The works

External works, ground levels, surface drainage

Moisture-related maintenance work

✓

Re-pointing of mortar joints

Re-rendering or plastering of walls

Internal wall insulation

✓

External wall insulation

✓

Cavity wall insulation

✓

Fit flue damper or flue balloon

Block flues

✓

Window maintenance

Secondary glazing

Retrofit double glazing to external windows

Windows & external door replacement

✓

Draughtproofing

High level of airtightness

✓

Internal redecoration

✓

Insulation of suspended timber ground floor

Replacement insulated solid concrete floor

✓

Maintenance work to roof and drainage

Roof insulation on flat ceiling

✓

Roof insulation on pitched ceiling

Re-plumbing

✓

New room heaters

Heating system replacement

✓

Heating controls upgrade

Domestic hot water storage upgrade

✓

Solar hot water

✓

Re-wiring

✓

Change to 100% low energy lighting

Standalone extract ventilation

Whole house demand control mechanical extract ventilation

✓

Mechanical ventilation with heat recovery

Replacement of timber floors

The existing timber floors were removed and replaced with solid concrete floors incorporating 150mm of underfloor insulation. The decision to replace the timber floors was informed by a client requirement to introduce underfloor heating throughout the ground floor of the house.

Medium - High

Original floor construction was removed

Cavity wall insulation

The external walls were discovered unexpectedly to be of cavity wall construction. The 75mm cavity was filled with platinum bead insulation

None

Internal wall insulation

A variety of supplementary insulation measures were undertaken in response to different conditions:

The original front brick façade was retained and internal thermal lining was employed. 30mm composite plasterboard/PIR board was applied in the entrance hall where the existing stairs and small first floor wet rooms restricted the depth of internal lining possible. Where space restrictions did not apply, 90mm of cellulose insulation between timber studs was applied to the front dining room and first floor bedroom walls with cornices reproduced over the thermal lining.

To reduce the amount of water wicked into the brick wall from driving rain, the outside face of the brick was treated with a highly breathable silane impregnation (the drier old walls are, the safer an internal wall insulation retrofit is likely to be).

Low

No significant internal wall features existed or were altered.

External wall insulation

The existing side gable walls (which were originally rendered) were insulated with 150mm EPS external wall insulation. Where thermal bridges between internal and external wall insulation occurred, the internal insulation was generally returned along internal walls to mitigate the problem.

Medium

The EWI to the gables is visible from the road

Attic Insulation

The existing attic was insulated with 300mm of blown cellulose insulation. Unlike fibre attic insulation, this material has greater thermal mass which helps to moderate winter heat losses and summertime heat gains to roof spaces. As the material was pumped into the attic space, ventilation at eaves level was maintained by means of a proprietary tray system.

None

All original fabric was retained

Heating system replacement

A fully zoned gas fired heating and hot water delivery system was installed to serve the relatively low heat demand of the completed building.

Low

Existing service routes were used insofar as possible

Solar thermal

A solar thermal panel was fitted to the rear south facing roof slope to partly supply domestic hot water heating requirements.

Low

Rear elevation has been substantially modified as part of the extension project

Airtightness detailing

An airtightness level of 2.5 m3/hr/m2 per hour at 50pa was achieved by means of wet plaster internal wall lining throughout and airtightness detailing.

Low

Original cement plaster wall lining was not significant

Demand controlled ventilation system

A demand controlled mechanical extract ventilation system was installed with wall vents to the habitable rooms which open and close depending on room occupancy.

Low

Vents are largely located to side & rear of house and have little impact on front façade