Looking after an old stone or thatched home in West Oxfordshire

Much of West Oxfordshire is built from the ground beneath it. The district council's design guide describes geology "dominated by 150 million-year-old Jurassic rocks", with a thick belt of oolitic limestone forming the Cotswold hills, and notes that roughly a third of the district lies within the Cotswolds National Landscape (renamed in 2023, but still legally an Area of Outstanding Natural Beauty). Older houses here were built to work in a particular way. This guide sets out general principles only; where work is planned, speak to the council's conservation team early.

How old stone walls handle moisture

Traditional stone houses were not built to keep water out completely. They were built to let it dry out again. The Society for the Protection of Ancient Buildings (SPAB) explains that buildings from before the mid-19th century "rely on allowing the moisture which has been absorbed by the fabric to evaporate from the surface." West Oxfordshire's own guidance notes that older walls generally have no damp-proof course and manage moisture by evaporation.

That is why the material between the stones matters so much. The council's stonework guidance is direct: "Dense, cement-rich mortars are not appropriate for limestone" because "they do not allow the free passage of moisture from the wall." SPAB recommends instead "a soft lime mortar with rough texture and lower strength than surrounding masonry", so the pointing, not the stone, takes the weathering.

• Pointing style. The council's guide says joints should be thin and finished flush or slightly recessed. Projecting "ribbon" pointing "traps moisture in the wall, is not traditional" and is best avoided.
• Renders and paints. SPAB notes that strong cement renders tend to develop hairline cracks, let water in and then stop it escaping. SPAB adds that modern exterior paint systems tend to stop moisture evaporating from the surface. Lime render and limewash are the traditional, porous alternatives.

Damp: find the cause before treating it

Damp is often blamed on "rising damp" when the source is simpler. Guidance from neighbouring Cotswold District Council lists blocked or damaged rainwater goods first among the common causes, alongside leaking pipes, failing roofs, blocked airbricks and ground levels "raised directly against the building".

The same Cotswold guidance advises against cement plaster or render, injected damp-proof courses, tanking and waterproof paints in historic buildings, as these may make the problem worse. Where the cause is not obvious, it recommends a suitably qualified surveyor working to the British Standard for the conservation of historic buildings (BS 7913). Sensible first steps:

• Clear gutters, hoppers and downpipes, especially after autumn leaf fall.
• Check that soil, paving or flower beds have not crept up the outside of the walls.
• Be wary of any survey that recommends chemical injection or tanking without first looking at drainage and materials.

Stone slate and thatch roofs

West Oxfordshire's roofing guidance describes natural limestone slate and thatch as defining local roof types. Stone slates are traditionally laid in diminishing courses, with the smallest at the ridge, and the eponymous Stonesfield slates "have been especially highly regarded for their quality and evenness." The council says natural stone slates "should be retained or replaced on a like-for-like basis wherever possible", using matching salvaged slates or new slates from a quarry still producing them. On listed buildings, swapping to alternatives, including artificial slates, "will generally not be supported".

Thatch is concentrated in the Thames Vale. The council notes that combed wheat reed has almost entirely replaced traditional long straw locally, and that a good long straw roof should last 25 to 30 years, with the ridge usually needing renewal at around 12 to 15 years; it gives combed wheat reed the same timescale. Historic England notes that patch repair can extend a roof's life and delay a full re-coat, and warns that on a listed building, changing the thatching material, for example to water reed, will need listed building consent, and suggests applying at least two months before work is due to start.

Windows: repair first, then improve

Historic England's guidance on traditional windows says they "can be simply and economically repaired, usually at a cost significantly less than replacement". It describes draught-proofing as "one of the most cost-effective and least intrusive" improvements, and reports that secondary glazing can reduce heat loss through a window by nearly 60 per cent.

West Oxfordshire's guidance adds that draught-proofing is unlikely to need consent even on a listed building, that internal shutters can be a cheaper alternative to double glazing, and that uPVC "is seldom appropriate for traditional buildings." Cotswold District Council's window guidance offers one useful caution: if you fit secondary glazing, the original single-glazed window should not also be draught-proofed, to avoid trapping moisture between the two.

Consents: listed buildings, conservation areas and the National Landscape

Listed buildings. West Oxfordshire District Council states that listed building consent is required for alterations and extensions and "applies to both the exterior and the interior of the building." Unauthorised work "constitutes a criminal offence", there is no time limit, and liability can pass to new owners. Work that changes materials, such as new windows or a different roof covering, may well need consent, so ask first.

Conservation areas. The council lists 50 conservation areas in the district. Designation reduces permitted development rights, and it lists "some extensions; some alterations to roofs, windows and doors; some types of cladding" as examples that may need planning permission. You must also give six weeks' notice before lopping, topping or felling most trees.

The Cotswolds National Landscape. Government guidance on householder permitted development treats Areas of Outstanding Natural Beauty and conservation areas in the same way: cladding the exterior, extending beyond a side wall, building rear extensions of more than one storey and roof extensions all need planning permission. The council decides applications; the Cotswolds National Landscape Board comments on some.

Where to get advice

• West Oxfordshire District Council conservation team. The council's historic buildings and conservation pages include conservation area maps. The council's heritage guidance says it offers general advice free, with more detailed guidance through its pre-application advice service; check the current arrangements before you ask.
• The West Oxfordshire Design Guide, with sections on stonework, roofs and conservation areas.
• Historic England, for technical guidance on windows, thatch and listing.
• SPAB, which runs a technical advice line for people with questions about old buildings.

When choosing tradespeople, ask about their experience with lime, stone slate or thatch, and with listed buildings. Browse local firms in our roofing and builders and renovation directories.

Cover photo: a thatched stone cottage in Minster Lovell, by No Swan So Fine, CC BY-SA 4.0, via Wikimedia Commons.