Internal wall insulation in Kings Heath and Moseley.

What are Kings Heath and Moseley terraces usually built like?

Most were built in the late Victorian and Edwardian period with solid brick walls, typically around 225mm thick, laid in lime mortar. A typical layout is a front room with a bay, a middle room, and a back addition with the kitchen downstairs and a bathroom or small bedroom above. Larger villas in Moseley have taller rooms and more original detail.

Many have been modernised over the years with gypsum plaster, cement pointing and sealed windows. Those changes can affect how the walls handle moisture, so I look at them before choosing a system.

How do you insulate a back addition without losing too much space?

Carefully, because the rooms are narrow. A galley kitchen or small bathroom can lose noticeable width if both long walls are insulated thickly. I weigh three things: how cold the wall is, how much space you can spare and how much moisture the room produces.

Thickness is typically 20mm to 80mm per wall including plaster. Moisture modelling tells me how far I can go safely on each wall.

We are planning a new kitchen. Should we insulate first?

Yes, if you can. Insulating while the old units are out saves taking them off and refitting them later, and the new kitchen is fitted to the new wall line from the start. It is one of the best moments to deal with a cold back addition.

I can work to your kitchen fitter's timetable so the walls are insulated and plastered before they arrive. Ventilation, such as a proper extractor, is worth planning at the same time. The guide to living at home during the work explains how the house stays usable.

Do these houses need lime and breathable insulation?

Often, yes. Old solid walls built with lime mortar move moisture through them, and a breathable system lets that continue. My usual choice here is wood fibre boards finished in lime, around £3,000 per wall and about five days. PIR, usually £2,300 to £3,000 over three to four days, can suit a sound, dry wall, but only after a moisture check.

The lime versus gypsum guide and the Victorian home insulation guide explain why I am cautious with impermeable materials on old walls.

Can I insulate inside a house in the Moseley conservation area?

Usually, yes. Internal insulation does not normally need planning permission because the outside of the house does not change. Listed buildings need listed building consent for internal work. In conservation area houses I take extra care with cornices, ceiling roses, picture rails, deep skirtings and sash window reveals, and I finish in lime where the original plaster is lime.

The front bay and the back bedroom both have mould. Which first?

Usually the back bedroom, because the back addition combines the coldest walls with the most moisture. But a Victorian brick bay can also be cold, especially around the angled corners and the window reveals. The Birmingham bay window insulation page explains how brick bays differ from the lightweight bays in 1930s semis.

If mould keeps appearing behind furniture, the guide to mould behind a wardrobe explains why it is often the first sign of a cold wall. Existing mould should be removed safely, with a mask, before any work.

Kings Heath is a long way from Walsall. Do you still come?

Yes. It is usually 40 to 45 minutes from Bloxwich, and I plan surveys in advance so the journey is not an issue. The process is the same as anywhere: free home visit, moisture check, written quotation, pre-start guide and a follow-up call about four weeks after the job.

I also cover Hall Green, Harborne and the rest of Birmingham. See the full process.