Hot Property

The combination of very cold weather and the introduction of basic heating in my ancient house has provided enough of a contrast between internal and external temperatures over recent months for some useful infrared thermography (IRT). I’ve been very fortunate to have had assistance with this from Mark Hurst of Anglia Ruskin University/1st Associated (www.1stassociated.co.uk).

Mark’s FLIR B40 camera detects differences in surface temperature caused by variations in heat flow thorough materials and records the results in the form of a thermal image (thermogram). This offers a convenient, non-destructive method of investigation. It’s helped me not only to pinpoint where most heat is being lost through the building’s fabric but with determining the pattern of timber framing hidden beneath render.

From the IRT camera I now know that the areas associated with the poorest thermal performance include the single-glazed windows and floors of the overhanging upper storeys. These will be addressed during the project but the IRT has also shown that my use of cling film and masking tape as a temporary expedient behind a draughty window is already paying dividends!

Winter Warmth

Both my cottages currently lack central heating so last autumn I purchased several oil-filled radiators to temporarily provide some warmth. Given the age of my electrical installation, I took the precaution of connecting these using plug-in RCD adaptors (www.masterplug.com).

The radiators are controlled by thermostats, which help maintain steady room temperatures. I’m conscious that old timber-framed buildings are similar to fine antique furniture in the sense that sharp variations in relative humidity caused by large temperature fluctuations can distort or crack the wood. In my case, this could also harm some of the fragile internal plasterwork that’s awaiting repair.

The data loggers I’m using show that the heating has created a more stable internal environment. The only snag has been that one of the heaters developed a small oil leak. Fortunately, I discovered this before any damage was done to the building fabric and the supplier replaced the faulty unit immediately. The previous day I’d ordered a couple of extra radiators. By chance, they’re oil-free.

Jack Frost

The recent very cold spell severely hampered work on local building sites. A contractor employed on a nearby church where work to a flint wall had been adjourned until the spring commented to me how a 1 tonne bag of sand had been transformed into a single, large, frozen cube, joking that you’d need a jackhammer to break into it.

At home, the sub-zero temperatures have fractured the second of my outside WC pans, even though I’d drained it of water. My other external WC, the rim of which was damaged last winter, now causes great amusement for my two young nieces. Every time the lavatory is flushed it sends up a fountain of water in the direction of unsuspecting users!

Frosty conditions are said to improve the quality of lime putty in storage, though, of course, it must be allowed to fully thaw before use. I picked up some more the other day when visiting conservation builder Anthony Goode (www.ajgoodeconservation.co.uk) and added this to the other tubs I’ve left maturing in one of the yards. The longer the putty is stored, too, the better it becomes. Lime will be a key ingredient in the work I’m planning.

Enduring Local Interest

I hosted a visit the other day for about a dozen local people representing the Recorders of Uttlesford History (www.recordinguttlesfordhistory.org.uk). The group was set up to record the present and ensure that valuable artefacts and archives of the past are conserved. The Recorders wished to see my property in its current unrenovated condition and plan to return again later.

Over the years, there’s been much local interest in the range of buildings that includes my cottages. When purchasing them, I discovered that local donations and a wider appeal helped the Ancient Buildings Trust (ABT) acquire the range in the 1930s to protect it from possible harm. The ABT was the property-holding arm of the SPAB, who, coincidentally, I work for!

To secure the donors’ gift should the ABT sell its interest, it took a long lease and vested the freehold in the National Trust. The ABT sold its lease in the 1960s after overhauling the greater part of the range. However, it hadn’t been able to gain vacant possession of what are now my two cottages to modernise these. They’ve changed little since, so in many ways I’m picking up where the ABT left off over 40 years ago.

Monitoring Temperature and Humidity

Every month I’m downloading onto my computer readings from half a dozen data loggers that I have distributed around the property – five inside and one outside. The idea is to identify any locations where the fabric might be at risk of deterioration due to condensation, as well as to obtain a clearer picture of how the building is performing in order to help guide me with the changes I make to the levels of thermal insulation and ventilation as part of my renovation project.

I purchased the loggers online from www.tomsgadgets.com (Lascar EL-USB-2). They record air temperature, humidity and dew point (the temperature at which water vapour in the atmosphere begins to condense). The devices, which are battery-operated, are currently set to sample at hourly intervals. The data stored is downloaded by plugging the logger straight into a computer’s USB port and running the purpose-designed software that comes with it. The data can then be graphed, printed or exported to other applications.

The monitoring has already enabled me to establish that I need to improve the conditions in one of my roof spaces to reduce the likelihood of condensation and associated timber decay.