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The first and most cost effective change you can make is generally to reduce the energy you are wasting or might waste in your new build because of the building fabric itself.
Insulation.
Uninsulated roofs are a major source of heat loss and many people have some insulation in their lofts and roof-spaces. For the majority of existing properties the amount of that insulation is far too little. The amount required also varies depending on the type of insulation in use and where it is put (on the slopes or on the flat).
There is a massive range of alternative insulation types available. Many are natural and so are better for the environment in one sense, but may not be as effective and so more is needed to get the same level of insulation.
Choices need to be made based on whether the insulation needs to be porous or even to absorb moisture, whether you want a natural product and how much space you have available and what your budget will afford. The options we can guide you through include poly-isocyanurate, (or Cellotex type products), sheeps wool, wood pulp, hemp, recycled fibres, fibreglass...
The walls and floors also need insulating if at all possible. In more modern constructions there is usually a cavity, which if not already insulated can be pump filled with poly-isocyanurate or polystyrene balls. Alternatively and where the walls are solid then walls can be lined on inside or out with insulating material. Again that can be porous or non-porous and for solid masonry porous is preferable.
Obviously if the insulation is to go on the outside it needs to be weatherproofed, but the advantage would be that inside space would not be reduced and the masonry of the walls would become like a huge storage heater retaining heat on the inside for longer.
Call us to discuss the huge range of insulation types we can provide and install. We can give you the relative benefits and the costs in a nutshell.
Eliminating Cold-bridges:
It’s vital to think about these areas where the heat can be transferred most easily through the fabric of the building from inside to outside. This is especially important in designing new-builds or extensions so the issue can be avoided at the outset.
When improving insulation, the same thinking of identifying and addressing cold-spots can be applied to ensure that you do as much as is feasible to reduce the heat-loss in those areas.
Insulated building blocks and materials:
There are a range of building materials we can use which inherently possess isolative properties.
From our work in historic buildings which require porous/breathable materials to avoid damp, we are familiar with using recycled foamed glass aggregates and LECA (lightweight expanded clay aggregate) or hemp to create insulated floors or within lime concrete for walls or floors.
Hemp-lime concrete blocks can be used in much the same way as any other concrete block. Recycled foamed glass blocks can also be used especially at low level, potentially damp areas.
Hemp and lime mixtures can alternatively be sprayed into a shuttered timber framed structure to form insulated walls in situ.
New alternatives are interlocking preformed blocks (such as Durisol) made from woodcrete which can be quickly formed into a wall and then part-filled with lime concrete and partly insulated to create a high performance insulated, breathable wall.
These are similar to the interlocking polystyrene blocks which have concrete poured into the whole of the cavity to create a composite wall. This would form a non-porous wall and has higher levels of embedded energy in the materials.
We have suppliers of all this range of products, advise on their usage and can adapt them to your requirements.
Cob and rammed-earth: Structures which use cob and rammed earth containing straw or hemp or similar would certainly have some great characteristics of thermal mass and some insulation. However at this time no one has done the experiments to prove the case. Corbel can create structures in cob by any of the usual methods ( see other pages of site)
Straw-bale buildings: Straw and similar materials have been used as effective insulation for centuries. In recent times we have standardised excellent building techniques for using baled-up straw for building highly durable, breathable, but fantastically well insulated buildings for commercial and domestic use. Far from being a material for hippies or cranks, straw-bale could now take it’s place with other insulated building materials within thermally efficient new builds or extensions.
Corbel have developed relationships with pioneering companies in this field to understand the methods and materials and be able to offer this as an option.
What’s also vital and set us aside from most is that from our years of conservation work, we fully understand the use of lime products which are essential in complementing many of these other building techniques.
Draught reduction:
Only a few years ago our building regulations insisted on a minimum amount of ventilation within every building. Current thinking is to reduce the ventilation and the regulations now state maximum rather than minimum amounts of ventilation. This presents a problem as many buildings were built with the earlier standard in mind. Especially in historic buildings it may be detrimental to reduce ventilation too far. It’s about getting the balance right.
In all buildings there’s probably no major issue with sympathetically introducing draught-proofing measures which eliminate the gales blowing under doors and around loose fitting windows.
It will be necessary to maintain airflow around timbers under floors and in roof spaces, but there’s no disadvantage to stopping that airflow creating cold draughts into the living space and so making the heating turn on.
Corbel can provide a range of services to draught proof. This includes everything from filling the gaps between floor-boards, cracks in plasterwork, gaps around loft-hatches, adjusting doors, fitting brush-strips, providing fixed or removable closures for chimneys and so on. However many draughts come from around windows which are dealt with in the next section.
Windows and glazing:
This is another significant area of heat loss in most buildings.
Double glazing; is the obvious way to improve how much heat is lost through the glazed areas and many people have already gone that far.
The principle is that a single thin glass conducts heat very easily and so gets almost as cold (or hot) as the outside world. That cold surface can cool down the room air as it flows past it. So the second piece of glass on the inside of the double glazing prevents the air flowing directly over the very cold outer glass and the gas in between the two panes of glass can’t transfer the heat or cold very easily because there’s not much air movement.
Triple glazing; adding a third glazing panel makes it work even better, but requires completely new window frames to be fitted.
Low-e glass
To improve the existing double glazing further, it is possible to upgrade by replacing the glazed units with ones using a low emissivity glass. It is claimed that this relatively recent advancement which has an invisible metal coating makes the glass reflect the maximum amount of heat back into the room, but still transmit the maximum possible light and heat from the sun.
Secondary glazing: In buildings where double glazing is not permitted or desired, the alternatives are to add secondary glazing panels. Sometimes these are added across the whole of the inside of the window, but that can be cumbersome as the whole sheet needs to be removed or swung open to open the windows. (See note below on draught proofing benefits)
A system we tend to prefer to use is to add discrete panels to the inner face of each pane of the window.
The secondary glazing can also be made in low emissivity glass as above.
Slim -line double glazing: In recent times some listed buildings have been allowed to have double glazing fitted using a special thin-section glazing unit, which may be acceptable if shown to give an appropriate size of glazing-bar and overall appearance of the window.
Window Shutters: These were traditionally used to conserve heat within rooms at night and work really well. Some buildings still have the shutters in the window reveals or have the boxes into which they folded. Our joiners can either create new shutters or reinstate or refurbish shutters, custom made to your windows.
Draught-proofing windows: Whilst refurbishing windows in existing buildings, we often improve the draught-proofing by fitting a clever system of brush strips carried in a plastic channel which is let into hidden faces of the window timbers. It is possible to do this really well on sash windows which need to have gaps to function, but that leads to draughts and rattling. The brush-strips take up the gaps and are available in a range of sizes to fit different gaps.
Secondary glazing which fits over the whole window as above also generally draught proofs at the same time. |