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Improving Energy Efficiency in Traditional Buildings
Moses Jenkins
Technical Conservation Group
Contents
• Traditionally constructed buildings
• Building elements: improvement options– Windows– Walls– Roofs– Floors– Doors
Vapour movement in a traditionally built home.
We can improve efficiency, but must be careful not to compromisethis dynamic.
Typical energy efficiency upgrade using expanded phenolic foam
Traditional passive ventilation systems
If we get it wrong..
Windows
Draught Stripping
Existing options – shutters & blinds – gave significant improvements u-
value 1.8
Secondary glazing
Secondary glazing : U Value 1.7
secondary glazing manufactured by a joiner
new sealed units within existing sashes, u-value 1.3
A new check is cut and the unit puttied in place
Upgraded sashes awaiting re-hanging
Walls
Historic Scotland research has examined 3 approaches to insulating mass masonry walls:
•Putting insulation behind existing wall lining
•Applying material directly to the masonry “on the hard”
•Framing out and putting material between the timber
U-value improvement 68%
Bonded polystyrene bead u-value 0.31
30mm Calcium silicate board applied directly to mass masonry
Preparation for application of board (left) and the build up of the board and finishing layers (right), u-
value improvement from 2.1 to 1
10mm Aerogel blanket fixed directly to mass masonry
Aerogel blanket particularly useful on curved walls, u-value improved from 1.3 to 0.6
Where previous linings have been lost or are irreparable more substantial
interventions can be made
Hemp board – u-value 0.21
Thermal improvement 78%
80mm Wood fibre board u value 0.19
Thermal improvement 81%
Clay board (right) ready for application of clay plaster (left)
100mm cellulose fibre blown on the hard – U value 0.28
Thermal improvement 71%
Aerogel insulated board – 50mm u value 0.31
Thermal improvement 65%
An important element of the testing program is monitoring of moisture build up
Moisture monitoring following the application of the insulation at Sword Street
0
10
20
30
40
50
60
70
80
90
May-2010 Jun-2010 Aug-2010 Sep-2010 Nov-2010 Jan-2011 Feb-2011
Max
imum
Dai
ly R
elati
ve H
umid
ity
[%]
50mm into Brick/Close Wall
Interface Close brickwall/Insulation
50mm into Stone/Exterior Wall
Interface Exterior WallStone/Insulation
Room (RHmax)
External Insulation
Maybe not here…
But what about here?
Wood fibre insulation, Glasgow
Negative visual impact of external insulation
Floors
Is it worth lifting this?
Sheep’s wool pinned to under floor joists
Hemp board between joists held in place with timber runners, u-value
improvement 2.4 to 0.7
Breathable?
Stone floors – can this be improved?
Laying the insulated floor as a homogenous layer
Concrete floors can be lifted and insulated lime concrete floor laid in its place
Lime concrete layer being mixed, laid and flags laid on top
Aerogel board placed over concrete floor, u-value improvement 3.9 to 0.8
Lofts and roof spaces
Should be 275mm thick whatever material used
Vapour permeable options most appropriate such as sheep’s wool or wood fibre board
Sheep’s wool between joists, u-value improvement 1.5 to 0.3
(wood fibre board u-value 0.2)
Insulating behind existing roof linings in inhabited loft space, u-value
improvement 1.6 to 0.8
Blowing bonded bead into a mansard dormer cheek insulation behind the plasterboard
Insulating between rafters using hemp / wool material
Doors
Door panels can be insulated to reduce heat loss, u-value improvement 3.9 to 0.8
Conclusion
• Vapour permeability and ventilation should be maintained throughout any energy upgrade work
• All elements of traditionally constructed buildings can be made more thermally efficient by the use of a range of materials and techniques
• It is vital that this work is carried out sensitively to both the aesthetic and performance of the building and ventilation vital to
More details of all research available at Historic Scotland
website:
www.historic-scotland.gov.uk/technicalpapers
I can be contacted at [email protected]
Which one has the best chance of still being useful in 100 years?
