Begin with the building, not the mood board

Period cottages were built by people who understood their local materials far better than we do. Before you order a single tin of paint, spend a few weekends getting to know what you actually own. Is it timber frame with wattle and daub infill, solid brick, cob, or stone rubble? Each behaves differently, and the wrong intervention can cause damage that costs more to undo than the renovation itself.

Commission a building survey from someone who specialises in older properties, and if there is any sign of movement, a structural engineer with period experience. Look for the usual suspects: cement render trapping moisture in solid walls, blocked airbricks, leaking gutters staining the brickwork, and historic roof spread pushing walls outwards. If your cottage is listed, or sits in a conservation area, talk to the conservation officer at the local authority before you draw up plans. Early conversations are free; enforcement notices are not.

Let the walls breathe

This is the single most important principle in period renovation. Old walls are designed to absorb moisture and release it again through evaporation. Cement render, gypsum plaster and modern vinyl paints seal the surface, so trapped water has nowhere to go and instead pushes out through the brick or timber, often as rot or blown plaster at low level.

• Remove cement render and repoint brickwork and stone with a lime mortar matched to the original mix and colour.
• Replaster internally with lime or clay, and finish with breathable paints such as limewash, clay paint or a mineral system.
• Avoid silicone sealants on external walls; use lime mortar or traditional mastic instead.
• Repair gutters, downpipes and drains first. Most "rising damp" in cottages is really a leaking gutter soaking the wall for years.

Breathable materials are slower to use and less forgiving of impatience, but they are the reason these buildings have survived three hundred years and will survive another three.

Insulate without creating a damp problem

You can make a cottage noticeably warmer without smothering it. The trick is to use vapour-permeable insulation and to keep a route for moisture to escape.

• Loft: top up to around 270mm using mineral wool or a natural equivalent, but never block the eaves ventilation. Fit a breathable membrane if you are insulating between rafters.
• Solid walls: wood fibre or cork boards fixed to battens, then lime plastered over. Keep the build-up thin and hygroscopic rather than reaching for foil-backed products.
• Floors: lift a few boards in a suspended timber floor, drape netting between the joists and fill with sheep's wool batts. Keep the external airbricks clear so air still moves beneath.
• Draughts: tackle these before anything else. Chimney balloons, brush seals on sash windows, and a letterbox flap cost very little and make an immediate difference.

Keep your original sash windows where you can. Secondary glazing, draught strips and good curtains perform well and preserve the character that made you buy the place.

Heating, hot water and flues

Old cottages are usually fitted with boilers that are too powerful for the space and radiators that are too small. The result is a system that cycles on and off and never feels truly warm.

If you are considering a heat pump, insulation and draught-proofing must come first, along with larger radiators or, where possible, underfloor heating. Underfloor heating suits a cottage only if you are already lifting the floor and can afford the lost head height. Otherwise, size radiators generously and insulate the pipework. Wood-burning stoves need a lined flue, a compliant hearth and, in smoke control areas, a DEFRA-exempt appliance. Building regulations approval applies here, so involve your local authority building control team early.

Reconfiguring the layout carefully

Cottages are small and low-ceilinged by modern standards, and the temptation is to knock everything through. Resist it. Removing walls rarely solves a space problem as neatly as better storage, a well-placed opening, or a modest extension.

Where you do remove a load-bearing wall, expect a steel beam, padstones and a structural engineer's calculations. Moving a staircase is expensive and disruptive, and in listed buildings almost never approved. If you are extending, matching local materials — the same brick, lime mortar, slate or clay tile — will look far better and often costs no more.

Budget, sequence and living through it

Set a contingency of at least twenty per cent, and twenty-five if you are uncovering a building that has been altered before. Work in the right order: roof, rainwater goods and drainage, then damp and structural repairs, then services, then insulation, then plaster and finishes. Doing the decorative work before the rewiring is the classic beginner's mistake.

If you can live on site, do one room at a time and keep a functioning kitchen and bathroom for as long as possible. Photograph everything before you cover it up, keep all consents, certificates and product receipts in one folder, and accept that a period cottage will always ask a little more of you than a modern house. That is part of the charm.