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 compromise
this 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 uvalue 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 rehanging
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
Bonded polystyrene bead u-value 0.31
U-value improvement 68%
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), uvalue 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
90
80
Maximum Daily Relative Humidity [%]
70
60
50mm into Brick/Close Wall
50
Interface Close brick
wall/Insulation
50mm into Stone/Exterior Wall
40
30
Interface Exterior Wall
Stone/Insulation
Room (RHmax)
20
10
0
May-2010 Jun-2010 Aug-2010 Sep-2010 Nov-2010 Jan-2011 Feb-2011
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, uvalue 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
moses.jenkins@scotland.gsi.gov.uk
Which one has the best chance of
still being useful in 100 years?