Thermographic Survey in Dorchester

Georgian terraces in the centre, 20th-century estates to the west and newer homes around Poundbury create a varied thermal picture across Dorchester. homedata.co.uk records show a median sale price of £335,500, with detached homes at £485,000, semi-detached at £345,000, terraced at £300,000 and flats at £188,000, so the market includes everything from compact apartments to larger family houses. That range matters because each construction type loses heat in a different way. Terraces can share party walls and hide gaps at roof junctions, while flats often show cold spots from exposed corners, balconies or service runs.

Many local homes were built before modern insulation standards were common, which is where our surveys earn their keep. Properties built before 1930 are often better suited to a RICS Building Survey, while good-condition homes from after 1930 may fit a RICS Homebuyer Report, but a thermal scan adds something neither inspection can provide: a live temperature picture. In Dorchester's Conservation Area, where there are 264 listed buildings and the Article 4 Direction came into force on 10 June 2020, changes to windows, walls and roofs can be tightly controlled. A thermal report helps owners and buyers see where heat is lost before they choose the right upgrade.

Period homes here often use Portland stone, Purbeck limestone, flint, chalk, cob, brick and oak, with lime mortars in older walls. Those materials behave differently from modern concrete block and brickwork with polyurethane or rockwool insulation, so the same cold morning can produce very different readings from one street to the next. The River Frome adds another layer, because low-lying parts such as Fordington have a history of flooding and poor drainage, which can leave lower walls damp and colder than the rest of the room. Our surveys make those patterns visible, especially where retrofit work has been added in stages and the finished result is patchy.

• Period masonry needs careful reading
• Retrofit gaps can sit behind apparently solid walls
• Listed homes need evidence before alterations
• Lower walls near flood-prone areas may show moisture cooling

Dorchester's housing stock is mixed in a way that suits thermal imaging well. The 2021 Census puts the civil parish population at 21,358, and the older centre sits alongside Poundbury, Fordington and newer developments such as The Spire at Charminster Farm on Sheridan Rise, DT2. That variety means our thermal imaging specialists often see very different insulation standards within the same postcode sector. A Victorian terrace may still have draughty sash windows, while a newer home can show gaps around vents, pipe runs or partial loft insulation.

Older buildings close to the centre often sit on shallow foundations, which is why minor movement lines, cracked plaster and cold bridging sometimes appear together in the same room. We also see pre-1900 homes with low EPC ratings and outdated heating systems, where the walls look warm in one patch and cold in another because insulation has been added unevenly. Around Poundbury, the problem is more likely to be missed sealant, junction losses and leakage around modern window frames rather than failed masonry. Different age, different story.

The conservation setting changes the order of work. In streets affected by the Article 4 Direction, owners may need to think carefully before altering windows, roof finishes or external wall details, so a thermal survey can point to the real priority before money is spent. Where Portland stone or Purbeck limestone has grown porous, our images often show cooler shaded areas, algae-prone surfaces and damp retention after rain. That gives a practical starting point for repairs, from repointing and ventilation to insulation top-ups and draught sealing.

Thermal images use a colour scale, usually from cold blue through to hot red or white. In Dorchester, a cold patch on a Portland stone wall may mean missing insulation, wind washing or moisture retention, but it can also reflect shade from a neighbouring building on a narrow street near the centre. Our surveyors read the picture in context, not in isolation. That is why the written notes beside each image matter as much as the colours themselves.

Reflections can mislead the eye, especially on glazing, glossy paint or shiny metal flashings. Solar gain can also make one side of a building look warmer in the afternoon, even when the insulation is sound, which is why the timing of the survey matters so much in winter. We check for those false signals, compare neighbouring materials and mark up the image where the reading is real. The result is a report that shows what needs fixing and what simply needs a different explanation.

Every report we produce links the image to a practical action. A cooler strip at the loft hatch may point to a weak seal, while a warm line around a socket can suggest air leakage behind the plasterboard. On older Dorchester homes with sash windows or mixed masonry, we also look for repeated patterns across rooms, because one defect can show up in several places at once. That gives owners a route from image to repair, without having to decode the colour scale alone.

Thermographic surveys in Dorchester start from £300, and that figure covers the core infrared inspection rather than a generic visual check. Our surveyors carry out external and internal scans where access allows, then prepare an annotated report that explains the thermal images in plain English. That report is meant to show where heat is escaping, where moisture may be affecting the fabric, and which upgrades are likely to make the biggest difference. It is a practical way to turn a winter problem into a clear repair plan.

Survey length depends on the size and complexity of the property, so a compact flat in Brewery Square will usually be quicker than a larger period house near the Conservation Area or a home with outbuildings. The on-site part usually takes 1-2 hours, after which we analyse the images and write up the findings. Homes with mixed construction, such as stone walls alongside later blockwork, can need more careful annotation because the thermal pattern changes from one elevation to another. That extra detail is where the value sits.

Accurate results depend on the right conditions. We get the clearest readings from October to March, with the heating on for at least 2 hours beforehand and a minimum 10C difference between inside and outside. If the weather is too mild, or the building has been heated unevenly, the report may need to be rescheduled so the images stay reliable. When the conditions are right, the survey gives a fast, readable snapshot of how the building is performing and where energy is being lost.