Most individuals when buying a property accept the survey findings and if the report says that the roof requires a certain amount of work, they will be resigned to having the work completed or perhaps negotiate a cheaper price before purchase to compensate for the cost of repairs. What happens after this is that no further thought is given to the roof, people rest on their laurels thinking that they will not need to take any further interest in roof maintenance.
What they fail to realise is that a roof has a finite life span and it is inevitable that if it has been repaired once, it will more than likely need further repairs within the next 3 – 5 years. It might even be that case that it will need complete renewal eventually and, if it is an older property, it is quite common for the roof to require extensive work to be carried out within about 7 – 10 years of ownership. Obviously most homeowners and landlords would want to avoid the costs of a replacement roof and prefer to have it patched up for as long as and as far as possible. Common problems and repairs are outlined in the following sections.
Problems with older roofs
Slates and tiles and their fixings are subject to plenty of variance in temperatures and weather conditions. As such, it is inevitable that the roof covering will show signs of age and wear over a period of time. Initially, the first sign of materials failing is chinks of light appearing through cracks in the loft or attic. A visual inspection externally may also reveal cracked or slipped tiles or slates, or delaminated slates. The weather causes the tiles or slates to fracture or break, but movement within the actual roof structure can also cause slippage, especially if the fixings are decaying.
Delamination of roofing materials
Delamination can also occur in both slate and clay tiles due to their structure and manufacturing techniques. This is the term given to the process where water is absorbed by the slate or clay material. In the winter, water freezes and therefore expands which can fracture a layer and splinter it off. This compromises the water repelling properties of the roofing material and can lead to the inevitable problems with leaks and damp internally.
Bowed or sagging roof
A very obvious problem that is easy to spot from an external viewpoint is whether there is bowing or sagging to the roof. Any dip in the shape of the roof is indicative of a very serious problem that will require urgent remedial works. A sagging roof strongly suggests a problem with the timbers that support the roof structure. They may be rotting or decayed or have become loose. However, it is also possible that the building may have moved and been affected by settlement. Rotten or loose timbers cannot support the roof for a long term and they will need replacing or repair works as soon as possible. Failure to address this problem could result in a total collapse of the roof as the remaining supporting timbers are not designed to take on extra stress and weight and are liable to fail as a result.
Cracks in mortar joints
Other signs of a problem will be manifested as cracks. Cracks can appear on the ridge, hips and verges, especially in the bedding mortar joints. This indicates that the mortar has perished and is no longer acting as a jointing material. Again, this will require prompt attention as water can penetrate this type of crack readily and make it worse in a relatively short space of time. This will obviously have implications for the internal structures and decor of the property.
Cracks in mortar flashings
In the 1940’s it was very common for flashing to be made from mortar fillet. This was a far cheaper material to use than lead and much easier to acquire for the builder. Problems arise with these older styles of roofs because mortar fillet is vulnerable to the freeze-thaw effect of the British winter and cracks are therefore very common in this style of roof. Again, this has implications for the internal parts of the property as water can penetrate, causing damp and damage.
Cracks in metal and lead flashings
Post 1940, it was more common to see flashings made from lead and later, zinc. Although these materials are more resistant to the effects of the British climate, they can still perish and become cracked which can give rise to serious leaks. It is accepted that a sizeable proportion of failed lead and metal flashings can be explained by poor workmanship when they were installed because if they are installed correctly, they can easily last for the life of the entire roof.
Dealing with problems in an older roof
The obvious question when it comes to addressing problems in an older roof is whether it is economically viable to mend it or strip it right off and renew it to current regulations. If there is a likelihood of another problem cropping up following a repair, then it will probably make more sense to renew the roof as it will be more cost-effective in the longer term.
Scenario: slippage of slates has been observed, and an order has been raised to refix them as necessary. The roof requires scaffolding in order for this to be carried out which is an added expense. The roofer re-fixes the slates but notices a slight dip in the roof outline. A few months later, more slates slip and fall away from the roof and the same job is ordered again. This will continue to happen as it is clear that the roof tile fixings have perished and cannot cope with the stresses placed on them. Additionally, damp has ingressed and affected the timbers, requiring greater intervention from a surveyor or structural engineer who could require complete renewal of the roof.
Solution: Get advice early on even if it is just a couple of slipped tiles or slates as they could be a symptom of a much bigger problem.