Leaking flat roofs can be a costly endeavor – particularly if the source of the leak has spread into other areas of the roofing structure or building. The following article outlines reasons why your flat roof is leaking and what the best strategy is to fix it.
Why is my flat roof leaking?
The obvious primary reason for a leaking flat roof is that there is a hole in it!
What type and how it was caused is another matter.
The following lists the 5 main reasons for failure.
- Poor installation: a poorly installed flat roof will lead to rapid failure and ingress of water from multiple areas. This applies to mineral felt, glassfibre and single ply installations highlighting the need to engage only proven contractors who can provide Insured Guarantees and have a sound reputation.
- Age: the age of your roof will also have an impact on its watertightness. UltraViolet (UV) light will through time erode most surfaces and can cause embrittlement particularly in the case if mineral felt roofs at the perimeter welts.
- Damage: walking without due care on your flat roof can often cause subtle hidden damage particularly with mineral felt and single ply installations. A well laid glassfibre roof system has greater resistance to foot traffic and impact damage. Is also impervious to extreme temperatures. A hot summer can soften a mineral felt installation causing blistering. Cold icy winter conditions combined with foot traffic pressure on any blisters will result in a fractured surface.
- Joint leaks: ingress around skylight installations can often be a source of failure occurring around poorly detailed curb upstands or damaged glazing panels and seals.
- Lead flashing: as much a culprit as any of the above is the lead flashing installation. Time and again we identify failure of a roofs watertightness due to poorly installed leadwork particularly because of inadequate recessed wall abutment chase lines leading to displacement of the seal and ultimately flashing detail. Strong winds and driving rain will aggravate this fault.
Can I claim on insurance?
In most cases, yes it should be possible – there are 3 types of insurance:
Building Insurance
Building insurance covers the property itself and would cover damage caused by a leak in your flat roof.
Contents Insurance
Contents insurance protects the items (e.g. computers, furniture, etc.).
Combined Buildings & Contents Insurance
This covers both building and content insurance in a single package.
Flat Roof Insurance
Insurance provided by a flat roof installer should cover materials and workmanship and also offer an insurance backed guarantee (e.g., Independent Warranty Association (IWA))
If you have recently moved house or are planning to, contact your insurance company to ensure your roof is covered. A flat roof survey should be able to assess the condition of your roof and identify any issues.
Next steps… deciding on a repair strategy
Deciding how to repair your leaking flat roof can be selected from a few options that include complete removal and new construction, directly overcoating the existing roof with the glass fibre installation, or the subject of this article, by over-decking the existing substrate…..namely an overdeck installation.
It should be mentioned that this is not a compromised specification but a highly suitable method of taking advantage of a still sound original installation.
The benefits of such an installation are numerous …lower cost, less disruption and a speedier turn around which assists when considering the possibility of adverse weather elements.
Obviously this option is only appropriate following a detailed survey to assess the suitability of the existing substrate to receive this procedure. Quite often a core sample is required for example.
If the existing roof surface is spongy underfoot, sagging between joist lines, has been constructed from chipboard or evidence of decayed timber substrate including joists then this method is unsuitable.
If the existing roof is found to be suitable, then the general following procedure representing the required scope of works for a Strandek ‘Overdeck’ Installation can be approved as follows:
- Identify the position of existing joists and mark out. The majority of new fixings will be penetrating the joists and not just the remaining substrate base board.
- Prepare the existing roof surface as necessary depending on the surface type…eg., a felt roof may have clippings, blisters in which case sweep clear and slice out the blisters.
- Mechanically fix new 18 mm OSB3 8×2 interlocking Sterling Board to the entire prepared surface using 21 fixings per board and penetrating into joists. This will ensure a very solid roof deck with little to no movement at joints.
- Mechanically fix the appropriate pre-moulded edge trim to all perimeters and any upstand trims against wall abutments.
- Now begin the process of installing the Strandek fibreglass laminate in the manner described by your supplier or, allow the Strandek supplier to install for you…which of course receives a fully Insured Guarantee regulated by the FCA.
This procedure can be applied either by Strandek flat roofing or undertaken by yourself. If you are looking for a professional roofer, be sure to confirm the following:
- Accreditations: Construction Line, CHAS are industry-recognised certifications requiring a high degree of health and safety experience to achieve.
- Excellent feedback: customers should be prepared to leave genuine reviews after roofing work has been performed.
- Guarantees: system, workmanshiop and insurer backed guarantees.
- Proven performance: high quality roofers should be able to comfortably demonstrate the quality of their workmanship
- Cheap: sound too good to be true? It probaby is – generally if a roofer is quoting you a roof that’s very cheap, it probably won’t last very long!