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

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May-2010 Jun-2010 Aug-2010 Sep-2010 Nov-2010 Jan-2011 Feb-2011

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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 moses.jenkins@scotland.gsi.gov.uk

Which one has the best chance of still being useful in 100 years?