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How to Build a Sustainable Home Part 1: Fabric

Planning to create a sustainable house for your family to live in? Whether you’re building an energy efficient home from scratch, or carrying our eco-friendly renovations on an existing property, you need to begin by considering the fabric of your building.

The way your new or existing property is constructed is crucial. You need to assess the opportunities for boosting energy efficiency of the property, while minimising any environmental impact you make, to create as sustainable a building as possible.

To build a sustainable home you need to consider the four Rs of sustainability:-

  • Reduce
  • Reuse
  • Recycle
  • Recover

This series of blogs will run through some of the key aspects to consider to help you build your sustainable home.

Consider Your Construction Method and Materials

The construction method and materials you use for your building fabric envelope is probably the most important decision you will make when building a sustainable house. The most energy efficient homes are well insulated and extremely airtight, and therefore require very little heating or cooling.

Gone are the days where almost all houses are built of bricks. If you are building a brand new home then ICF (insulated concrete formwork) and SIPs (structural insulated panels) are a good choice, as they can easily be made very airtight. It’s also worth considering using a timber frame construction, as they tend to be more highly insulated as standard, and the precision nature of the build means they can have better air-tightness than masonry. Brick and block construction is much more difficult to make airtight, and the materials themselves take a lot of energy to produce.

Sustainable homes should also be built if possible using sustainable resources – such as wood, hemp and straw, alongside recycled and reclaimed materials. Bricks and blocks are not considered to be very sustainable (unless they are reclaimed), although locally sourced stone is sometimes a good alternative. SIPS and Timber frame homes use wood, which is an environmentally friendly choice. While concrete itself is not sustainable, and its use should be minimised where possible, there are ICF wall units on the market which are formed from a cement-bonded recycled wood waste fibre – known in the trade as ‘woodcrete’.

N.B When you’re building or renovating, it’s amazing how much of the materials you need can be sourced locally, which is better for you, and in the long run better for the environment too. Try looking for sustainable, natural resources closer to home. If you find yourself with excess materials during your renovation, research where you can dispose of them sustainably. There are many local charities that recycle building materials such as wood and paint. You could also give them away to a friend, or via an organisation such as Freecycle. You could even try your luck with selling them on. Always use a reputable skip company – they will recycle as much of the waste you produce as possible. Only send your waste off to a landfill if you’re sure it can’t be helpful somewhere else.

Boost Your Insulation levels

One of the best home energy efficiency improvements you can make is to increase your property’s insulation levels. There are many simple, yet effective ways to insulate your home, which can make your home more sustainable – and more comfortable too. A well insulated home can significantly reduce heat loss (or gain), while also lowering your heating bills.

The most energy efficient way to keep your house temperature regulated is through insulation. Adding a layer of material in your walls, floors and ceilings etc works to reduce heat exchange by creating a thermal barrier. In well-insulated homes, less hot air will escape during the colder months, and vice-versa for the summer!

Remember, if you want to build a sustainable home you’ll need to insulate your property well beyond current UK building regulations. An independent sustainability expert can help you determine how best to do this for your home.

Make Insulation part of your design decisions

Remember heat can escape in all directions, so it’s important to cover all bases when insulating your home to cut your heat losses. When building a new home or renovating, you want to try and achieve what’s called a ‘thermal envelope’ – making sure there’s no holes or gaps in your insulation, which could let the hot air out. Be sure to insulate everywhere possible for efficiency and continuity. This includes your roof, walls, floors, around windows and doors, and any attic or loft spaces. Don’t forget to minimise any gaps around pipes etc which go into your home too.

Work with your independent sustainability expert to really scrutinise your design and highlight any areas that need special attention or could cause a problem.

Maximise the Benefits of a well Insulated Home

There are lots of reasons for focusing on boosting your insulation levels – here are just a few.

  • Reduces carbon emissions, minimising your home’s environmental impact
  • Saves you money by lowering your heating bills
  • Improves the comfort of your home, both in the winter and summer months
  • Makes your home a more quiet place by reducing external noise pollution such as traffic
  • Reduces the risk of condensation and mould in your home
  • Future-proofs your home and will improve it’s sale-ability

Talk to an Expert and Consider Your Options carefully

If you’re building a new house or adding a new extension then get an expert to help you determine the best way to boost the insulation in your designs. As we’ve said before, don’t be satisfied with just meeting UK building regulations – now is your best opportunity to make a difference!

If you are renovating your house and it is feeling cold, the likelihood is you are losing a lot of heat through your walls. If your house was built after the 1920’s it’ll probably have cavity walls. This is essentially two walls, with an air gap between them. For this you’ll need an insulation installer to inject insulation material into the cavity. If your property has solid walls, you can do installation externally and cover it with render, cladding or cement.

However it is important to get an independent sustainability expert to look at your home, as if this is done incorrectly it can cause problems. Every property is unique and should be approached individually.

Investigate your options for Insulation Materials

Fibreglass is commonly used throughout the UK as insulation, but it can be less safe to handle, and doesn’t have the same eco friendly benefits as some other materials.

Some of the most sustainable options you can look at include:-

  • Natural fiber insulation materials, including sheep’s wool, hemp or cotton
  • Cellulose which is made from recycled plant materials
  • Spray foam made from soy or vegetable oil rather than petroleum
  • Shredded recycled denim or paper insulation (treated to be fire retardant)

Again, we’d recommend you talk to an expert before making your final decision.

Don’t Forget Your Windows

When you are planning your project you will probably consider a variety of options regarding different types or level of insulation and window specifications. These options can be modeled and quantified by calculating the U-Value of the combination of the materials. This is basically a measure of how well the property can resist heat flow. The lower the U-value, the slower heat is able to transmit through it, and so the better insulated it will be.

To meet building regulations, windows, like the rest of your property should meet a U-Value. Windows can often form quite a large percentage of your building envelope – especially if you’re installing bi-fold doors or large picture windows. It’s therefore worth getting an independent energy expert to help you understand the choices you have and inform your decision making process. Don’t rely on the glazing salesperson to advise you on the best course of action. Get an independent professional to help you calculate and understand the effect double or triple glazing can have on your home. Windows are a huge investment and it makes sense really understand your options and balance the cost of the initial installation with the reduction you’ll see in your running costs and fuel bills.

Consider the Window Frame Materials

While the U Value of your windows is important, so is the way they are manufactured. It’s also relevant to think about what the best option is for sustainability with both the glazing and the window frames.

  • UPVC window frames have fallen out of favour recently, but are extremely energy efficient. However as a material they are not sustainable. They use a lot of energy in their manufacture and aren’t made from renewable materials. They are rarely recycled, and even if they are, the energy used to recycle them is very high.
  • Wooden window frames have a good U value and have a much smaller environmental impact, as they come from renewable sources. They also need much less energy in their manufacture and are easily repaired and recycled. However the you will need to budget for painting or treating them regularly to prevent them rotting.
  • Aluminium or steel frames, are very fashionable at the moment. They are long lasting, and can be recycled, but are less energy efficient.
  • Composite frames can be a good compromise. These are made of multiple materials such as wood and aluminium pressed together under high temperatures.

Installation is key – Remember to check for air-leakage

It’s no good having lots of insulation, or high specification triple glazed windows if your house is full of gaps letting all the cold air in and the hot air out! You want to make sure your home is as air-tight as possible. This will prevent air leakage through the windows, doors, or even walls, which could in turn leads to problems such as mould or rotting wood.

Foam sealants and special tapes can be useful here to help prevent air from leaking, but it’s best to get a professional to advise and perhaps get an air tightness assessment before sealing up any gaps you think could be causing a problem.

Make your Roof Green Too

Insulating your loft or roof space is important, but you can do even more to your roof to make your home sustainable.

PV arrays are a brilliant way of boosting the sustainability of your home. They’re simple and cost effective to install (and maintain) and are a great way to generate your own electricity. Your roof orientation etc will need to be checked for suitability by an independent expert, but they pay back relatively quickly and are certainly always worth considering.

You can also help the environment and improve the appearance of your home by adding a green roof. You might think that they’re too difficult to set up and keep going, but this is not the case. The plants are typically low growing, and don’t require a lot of maintenance. They’re even drought tolerant, so you don’t need to be climbing up to your roof everyday with a watering can! Green roofs can be an attractive way to make your house more sustainable, but do check that the additional weight of the green roof is not a problem structurally with your architect or structural engineer.

Don’t Forget About Water

Water is a valuable resource and if you want to make your home more sustainable its use should be minimised where possible. Grey water is the wastewater from baths, showers, sink and dishwashers and washing machines. This wastewater can be recycled and re-used to flush toilets, water plants or wash clothes. There are many systems on the market which treat the water via filtration and/or chemical means and then enable its reuse.

Similarly, each year thousands of litres of rainwater fall from our roofs and go via our drainpipes into the sewage system. Installing a simple water butt into a downpipe can catch and store rainwater to be used in periods of drought to water plants etc. More elaborate systems can also be considered to store, treat and enable you to reuse the water in the home.

Find Out More

We do hope we’ve given you some new ideas for how you can make your project more sustainable. If you’d like to understand more about how our heating and sustainability experts can help you make the best decisions we’d love to hear from you.

Simply call 01923 896550, email or complete a contact form.

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CLPM Project Managers cover London, Bedfordshire, Berkshire, Buckinghamshire, Gloucestershire, Hampshire, Hertfordshire, Oxfordshire, Surrey, and West Sussex. Energy Consultancy and Cost Advice services available across the UK.
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