Downie's Cottage

Hill Street

AB35 5XX

Braemar, United Kingdom

Architect

Erdal Architects
12g Timber Bush, Edinburgh EH6 6QH
richard@erdal.co.uk
00 44 131 554 6725

Contact Details

Roger Curtis
Historic Environment Scotland
roger.curtis@hes.scot
00 44 1316688621

Other Information

HES Refurbishment Case Study

Related publications
Historic Environment Scotland Refurbishment Case Study
This project was the refurbishment of an early 19th C croft house located near Braemar in the Cairngorms National Park. It is a rare survivor of a vernacular building type once common in Scotland and is Category 'A' Listed. Works included insulation to walls and floor, upgrades of the windows and the installation of a ground source heat pump.
Energy performance Primary Energy:
412 kWh/m2.y

Climate Zone CFb

Altitude 1500 m a.s.l.

HDD 2912

CDD 83

Protection level Listed

Conservation Area:
Yes

Level of Protection:
Scottish Category 'A' Listed - denoting national importance

Building age 1800-1849

Year of last renovation:
0

Year of previous renovation:
70

Building use Residential (rural)

Building occupancy:
Discontinuous occupancy (i.e. holiday home)

Number of occupants/users:
2

Building area Net floor area [m²]: 20,0

Building typology:
Detached house

Number of floors:
1

Basement yes/no:
No

Number of heated floors:
1

Gross floor area [m²]:
20,0

Volume [m³]:
40,0

NFA calculation method:
Useful area (ro)

Construction type
Stone masonry wall

External finish:
Rendered

Internal finish:
Plastered (on hard)

Roof type:
Pitched roof

+ MORE - LESS
Before work started; HES image
Before work started; HES image
Former byre now garage and plant room; HES image
Former byre now garage and plant room; HES image
View of the cottage before renovation.
View of the cottage before renovation.

RENOVATION PROCESS

Architecture

BUILDING DESCRIPTION

Probably early to mid 19th century. 3-bay, single-storey and attic, rectangular-plan crofting cottage situated on high ground overlooking Braemar village. Rubble with lime render and pointing. Corrugated-iron roof covering heather thatch. N ELEVATION: Timber lean-to porch to centre, breaking eaves with timber door to left side; windows flanking. Smaller single windows to S and W elevations. INTERIOR: traditional plan arrangement comprising two principal rooms to E and W with central core of box-beds and stair to roofspace. Room to E: stone flags to floor; raised hearth with granite shelf to right and cast-iron fireback with rose motif; timber 'hanging-lum' above with shelf to base of cowel; small wall niche to right. 2-leaf panelled timber doors to cupboards and box-bed. Room to W: remnants of fireplace and box-beds. Further box-bed behind staircase. Roofspace and stair lined with timber and 19th and 20th century newpaper and magazine print; 2 further box-beds to W end of roofspace. 9-pane glazing to timber sash and case windows. Coped and rendered ridge stacks located toward gable ends.
Urban context
The cottage is in a rural environment

HERITAGE SIGNIFICANCE

ELEMENTS WORTHY OF PRESERVATION
The main features for preservation were the hanging lumb in the east gable, and the box beds in the 2 ground floor rooms.
Heritage Value Assesment
Downey's Cottage is an exceptionally rare and important survival of the open hearth tradition of vernacular building in the North East of Scotland. This simple 3-bay cottage is remakable for its largely intact interior with traditional plan arrangement with rooms to E and W and a central core comprising box-beds and a stair to the roofspace. Key points of interest include the raised stone hearth beneath a timber 'hanging-lum' chimney, and 19th and 20th century printed newspaper lining and heather thatch beneath the corrugated-iron roof covering.
Heritage Assessment Files
A late 19th century watercolour showing the porch of Downie`s Cottage (painted by Miles Birket Foster)
A late 19th century watercolour showing the porch of Downie`s Cottage (painted by Miles Birket Foster)
The cottage viewed from the north, showing the vertically laid timber plank roof covering protecting the thatch.
The cottage viewed from the north, showing the vertically laid timber plank roof covering protecting the thatch.
The cottage in the middle of the 19th century, viewed from the north west.
The cottage in the middle of the 19th century, viewed from the north west.

State of repair

Conditions of the envelope
The cottage had been empty since 1933, and was in a poor condition on the ground floor. The West gable was fragile and parts of the south wall had collapsed. The upper floor and roof were in good condition.
Description of pre-intervention building services
No services present. Heating by 2 open fires in each gable.

Aim of retrofit

Renovation
The aim of the project was to bring back the building back into residential use (as a holiday property) but retain its historic character and finishes, as well as ensuring that the property fulfilled modern expectations of comfort at this exposed site. To ensure technical compatibility with the existing fabric traditional materials and techniques were used for the fabric repairs.
Lessons learned
The lowering of the floor level to fit in the lime concrete floor took longer than expected, and obliged some improvement to the foundations.
Stakeholders Involvement
Public sector
Historic Environment Scotland (HES)
Longmore House, Salisbury Place, Edinburgh, EH9 1SH
Private Sector
Private Client
Braemar, Aberdeenshire
Architect
Erdal Architects
12g Timber Bush, Edinburgh EH6 6QH
richard@erdal.co.uk
Tel.00 44 131 554 6725
Conservation Consultant
Sonya Linskaill
Dunellan, Strathyre FK18 8NA
Tools used
Energy calculation The design team used Energy Plus software for the building warrant
Hygrothermal assessment A condensation risk assessment was done for the wall insulation
Life Cycle Analysis (LCA) Not done formally, although the materials used were selected for a 50 year + lifespan.
Other An infra red survey was conducted

RETROFIT SOLUTIONS

External Walls

Solid masonry; lime bonded 700mm thick.

Solid masonry; lime bonded 700mm thick.

Insulated lime plaster was applied to the inside face of the wall, 60mm thick.

The material chosen was a lime plaster, similar in properties (vapor permeable and capillary active) to the existing plaster, which had largely fallen off.

U-value (pre-intervention) [W/m2K]: 1,765 W/m²K U-value (post-intervention) [W/m2K]: 1,226 W/m²K
More Details
Original wall build-up
Stone - Drybonded wall with rough-hewn stones. May have had clay or earth fill in the wall core:
700 mm
Plaster - An internal lime plaster layer of varying thickness:
30 mm
Retrofitted wall build-up
Stone - As original:
700mm
Plaster - Application of 2x30 mm of insulated lime plaster:
60 mm


Windows

Timber Sash and Case (Vertical sliding)

Timber Sash and Case (Vertical sliding)

Yes, but not for thermal reasons - fire regulations obliged the reworking of the second window as an escape window.

The windows were removed and cleaned down back in the workshop. Due to their mall size thermal improvements were not deemed to have been effective

Existing window U-value Glass [W/m2K]: 5,0 New window U-value Glass[W/m2K]: 5,0 Existing window U-value Frame [W/m2K]: 1,4 New window U-value Frame [W/m2K]: 1,4
More Details
Existing window type Sash window
Existing glazing type Single
Existing shading type NA
Approximate installation year 1910
New window type Sash window
New glazing type Single
New shading type NA
New window solar factor g [-] 0,6

Other interventions

ROOF

GROUND FLOOR

ROOF

The upper floor was not going to be used, so a thermal break of woodfibre insulation was introduced on the first floor to make a separation.

Yes, wood fiber is vapor and capillary active. In this case the wood fiber was laid on the floor in the attic, and can easily be removed.

U-value (pre-intervention) [W/m2K] 0.9 U-value (post-intervention) [W/m2K] 0.9
More Details
Original roof build-up
Metal sheets - Corrugated metal sheet covering a heather thatch:
300 mm
Other - Softwood boarding:
7 mm
Retrofitted roof build-up
Other - Original roof covering was retained:
2 mm
Other - Softwood boarding:
7 mm
GROUND FLOOR

The existing flagstones were removed and the floor was excavated down to a depth of 400mm below the floor level, in order to increase the room height and to fit in the insulation. An insulated lime concrete floor was laid in the excavated space.

This is an established conservation measure as an alternative to a concrete floor that allows continued water vapor movement through the fabric.

U-value (pre-intervention) [W/m2K] 4.5 U-value (post-intervention) [W/m2K] 0.28
More Details
Original groundfloor build-up
Other - Flagstones bedded on earth.:
300 mm
Other - Stone slabs:
50 mm
Retrofitted groundfloor build-up
Other - The original flagstone floor was only present in the kitchen and the hallway, whilst the remainder of the ground floor had a timber floor.:
10 mm
Other - Relayed flagstones:
100 mm

HVAC

HEATING

DOMESTIC HOT WATER

HEATING

There were only two open fires in the building, one was changed to a wood burning stove, the other was left but the flue closed off. The heating system was a ground source heat pump.

The solution is conservation compatible, as the ground floor was being lifted as part of the refurbishment work anyway. Although, o get the heating loop in the building, we had to make the hole in the east wall.

More Details
New primary heating system New secondary heating system
New system type Heat pump Stove
Fuel Electricity Wood
Distribuition system Radiating floor Air
Nominal power 53 kW 20 kW
DOMESTIC HOT WATER

A new hot water cylinder was installed in the byre, heated by the loop of an immersion heater.

No effect on the fabric, and located in a discrete cupboard.

More Details
New DHW system
Type Immersion heater
Hot_water_tank Yes
With heat recovery No

Energy Efficiency

Energy Performance
Energy performance certificate: Current energy efficiency rating is band D SAP value 61, while current Environmental Impact Rating is also band D (65).
Voluntary certificates: No
Energy Use
Heating
Primary Energy 412 kWh/m2.y

Primary Energy
Consumption_estimation_Calculation_method: Steady state simulation (e.g. EPC, PHPP)
Documents:
EPC - Tomintoul Croft Braemar.pdf
Downie's cottage EPC, January 2016

Consumption_estimation_After: 412 kWh/m2.y

Internal Climate

Temperature

The cottage is kept at 16 degrees, with additional local heat from the wood burning stove during periods of occupation.

Indoor Air Quality

This has not been formally assessed, but appears to be satisfactory.

Daylight

Provision of natural light is modest due to only two windows in the North elevation, and on quarter light on the South elevation.

Artifact Conservation

The steady temperature has suited the wallpaper and paneling very well, no damage or distortion observed.

Costs

Financial Aspects

Internal and external wall insulation has improved the environmental and energy efficiency rating of the building. It has also increased the savings of the household.

Investment Costs

Cost of energy related interventions:
£14,565.79 (total)
Amount includes: The cost includes boiler and other related installations (pipes, insulation, ducts...), labor and commissioning.
Running Costs
Total annual energy cost
940£ (total)

Lifecycle cost
No

Environment

Greenhouse Gas Emissions
Methodology_used: Covered in simplified form by the EPC. The calculated emissions for the cottage were 70 kg CO2/m²/yr.
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