like to remind you that we started out selling uPVC windows and doors – things we still do today. When many companies are ceasing trading, retiring or moving to other markets, our windows and doors business is stronger than ever.

Windows and Doors


Starting in 1994, over 20 years ago, we started producing fully tested and certified energy rated windows. The Window Energy Rating System, which is based on a scale from A to G, helps distinguish windows that are energy efficient. Not only that but certified energy efficient windows have other key benefits that are must haves in domestic windows such as increased insulation to help improve heat retention and keep your family warm.

This heat retention also helps to reduce your energy consumption, lowering your energy costs. All you need to do is make sure the windows and doors match building regulations. The rules are all based on the situation. So a window that might pass building regulations for one location will not for another. This might seem daunting but do not worry! In this blog, we will try to simplify the main issues so you are aware when looking to comply with building regulations.

The main areas to focus on are:

  1. Safety from impact (Part K Building Regulations)
  2. Ventilation (Part F Building Regulations)
  3. Fire Escape (Part B Building Regulations)
  4. Insulations (Part L Building Regulations)

It may be there are additional restrictions on your property, such as sound insulation in noisy areas (you can find out more on the FAQ section of our website); it is always worth giving your local building control officer a call, they should be able to give you advice regarding building regulations. The responsibility for meeting building regulations lies with the person installing the products and the landowner. So if you are installing yourself, you need to ensure your choice of style and options result in your windows and doors meeting the rules above.

If you are paying a professional installer to install the windows, if know their trade properly, they’ll refuse to install any windows that do not meet the requirements for your home – much better to take the time to work out what you need and choose the right options for your situation. So what do you do once you are sure your windows and doors comply? For a small fee your building control officer will be able to inspect your windows and doors after installation and provide you with a certificate to show you have made the right choices. This will be needed when you come to sell your house. Windows and Doors

How well insulated do my windows and doors need to be? (Part L Building Regulations)

In order to help protect the environment and to keep energy bills low, the requirement for energy efficiency in windows has been getting more and more demanding over time. Replacement windows are now required to meet an energy rating of Band C as a minimum. Doors are required to have a U-Value of 1.8W/m2 (a U-Value is a measurement of the amount of heat lost per unit area.

The lower the number, the less heat lost.) All Dunster House windows and doors meet these requirements, using energy efficient 5 chamber profile system and Low Emissivity Planibel A glass, so you can rest assured you will be fine on this requirement of building regulations.

It is, of course, possible to get windows that are even better for energy efficiency, even going as far as the expense of A Rated triple glazed windows. But you have to consider the expense vs the benefit. If you are replacing windows and doors in anything except a modern built house, then the chances are there are other more cost effective changes you could make. R

ather than spending the £1000s extra on triple glazing, a Dunster House window will provide excellent insulation, get you through the building regulation requirement and then you can consider spending the savings you make on upgrading the wall insulation levels, or insulation for the roof.

In order to show to your building control officer that the installed windows meet the required level of insulation, each Dunster House window is provided with a conformity certificate to demonstrate it has been made with the correct materials and to the correct design to ensure conformity to the Building Regulation insulation requirements.

Why do we use toughened glass? (Part K Building Regulations)

The reason you might need toughened glass is due to Part K Building Regulations (Part N in Wales)[i]. More information can be found on the UK Governments Planning Portal website here. These provisions are all about protecting you or your family if one of you were to run in to or trip in to a glass window or door, and it is required by law that certain “at risk” areas are made from toughened glass. Toughened glass is not indestructible.

It is stronger than regular glass but it can still break. The reason it is safer is that if it does get hit hard enough to break, it will crumble in to lots of tiny pieces, rather than shattering in to large dangerous shards of glass. This is why it should be used on glass areas where someone might trip or fall against it. The rules are actually very simple (Section K4 of Part K): If any part of the glass is within 800mm of floor level then that whole glass section will need to be toughened. If the glass is part of a door or is within 300mm of a door, then if any glass section is within 1500mm of floor level then that whole glass section will need to be toughened.

So if all or just part of the glazed area is within the shaded area that requires toughened glass then you need to ensure you buy toughened glass for that location. As you can see there are location that do not require toughened glass, these are illustrated as numbers 1, 3, 9 and 10. Most standalone windows do not require toughened glass; these being windows that are over 800mm from floor level and are not within 300mm of a door. To make this easier for you, we do the following:

  • All the glass on any of our doors is toughened. It is included in the price, you don’t need to worry about paying more (fixed glass sections above the door, such as labelled “3” on the diagram may not be toughened, since they are not required to be).
  • All side panels for doors are also automatically toughened, included in the price (as these are generally within 300mm of a door).

On any of our windows, with one easy tick you can choose Toughened Glass and the whole window will be made with toughened glass. Windows and Doors

Do you need trickle vents? (Part F Building Regulations)

As time has gone on, we have gotten better and better at making our homes insulated, putting draft excluders on doors, sealing all the gaps, making our homes practically hermetically sealed. But this has actually had a downside. Human beings are pesky creatures that just keep breathing.

And every time you breath out, an area the size of a tennis court that makes up the surface area of your lungs is evaporating moisture (go breath on a piece of cold glass and you’ll see what we mean!) In our modern sealed homes, this moisture has nowhere to go, building up in the corners of rooms and often being mistaken for damp. This moisture can damage our property and our health if mould starts to grow. Dunster House windows and doors are great, with gasket seals to stop drafts and meeting all the latest regulations required for insulation.

But then how to do we stop this moisture building up?

Simple, we can provide optional trickle vents to each window. A trickle vent is a simple aperture to allow air to circulate between the outside of your house and the inside of your room. It can be opened or closed by the user. Part F of building regulations covers the need for ventilation and it can be found on the governments planning portal website here. As part of this document, it is required that kitchens, bathrooms and utility rooms have ventilation but this would normally be covered by a fan.

This would also normally mean that, assuming you have an adequate ventilation fan, you would not need trickle vents for your windows. For all habitable rooms, tickle vents are required for what is called whole building ventilation (For very new houses you may have a whole house ventilation system and not need trickle vents either). A habitable room is a room used for dwelling purposes but which is not solely a utility room, bathroom or cellar. As always with building regulations, documents are long and complex. The most likely recommendations are:

  • Choose trickle vents for all rooms except hallways, bathrooms, utility rooms, kitchens or cellar.
  • For bathrooms and kitchens, you also need ventilation but you will normally have a fan. If you do not, you will need to consider ventilation for these areas as trickle vents through windows may not be sufficient.

And if you have any questions, just ring your local building control office – your council is supposed to be there to help with things like this!

Do you need a fire escape window? (Part B Building Regulation)

This building regulation is another sensible one there for our protection. We can become so obsessed with security having smaller and smaller opening windows to stop burglars getting in, but what happens if we need to get out? What happens if a fireman needs to get in through the window to rescue someone? As we will see later, it is actually this consideration that sets the sizes for fire escapes. It is also the case that our obsession with keeping energy bills low has previously led to houses designed with smaller and smaller windows. You may see some houses built in the 90s that have very small windows, as it is easier to insulate a wall than it is to insulate glass.

A lot of these windows simply wouldn’t be allowed now, due to changes to the rules requiring fire escapes. Luckily improved glass technology now gives greater insulation than ever before, meaning larger windows can be made to create a fire escape while still providing thermal insulation. When replacing a window, it is important to consider the fire escape requirements. So when do you need a window to count as a fire escape? Part B of building regulations covers fire safety for dwelling houses. It can be found on the governments planning portal website here. For a simple 1 or 2 storey house, the provisions are quite simple. If the building is larger than this, for example, a block of flats, then exit becomes more hazardous (for obvious reasons) and you should consider carefully your windows and doors along with an overall plan for fire escape.

For a simple 1 or 2 storey home:

  • All habitable upstairs rooms must have a window suitable for fire escape.
  • All habitable rooms on the ground floor must either have a fire exit or have direct access on to a hall leading to a fire exit.
  • An inner room is a room where you would need to go through another room (an access room) to reach a fire escape. An inner room like this would require its own fire escape. However it is acceptable to not have a fire escape if the inner room is a kitchen, laundry or utility room, a dressing room or a bathroom/WC/shower room. So this means your en-suites are fine without a fire escape window.

So how can a window be a fire escape?

Building Regulations Document B states:

“The window should have an unobstructed opening area that is at least 0.33m2 and at least 450mm high and 450mm wide (the route through the window may be at an angle rather than straight through). The bottom of the openable area should be no more than 1100mm above the floor.”

This is actually all quite sensible and quite easy to achieve. Note that the opening area must be at least 450mm wide.

Combined with the width of the frame and sash, the size of a side opening window will need to be 650mm. So if you chose an Egress hinged window. A special hinge designed to open the window wider than a normal hinge. The opening size will be set to 650mm and the hinges will open out to 90?

The perfect fire escape window.

If you have an older house, and perhaps you are replacing a sash window. You might find a window with a lower opening section better for your needs. Remember that you must ensure the opening area starts within 1100mm of the floor: It is as simple as that. By paying attention to the requirements for the room you are fitting the window. Also, carefully setting your hinge option and opening size accordingly. You can ensure the window you choose will be considered a fire escape.

Windows and DoorsFor more information on Building Regulation Requirements for our windows and doors, please see our other FAQ articles. To give your house the revamp it’s desperately needing, visit our website or call our sales team on 01234 868628.

[i]Remember, Dunster House do not know where you are fitting your windows. It is up to you to choose Toughened Glass when you require it for your situation.

July 9, 2016

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