Our Somerset surveyors love the variety of house types and styles around the county, and the roofs of the properties we visit are just as diverse! From medieval barns to modern-day homes, Somerset roofs and loft spaces keep our surveyors on their toes. Here are three roof types that commonly give our surveyors something to get their teeth stuck into.
Cruck Roofs
Cruck roofs are made using wooden frames, usually consisting of two curved timbers (often a tree sliced vertically), joined together by horizontal beams. The timbers can either spread floor to ceiling, or be raised on stone walls.
Cruck roofs have been used for centuries, and were particularly popular in medieval times. The Tithe Barn in Pilton, near Shepton Mallet and Glastonbury, is a great local example – this was rebuilt at the start of the 21st century following extensive fire damage. A traditional cruck construction was used, made from English oak.
Nigel Freeman / The Medieval barn at Pilton / CC BY-SA 2.0
In Somerset, jointed cruck roofs are a fairly common type of construction. Jointed cruck roofs use multiple timbers with joints between them. This method extends the lenth of the timber and can alter the shape. Often, the lowest timber piece will double as a straight vertical wall post, and the second timber on top will form the slope of the roof. Surveyors coming across a cruck roof in a period property will consider the possibility that the home would originally have had cob walls; in most cases, these will have since been replaced with narrower stone walls. These alterations can result in the ends of the timbers being exposed to weathering, and they therefore need careful maintenance to prevent decay. The condition of the internal timber and connections are also critical to its structural integrity; surveyors will be checking for signs of rot and infestation, and any general deterioration.
It’s also worth noting that cruck roofs aren’t exclusively found in old buildings – they have had a bit of a revival lately, alongside moves to using more timber in construction and building more sustainable. This new build near Honiton is a great example; it uses scissor, queen post and cruck truss types.
Dry Verges
At the other end of the housing spectrum, new builds in the West Country commonly use dry verges.
Verges are the part of the roof where the tiles meet the gable (i.e. the side edge of the roof). The joint here could provide an entrance for water, dirt and insects into the building, and so it is sealed, either with mortar (a ‘wet’ verge), or with plastic capping (a ‘dry’ verge).
Dry verges are widely used in modern construction, because they are cost-effective and efficient when installed correctly; however we’ve seen thousands of cases where dry verges have failed or been damaged.
They are often fitted incorrectly, and many are made with poor quality plastic; in such cases, water leaks are common, resulting in internal damage and damp. In other instances, water that has seeped into the verge then leaks out and gets blown back onto the gable end, resulting in staining and plant growth. Saturation of the wall with water can also lead to freeze–thaw damage to the masonry during colder months.
Thatched Roofs
Back to period properties again, and Somerset is of course well known for its beautiful thatched buildings. The vast majority of thatched roofs in the county use combed wheat reed. It has been used in Somerset properties for centuries, with the first written mention of this type of thatching dating back to the 1500s. Water reed is seen occasionally, and can be sourced from the Somerset Levels. This can last a bit longer than combed wheat, particularly if a high quality reed is used. However, many thatched houses are listed, which means that owners will usually need to repair and replace thatch using like-for-like materials.
As building surveyors, we look at both the ridge and roof areas.
The ridge is the section along the top of the roof; in Somerset, it is usually lies flush with the roof surface, whereas in other areas a block ridge that stands out from the roof is more common. The ridge is the most likely area to show damage, because it is the most exposed. Fortunately, the ridge can be repaired alone, without needing to replace the entire roof – this is vital for prolonging the life of the main bulk of the thatch.
A combed wheat ridge typically needs replacing every 10 years or so, whereas the rest of the roof should last at least 20 years. Steep pitched roofs tend to last longer, as do roofs that can dry out easily; roofs that have trees overhanging them deteriorate more quickly.
During a building survey, we will be looking at the condition of the ridge and all elevations of the roof, and commenting on the remaining lifespan and whether any interim maintenance is required.
