The Industrial Revolution resulted in a huge increase of houses built during the reign of Queen Victoria (1837 to 1901), which are now a common feature throughout British towns and cities. Typical details, including high ceilings and good-sized rooms, have made these properties highly attractive to potential buyers. Unfortunately, this type of construction bears some inherent defects.
Below is a list – not exhaustive – of common defects to consider when looking at purchasing a Victorian property, or, even if you already own one and would like to understand more about your property. Please do contact us if you have questions, or would like to arrange a survey for damp / waterproofing related issues, structural reinforcement and/or Timber Treatments.
Most Victorian properties are constructed with solid masonry walls, which are often relatively soft, red or yellow London stock bricks. This type of construction is prone to rainwater penetration; particularly during periods of prolonged wet weather where damp masonry does not have the chance to dry out before more rain from wet weather is absorbed. Where bricks have absorbed a lot of moisture, it can, over time, penetrate through to the internal surfaces. Defects with rainwater goods including roof guttering, downpipes and gullies, etc. all contributing to rainwater penetration and are common with buildings of this age. If bricks have “spalled” or pointing has loosened, this too can increase the risk of rainwater penetration.
Rising damp is the upward movement of moisture, through capillary action, into the structure. This process is not limited to external walls and can affect any wall in contact with the ground, including internal party walls, spine walls and other walls. Many Victorian houses benefit from a damp proof course (DPC) of some description; the most common being slates but also lead, pitch asphalt or low absorption (engineering) bricks.
Where moisture rises above the level of the DPC, a failure, or a compromise of the DPC is likely. This could be caused by a number of reasons, including:
- The DPC being badly laid during construction (unlikely)
- Structural movement causing cracking (particularly in slate)
- “Bridging” of the DPC where ground levels have been raised over the years
- Or, far more commonly, inadequate connection between newly built sections and the existing DPC, which also results in bridging (of the existing DPC). This is when a porous material is placed over the top of the DPC allowing moisture to bypass the DPC altogether and migrate up the wall.
The good news is, with the use of thixotropic creams the DPC can be reinstated. However, the residual moisture within the wall will contain chlorides and nitrates, which it picked up on its journey through the ground. These are hygroscopic salts, which attract moisture from the atmosphere and also from the substrate. When this occurs to an unacceptable degree, it is necessary to replace the contaminated plaster with a specialist render, or lime based, vapour permeable renovating plaster, which prevents the movement of hygroscopic salts to the internal finishes.
Victorian solid wall constructions are less thermally efficient than modern cavity wall constructions which means they could be more prone to condensation issues; more so, when modern less drafty windows have been installed. This is because moisture vapour, produced by the occupants in one form or another, is unable to escape. Condensation is a consequence of poor ventilation and/or inadequate heating. Warm air can retain more moisture then cold air. This means when moisture Laden warm air comes into contact with a cold surface, the moisture can no longer be retained within the air and is deposited onto the cold surface.
Another, very common cause of condensation within Victorian buildings, is when properties which were houses are converted to flats. This results in a complete change of internal layout which is not always conducive to good air movement within the property. It also tends to introduce more bedrooms on each level, which tend to be closed rooms and more prone to condensation. The desire to make rooms draught free, so that they are warmer places to be in, is wholly understandable but can end up causing a condensation problem which was not there historically.
A common feature of a Victorian property is a suspended timber floor at ground level. A typical method of construction is to span timber joists across the width of the room, resting on timber plates which sit on top of masonry “sleeper” walls or sub-floor level brick piers. Floorboards are then placed on top of the joists to form the floor. These floors are typically suspended above soil. The space in between the floorboards and the soil, which can vary significantly from property to property, is referred to as the sub floor void, or oversite. Adequate sub floor ventilation is required to allow any moisture build up, within the sub floor, to evaporate and vent out to prevent timbers in the sub-floor void becoming damp. In an ideal situation, this requires through ventilation from the front of the property to the rear. Sub-floor sleeper walls should be adequately honeycombed with no debris to hinder the passage of air. Unfortunately, it is often the case that very little consideration is given to sub floor ventilation when Victorian properties are extended. As a result, cutting off through ventilation and allowing moisture build-up within the subfloor. If this occurs, it can lead to sub-floor condensation and in turn, can result in fungal decay in the floor timbers.
Victorian properties are particularly prone to certain structural defects. It is fair to say, any domestic property could be subject to subsidence, given the right conditions, but Victorian properties in particular are more likely to suffer with lack of lateral restraint, roof spread, lintel failure and differential movement (particularly in bay windows). Lateral restraint is a connection between the wall and internal floor, or roof structure preventing the outward movement of the wall. Victorian properties often have joists running from front to back providing restraint to the front and rear elevations, but little or no connection to the flank walls.
Roof spread occurs when rafters are not supported adequately within the roof void. This is a common occurrence when relatively lightweight slate roofing tiles have been substituted for heavier concrete roof tiles, generating a greater download force, trying to flatten the pitch of the roof and subsequently pushing external walls outwards. Victorian brick arch lintels rely on compression through the various elements to support the brickwork above. If this compression is compromised, normally through movement elsewhere e.g lateral movement, then the lintel will drop and normally present with diagonal cracking above the window. Differential movement within bay windows is typical in Victorian properties, as the bay was normally constructed on a separate Foundation to the main building. This was primarily to avoid destruction of the bay window in the event of movement to the main property.