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The Latest Contempory Designs we have Produced for our Clients have lots of Glass in the Roof and Walls.

For this type of Design, whether it be a house extension, or a large new build house, the loss of heat and energy through the external envelope must be controlled at the earliest stages.
At Homeplan Designs, even at the preliminary planning stages we are assessing the costs of the energy bills to heat such a structure.
Our 3D Modelling design software allows us to assess the impact of any changes in the fabric of the structure. From that extra large window, or ‘curtain wall’ as we call it, to the Orangery Style roof. We are able to make sure that the building work will comply with the requirements of the Building Regulations.

Our recent clients have seen the benefit of this for their large Orangery extensions.
When an existing room is extended using this type of glazed structure there is a big difference in energy heat loss between the new and older parts of the building.
This is because the older part of the building will have been built under previous Building Regs Rules, allowing a greater heatloss through the walls,windows floor and roof.
It is a known fact that an extension to a room will ‘share’ the heatloss of the original room.
So if there is going to be a large amount of glass in the extension, either in windows or roof glazing, or both, then any new windows will need to be more efficient than what is allowed as a minimum U value of 1.8 under the building regs for new building work.
In fact the whole of the new building will need to be uprated with better insulation values to walls, windows, roof and floor, so as to compensate as an offset for the whole buildings heatloss and efficiency.
The way it is calculated is that a heatloss assessment of the same size of extension using the maximum allowed U values under the building regs for what is termed as the elemental parts of the new notional extension structure ie the walls O.28W/MsqK, roof O.18W/MsqK, floor O.22W/MsqK and windows 1.8W/MsqK. the windows should have an area of no more than 25% of the wall area.
This notional target heatloss figure is what we need to equal or better with the heatloss through the elements of the extension. ie by upgrading the U values with extra or better insulation and more efficient glass.
However, sometimes it may not be possible to acheive the required value to acheive a PASS under the building regs using this method.
If this is the case then a different method has to be used. This by taking the combined existing and proposed parts of the building and assessing a whole manner of ways the building would lose energy/heat ie the amount/thickness of existing roof insulation, the efficiency of the boiler
type of existing wall insulation and the type of glazing, as well as number of mech vents, chimneys, radiator valves etc etc. The orientation of the building is also part of the equation so as to assess heat gain from the sun etc etc.
This assessment report can easily run to 11 or 12 A4 pages. What we are wanting to prove is that energy/heatloss of the designed extension plus the existing structure is less than that of the same calculation using the afore mentioned notional building.
Note that this figure can be tweaked to give the required PASS by adjusting various elements within the proposed extension model structure or by adding extra insulation to the existing house roof or even installing a new efficient boiler.
As you can see a modern fully glazed contemporary extension to an existing building can be quite tricky, but with the design software that Homeplan Designs uses it allows us to make the project meet the requirements of the building regs and even future proof it.
Remember that every year extra energy requirements are being brought into the building regs so as to reduce our UK buildings carbon footprint. Remember, if you are using less energy, then your fuel bills will be much lower. Even to the point that your building can become Carbon Neutral, but thats another story..
Contact Chris at Homeplan Designs to discuss your new extension requirements
Tel 01253 737724
email chris@homeplan-designs.com

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