Important Factors To Consider When Choosing Windows For Self-Build - Part 2

HOW TO GET YOUR WINDOWS APPROVED BY YOUR BUILDING INSPECTOR

Although there are certain freedoms when it comes to the design of your windows, you’ll need to ensure that it meets the building regulation requirements specific to your location. Here are a few things you'll need to look out for:

Any glass below 800 millimetres from floor level will need to comply with barrier loading if there’s a change in level outside over 600 millimetres. This is to ensure your window will protect any occupants from falling. The barrier loading can be reviewed by your engineer, or your window company can appoint an engineer on their behalf to review as an additional service. Either way it’s going to be an added cost.

It's also worth noting that any openable windows under 800 millimetres from the floor will need to feature some form of safety mechanism to prevent falling. In England, This could be done through mechanisms such as window stays or locks and is subject to building control approval. Alternatively, you can provide protective barriers, such as Juliets, which act as a safety barrier and can also be a key design feature of the room they serve. Protective Barriers are the only method accepted in Scotland. Juliet balconies affect the operation of the window or door and some manufacturers now offer a fully fitted glazed barrier as part of the unit. Meaning they can operate fully while maintaining safety features and minimise the impact on external finishes as you don’t need to retrofit any external barrier into your newly clad building.

You will need to consider openable windows throughout the dwelling for purge ventilation and fire escape, not all openable windows are equal and you will need to check with your manufacturer if the unit you need to be fire escape is compliant. They will have a minimum unit size they need to meet compliance and can make you aware of what this is. Your architect will be able to advise you on what units require escape based on the fire strategy for your home. 

Your building inspector will also be checking for any trickle vents (if part of the ventilation strategy) to ensure they have been placed correctly and are the right size. Always ensure the free area requirement of the vent can be placed on the window, some units are too small to achieve the minimum standard and the vent fitted won’t be enough to achieve the rate for that room, causing remedial action on site to achieve a compliant ventilation strategy.

If you are building close to a boundary, there may be restrictions on spread of fire and a fire rated unit might be required. This will be raised at design stage with your architect and needs to be considered in the costings when obtaining quotes.

Lastly, always check your planning conditions, some windows placements can cause concern for overlooking and will need to have obscure glazing fitted to satisfy planning. This again needs considered at costing stage to ensure all elements to meet the design intent are considered.

THE COST OF WINDOWS AND HOW TO SAVE MONEY 

When it comes to the cost of windows for self-build, it’s completely dependent on the size, materials, location and number of windows you require. In our 15 years of assisting self-builders realise their dreams, we’ve seen costs range from £30,000 to close to £300,000. Don’t forget to factor in your installation costs when budgeting, too.

Windows are expensive, in fact, they’re going to be your most expensive feature behind the kit itself. If you’re looking to get the costs of your windows down, there are a few methods you can implement

• Stick to the manufacturing constraints and avoid bespoke work where possible
• If you’re planning for a massive feature window, split it in two to save money on the glass panes
• Pick from standard colours and finishes, opting for a non-standard finish can add costs
• Consider alternative material options for your window frame
• Collect different quotes from window suppliers in your area to find the best value
• Consider rationalising different unit sizes, running the same unit size through the factory can help efficiencies at production stage
• Consider salvaging a disused window from an older house. You can browse for these online or visit a salvage shop, but be aware that older windows may not meet the required u-values

WHEN SHOULD I ORDER MY WINDOWS?

The UK is full of reliable and quality window suppliers. Your architect will most likely have a list of window companies they have worked with in the past, so speaking to them to find the right one is your best course of action.

There are plenty of quality window suppliers available outside of the UK but be cautious that their windows are most likely built to a set of regulations different to our own.

We receive a lot of feedback from our clients on the long-term performance of their windows, which helps us to compile the best suppliers in the UK. A few suppliers we use at AC Architects include:

• Internorm is a leading manufacturer of high-performance windows based in England. Check out our interview with them here
• Fakro are one of the leading roof window manufacturers in the UK. Check out our article with them here
• Kloeber is a UK-based company specialising in bespoke, high-quality glazing products. Check out our article detailing their services here

WINDOW SCHEDULES AND MAKING THE FINAL DECISION 

When the time comes to order your windows, you’ll need to work together with your architect/project manager to create a full window schedule. This schedule should include elements such as your thermal requirements, window sizes, material choices, Fire Escape units, glazing options and operation. This schedule should answer any potential question you may have and should be finalised prior to costings if you want a clear comparative quote.

Always get your windows reviewed and confirmed prior to order, there are so many differing tolerances across manufacturers and construction methods that need to be considered. A few of these key factors are listed below:

• If you have a feature glazed gable, the windows will be stacked and may need additional strengthening plates between the units that need considered for final sizing
• Some thresholds to sliding doors are recessed below the finished floor level, which add dimensions to the unit that wouldn’t always be considered
• You may have a spandrel panel in the design  (a window unit that replaces the glass with an insulated panel). They are used to hide any intermediate floor construction behind them and need to be set out accurately for order
• Some manufacturers supply ventilation as standard, which needs reviewed or removed
• The glass thicknesses aren’t always designed for barrier loading and needs reviewed with your engineer for compliance
• Some manufacturers have the opening lines pointing to the hinge and some to the handle, they can also be viewed from the inside or outside, having someone who navigates schedules frequently can help
• Some units are fixed with brackets as some are direct fixed, reviewing the fitting method will help decide on taping and sealing methods
• Full height windows and doors need considered for clashes with ceiling height, taking into account any additional service linings for lighting or recessed curtain tracks
• If you are building a Passive House, other considerations need to be reviewed and you may need a Passive Certified system
  
  

With AC Architects' finely tailored production pack we can include a detailed window schedule and, can oversee the supply of your windows at order stage. When it gets to site, we can fix site visits and review the installation method or provide toolbox talks to ensure the designed specification is carried through to installation on site. This can take a lot of stress from the self-builders’ shoulders and help them proceed through the project with ease.

Choosing the right windows for your self-build project is a crucial decision that impacts everything, from the aesthetic appeal to energy-efficiency. Investing in high-quality, energy-efficient windows can lead to significant savings on energy bills and improve your home's overall value.

Take time to research your options and consult your architect/designers for their advice where possible. By reading this article, you’re already on the right track.

Want to learn more? Contact one of our self-build experts today!