When it comes to roofing, maintenance is always better than refurbishment, explains the National Federation of Roofing Contractors
Keeping schools fit-for-purpose and safe for staff and pupils is a key priority for all head teachers. From staying on top of general maintenance, to knocking down unsafe or dilapidated parts of the building, or adding new classrooms, it’s a delicate balancing act around funding, health and safety, and even school closure.
One area of maintenance that schools can’t afford to overlook is the roof. One of the most dominant features of the building, it represents a sizeable investment too. Whilst correctly installed roofs will often last decades – and in the case of natural slate, a lifetime – it is often assumed that they require zero maintenance or attention. However, they are constantly in the frontline of weather abuse, so regardless of its age, ongoing maintenance and repairs are vital to avoid facing large bills for replacement – not to mention possible damage to the interior as a result of leaks.
Installing a new roof is a luxury that most schools can only dream of. Many post‑war built schools generally have a number of flat roof areas, as opposed to traditional pitched roofs, and these can be prone to problems if not maintained correctly.
Short term solutions can be fine but they don’t always fix the job properly in the long‑term. Spotting roofing problems early can save a fortune, but how often should the roof be inspected, what should be looked for, and when to call the specialists in?
Regular inspection of the roof can go a long way to spotting problems early and taking action. However it must be stressed that inspecting roofs must be carried safely and carried out by a roofing professional tarined at working at height rather than a schools general maintenance operative.
When Autumn comes, it’s important to clear the roof and gutters of leaves and other debris, and to inspect it after any storms with heavy winds. Roof tiles or slates that have broken, slipped out of place, or even blown off are a common occurrence. If they are not replaced, rainwater can saturate supporting timbers and get into the inner roof structure causing damage.
Gutters, gullies and downspouts should all be cleaned in late Autumn after the trees have shed their leaves. It’s also important to check for breaks or gaps in the joints (obvious drips, green staining on the walls or path), and make certain that the brackets holding the gutters against the building are securely attached.
Other parts of the roof can cause leaks and damp, including the flashings and masonry. Wind and weather can get underneath defective flashing and rip it loose allowing water ingress. Equally, If there are trees growing nearby, they may need to be trimmed back. Leaning branches can dislodge roofing materials when blown by the wind and falling branches can damage tiles, and falling leaves can clog gutter.
Flat roofing problems
A flat roof is generally defined as having a pitch not greater than 10° to the horizontal. A truly flat roof would not allow rainwater to drain away, so most flat roofs have a fall on them to enable the rainwater to naturally flow to collection points. Over the years, the waterproof coverings may have been overlaid or replaced with another bituminous system, or with a polymeric or rubber single ply waterproofing or a GRP based liquid applied coating.
Today, built-up RBM (Reinforced Bitumen Membranes) are the most common material for flat roofs. Thanks to RBM and other systems, leaky roofs that were once expensive and troublesome to maintain are now a thing of the past. Flat roofs are now low maintenance and can enjoy a trouble free life expectancy of up to 35-40 years.
When problems do occur with flat roofs, it’s usually due to leakage caused by the failure of the waterproof covering. This may be due to several factors such as bad design, poor detailing, bad installation and inappropriate materials. Other causes can be an inability to withstand movement, thermal shock, impact or other damage, the deterioration of seams, trims or flashings, failure of previous repairs, lack of maintenance or simply the waterproofing material reaching the end of its service life. Damage can also occur as a result of actual foot traffic on the roof caused by non-specialists gaining access.
Ponding of rainwater can often occur on flat roofs. Although it is not necessarily a problem in itself, it may be an indication of the degradation of the supporting deck due to water ingress or condensation. It may also indicate the lack of fall to the roof, which may be addressed when refurbishing. Blistering may be present but, and although not problematic, it should be monitored periodically.
If re-roofing is required, then a suitable roof covering will need to be decided upon. If it’s just a portion of the roof that requires refurbishing, then it’s likely that the same covering would be chosen to match the original. Whilst there are a medley of options to consider, including slate, clay, concrete tiles and green roofing, a key factor governing this choice will be budget, of course.
Refurbishment projects tend to make up 50 per cent of a local authority’s funding under the government’s Building Schools for the Future (BSF) programme – so it’s important that these significant sums of money are spent wisely and effectively.
Thanks to the current British Standard Code of practice for slating and tiling, BS 5534, which revised in 2014 and further amended in 2015, new and refurbished pitched roofs have to be more secure in the face of increasingly extreme weather events. New minimum performance standards for underlay as stipulated by the Standard also mean that new roofs are more energy efficient too.
Refurbishment of a roof is likely to be reportable to the Local Authority Building Control (LABC) and approval under Building Regulations must be sought, unless the contractor is a member of CompetentRoofer. Current regulations stipulate that if more than 50 per cent of the existing waterproofing is being stripped, if it’s technically and economically feasible, the whole roof must be brought up to the standard of the current energy related regulations.
This means that a roof will require substantially more insulation than is currently present. Part L of the Building Regulations may require additional thermal insulation to all re-roofing projects where the building underneath is heated.
For example, a school’s flat roof installed in 1995 will possibly have about 40mm of rigid polyurethane insulation meeting the then current regulations. In 2012, however, that thickness increased to 140mm. Particular attention needs to be paid to any condensation issues that can occur on existing roofs of a cold design and accommodated when renovating.
Green or vegetated roofing has become increasingly popular over recent years. Whether it’s transforming a humble outdoor storage building or landscaping main parts of the roof, green roofing offers a planting system that not only looks great and helps soften the look of the school, it’s brimming with environmental, social and economic benefits too.
In urban environments, green roofs help attract the birds and butterflies and provide cleaner air, offsetting our carbon footprint and helping combat global warming. They can also help reduce the need for air conditioning in the summer, and offer a degree of additional insulation in the winter. The lives of waterproofing membranes beneath green roofs are extended, plus sound insulation is improved. Also, water surface run-off can be reduced.
In a school, a green roof can provide pupil interest and generate a feeling of well‑being amongst both staff and pupils. They can be installed as a complete system and can even be retrofitted to existing roofs.
The revised Green Roofing Organisation (GRO) Code is designed to provide assistance for anyone who is involved in the design, specification, installation or maintenance of a green roof.
Calling the specialists
Other than simple maintenance issues such as clearing leaves and cleaning gullies, it’s important to call in the specialists from the outset. Trained and competent roofing contractors will not only be skilled in all aspects of roofing, they will be conversant with the latest regulations and knowledgeable about other potential risks, such as from asbestos-containing materials.
By appointing a contractor who is a member of the National Federation of Roofing Contractors (NFRC) government‑approved CompetentRoofer scheme, schools can enjoy significant cost savings. Through self-certification, these specialists can eliminate costly and time-consuming local authority building control procedures, whilst maintaining performance and legality.
Many older schools are listed buildings and require special attention to detail and consideration. Contractors with specialist skills to carry out such repairs or refurbishment work may be found via the NFRC’s National Heritage Roofing Contractors’ Register which is recognised by all UK Heritage Agencies.
Roofs help protects schools from all types of weather, but without maintenance, the roof will age until it is no longer able to do its job. If problems are encountered, it’s important to seek the help of a specialist roofing contractor immediately. After all, lining up buckets to catch the rain falling from leaks in the ceiling, or having to teach pupils in temporary classrooms are the last thing that any school wants.