8 St. James Street

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Opening Times

Saturday 15th October

Saturday 22nd October


Address; 8 St. James St, Lewes, BN7 1HR
Owner: Neil Williams
Type: end of terrace
Built: 1789
Beds: 2
Walls: brick, (some half brick thick)
Area: 90m2
Residents: 1 adult

Eco Features

Condensing boiler
Flat roof insulation
Solid wall insulation(internal)
Woodburning stove
Secondary double glazing (magnetic)
Underfloor insulation
LED lighting
Low energy appliances


In August 2012 Neil bought this house and just before moving in, the attic was stripped and solid wall insulation was fitted internally in the two reception rooms.
Subsequently, the attic was relined with high levels of insulation, to put a snug cap on the house.

A woodburning stove was added to the sitting room, with cellar insulation underneath.

All lights were replaced with LEDs and new appliances were A to A+++. Cheap and near invisible magnetic secondary double glazing has been fitted to four windows.
In 2013 the ceiling of the rear extension was stripped to fit much better roof insulation. In 2014 raised beds were added to the garden for vegetable production, as well as espalier fruit trees.

Developments in 2015/6 - more solid wall insulation for hall wall and back bedroom - cellar stairs insulated - new timber double glazed sash window - new highly insulated timber framed extension - more magnetic secondary DG.

Energy use is now around 40% of an average house which is not bad for a leaky Georgian building. When PV is fitted, carbon emissions will be down by 90% and could reach reach zero carbon.

Refurbishment has cost £7500 (excluding the extension), of which £1500 was for essential roof strengthening. Net 'eco' expenditure is therefore £6000, most of which was DIY with friends.

Energy efficiency measures

Heating and hot water

The house already had a modern condensing boiler supplying water to a well insulated pressurised cylinder.

A woodburning stove in the lounge helps cut down the gas use and heat percolates upwards to the bedrooms.

In autum 2013 glazed doors were fitted to both the back sitting room and the front room. Previously these had been open plan and heat had escaped. Fitting these doors has had a big effect in keeping the living areas snug, without heat continuously being lost to hall and stairs. Because the doors are glazed, light is still able to spread to the interior.



The lath and plaster ceiling was stripped out in the loft mainly to raise the head height from a tight 1.95m to over 2.4m. In the process it was apparent there was no insulation, so 50mm Celotex PIR foam boards were slotted between the rafters, taking care to leave a ventilation space of 50mm above, to allow the roof to breathe and avoid condensation. All joints were taped to avoid infiltrating air coming from behind and undermining insulation. The flank wall was very uneven and was stripped back to brickwork, levelled with hardwall plaster and overboarded with laminated plasterboard, formed of 9.5mm board bonded to 19.5mm foam insulation. The chimney breast and party wall were also clad in laminated board, which was carried up over the sloping ceiling and eaves walls to improve overall insulation and limit cold bridging via the rafters. In the eaves themselves, Celotex insulation was carried down between the rafters and rockwool was placed between the ceiling joists, which were overboarded to create storage. The eaves joint needed careful detailing to prevent draughts and divert ventilation above the insulation. The aluminium double glazing in the attic was retained, even though not to current standards, as it is still pretty effective and in good condition.

Front sitting room

Slim laminated solid wall insulation (28mm overall thickness) was fitted to the inside surface of external walls, so as to encroach as little as possible on already limited internal space. This cut heat loss from those walls by around 70%. In order to fit the insulation it was necessary to remove skirting and architraves, undo light fittings, switches and sockets and take down the radiator. This sounds complicated, but it happened very quickly and easily. Before the board went up on the walls, the position of those fittings was recorded using the cunning method illustrated on YouTube, so that they could be easily reinstated on the wall surface. The only slight complication involved creating slightly deeper reveals around the windows and doors by fixing battens around the perimeter, to which the conserved architraves could be refixed.

One big cost bonus of using laminated board with tapered edges is that joints can be taped, filled and sanded ready for decoration without the need for plastering the whole wall. A very sustainable measure too, avoiding high embodied energy plaster.

Below the sitting room there is a cellar and it was very easy to fit 170mm rockwool loft insulation between the joists from below to insulate the floor. The front window was insulated using magnetic secondary double glazing which is virtually invisible and only costs from around £50 to £150 depending on size. This cuts draughts and makes the small room far more usable and comfortable. The acrylic came from Brighton and Hove Plastics in Portslade who are very reasonable and cut to fit exactly while you wait. They also stock some Magnetic glazing supplies, but the best source seems to be the internet (see information sheet referred to at the end).

Garden room

The side walls of this extension are solid brickwork and lost heat like a sieve in winter. These two walls were overboarded with Celotex PL4000 laminated board (37.5mm overall), which has cut heat loss by 70%, without impacting on space. This was fixed using Dow InstStik adhesive foam and secured using Insofast drywall fixings. Because of the clearness of the walls this was done by two people in half a day, with a minimum of fuss. There was a further day and a half of filling, decorating and reinstating skirting for one person.

The timber ceiling was believed to be insulated with rockwool between the joists, but during the winter it was easy to observe that frost and snow quickly melted on the roof to reveal the pattern of ceiling joists, indicating no insulation at all. This was resolved in autumn 2013 by stripping the plasterboard ceiling, inserting 100mm Celotex PIR insulation between the joists and replasterboarding. The whole job took two days with a friend, inculding decorating and has had a huge impact. The room stays warmer in winter and is also much cooler in summer as sunshine on the flat roof used to radiate straight through to the ceiling. On sunny days the ceiling temperature used to reach 30 degrees plus!

The garden doors are fairly recent with timber framing and double glazing. However the single glazed window now has a magnetic secondary double glazing panel, which is virtually invisible but cuts heat loss by half, for a cost of about £40 all in.

One of the most cost effective measures was to insert a cardboard panel, covered in aluminium foil, behind the radiator. This has the immediate effect of raising the temperature in the room by 1.5/2oC, by preventing the radiator wasting heat in warming up the solid brick wall behind.

Renewables and Low carbon technology

With only one person living in the house hot water use is pretty low, which makes it hard to justify solar thermal water heating, although technically feasible.

A better investment would be solar PV on the roof of the extension, where any surplus electricity could be exported for use by my neighbours. Quotes have been obtained showing that 4 kW could be fitted easily, but installation has been delayed due to the construction of a first floor timber extension. When this has been finished the space available will be different and new quotes will need to be obtained.


Low energy LED lighting has been installed throughout, cutting the lighting load to 10/20% of old halogen and incandescent lamps. With all lights in the house on, the total load is only about 100W, i.e. the same as one old light bulb! LEDs cost less than £10, look good and pay for themselves from savings in 1-2 years. One of the cheapest and most effective measures I made. (see information sheet at end for technical and supplier information)

The low energy fridge freezer and washing machine are A+++ or as near as possible.

Other sustainable Measures

The end of the garden has been cleared to create space for raised beds for vegetable growing. In spring 2014, fan trained fruit bushes and trees were planted along the south facing fence to both maximise space and grow more produce.


Laminated plasterboard Insulation: Celotex PL4000. http://www.celotex.co.uk/products/pl4000
Woodburning stove: David Sibley, Energy Wake Up Ltd. http://www.energywakeup.co.uk/
Magnetic secondary double glazing: see link for information and local suppliers http://transitiontownlewes.org/magnetic_secondary_double_glazing.html
LED lighting: see link for local information and suppliers http://transitiontownlewes.org/switching_to_led_lighting.html


8 St. James Street
8 St. James Street
8 St. James Street
8 St. James Street
8 St. James Street