Period Terrace

Heating system

A number of heating systems could be difficult for this house type. Bulk LPG, solid fuel, wood pellet and oil might present difficulties for delivery and storage of fuel if access for delivery vehicles is restricted. Ground source heat pumps function most efficiently with a low temperature delivery system such as under-floor heating, which is not suited to suspended timber floors. If the suspended timber floor is replaced by a new solid floor then ground source heat pumps could be considered. If many adjacent properties are being treated then community heating may be an option.
Preferred heating systems are therefore:

1. Gas central heating (if gas is available)
2. Electric storage heating with automatic controls
3. Air source heat pump, when more commonly available

Stored hot water could be supplemented by solar hot water.

Insulation measures

Walls

The most viable wall insulation would be internal insulation supplemented by flexible insulated linings where the extra thickness of internal insulation creates problems. If the entire terrace was being treated external insulation would be best technically. There may be planning issues for external insulation, however. Internal insulation may be difficult to detail to avoid cold bridges.

Glazing

Timber sash windows are often difficult to draught strip effectively, particularly if frames have racked due to settlement. There are specialist companies who undertake to refurbish and fit effective draught stripping to sash windows.
Because of the relatively large proportion of glazed area on external walls high performance double glazing would be beneficial although may not be allowed in conservation areas etc. Alternatively secondary glazing may be a good option, but attention needs to be paid to egress in case of emergency and need for rapid ventilation in 'wet' rooms such as bathroom and kitchen.

Floor

Suspended timber floors can be quite draughty, especially if square edged boards have been used. Effective draught sealing of the entire floor (for example by applying hardboard or similar and sealing around skirtings with mastic) would increase comfort levels markedly. If floor boards are replaced insulate between joists. If the whole floor is replaced an insulated concrete floor could be considered.

Roof

Lofts are frequently inaccessible due to low pitch and the need to maintain cross ventilation can make loft insulation difficult to install. Insulating the underside of the first floor ceiling can be quite practical, particularly if lath and plaster has become detached. If slates need to be replaced insulate the roof at the same time, either by conventional loft insulation (use breathable sarking to help deal with the ventilation issue) or by insulating at rafter level thus creating a warm roof. However, rafter level insulation increases the height of the roof, which may be problematic unless the roof line is broken by steps and staggers, or the party walls project above the roofline.

Ventilation

Background ventilation should be provided in habitable rooms. Trickle vents can be fitted to existing windows, but this may not be practical for some types of frame such as sliding sash windows. In that case other means of providing background ventilation should be explored, such as provision of 'through the wall' vents (although these are easily sealed up by tenants) or by the omission of at least 2m of draught strip per room.
Passive stack ventilation in kitchens and bathrooms can be fitted during the conversion process, although routing ducting (which needs to be near-vertical) may be difficult. Rooms in upper floors may be more straight-forward. Extract fans should be fitted in situations where passive stack ventilation is not practical. Positive pressure ventilation is also worth considering, particularly in dwellings with condensation problems.