Sunday, February 15, 2015

Inspecting Roof Spaces – Part 2 - A Surveyor's Aladdin's Cave

Roof spaces are not always the nicest environments to inspect as space can often be restricted, they can be cluttered, poorly lit, poorly ventilated, dusty and contain a whole host of different hazards.  Having said this, an inspection would be sadly lacking if a visit to the roof space was not undertaken

In last week’s article (Link) I explained how the inspection of the roof space in a building can help to identify much about a building’s construction and condition as the ‘bare bones’ of the building are often exposed.  Roof spaces are not always the nicest environments to inspect as space can often be restricted, they can be cluttered, poorly lit, poorly ventilated, dusty and contain a whole host of different hazards.  Having said this, an inspection would be sadly lacking if a visit to the roof space was not undertaken. An inspection of roof timbers within a domestic roof space is fundamentally important due to the amount of timber that is used and the many ways it can be affected.  This was something that was discussed in last week’s article however there are many other things that a surveyor will inspect within a roof space that can prove to be equally significant.

Ventilation – Roof spaces should be appropriately ventilated, with a good flow of ventilation adequately maintained to reduce the effects of condensation and is essential to comply with Building Regulations and British Standards. Ventilation openings should be designed to prevent the ingress of rain, snow, birds and large insects.  Building Regulations Approved Document C2 requires that roofs are designed and constructed so that their structural and thermal performance are not adversely affected by interstitial condensation (condensation that occurs within the building fabric).  A surveyor will check for adequate roof ventilation and inspect the roof eaves as well as vented roof tile and ridge ventilation to ensure that there is a good cross flow of air.  Sometimes the surveyor will find that quilted rolled insulation has been tucked tightly into the eaves, blocking the ventilation.  Whilst this may keep the internal roof space a little warmer it will actually have a greater detrimental effect by creating an environment for condensation which can result in high concentrations of water which permeate into the internal environment of the roof space.

Insulation – There has been a great deal of publicity over many years, backed up with a number of funded government initiatives making the public aware of the benefits of insulating their roof spaces.  Despite this it never failed to surprise me of then amount of roof spaces that I inspected where I found insufficient or in fact no insulation at all.  The Energy Saving Trust identify that ‘in an uninsulated home, a quarter of heat is lost through the roof’. Other research can be found which suggests that heat loss through the roof in closer to 40% in an uninsulated home. In any event, with the cost of energy nowadays it makes sense to ensure that a roof space is adequately insulated.  A surveyor will inspect the condition, type and adequacy of any insulation that is present.  The requirements for the conservation of fuel and power, which includes thermal insulation, in buildings in England are detailed in Approved Documents (AD) L1A, L1B, L2A and L2B to the Building Regulations 2013 which came into effect on 6th April 2014. The current recommended depth of blanket style insulation (glass or mineral wool) for a roof space is approximately 270mm, however manufacturer’s instructions should be reviewed to confirm that the appropriate ‘u’ values (a measure of heat loss in a building element) are being achieved.

Vermin (and other 'species') – To us humans a roof space can be a drafty uninviting environment, however for other ‘species’ a roof space can provide a nice secure and warm habitat.  It is for this reason that squirrels, mice, pigeons and other birds (including bats), wasps and others together with a vast array of insects, find their way into a roof space.  Removing/dealing with some of these species is not as easy as you would think as a number of these ‘species’ are protected under UK Laws such as the Conservation of Habitats and Species Regulations 2010 and the Wildlife and Countryside Act 1981.  A surveyor inspecting a roof space may actually see ‘live examples’ however in most cases it will be the evidence left behind such as droppings or damage in the roof space that indicates their presence.  A clue to historical vermin problems will be evidence of mouse traps and other pest control measures.  The surveyor will also inspect a roof space looking for points of entry which may warrant urgent attention.  Insects are less easy to manage, mainly due to their size and due to the fact they often find their way into a roof space through ventilation points, which should not be blocked up for the reasons discussed above.

Fire Separation – In the event of a fire it is imperative that the construction of a building does not allow smoke and fire to migrate from one property to another.  Below the roof space this is achieved with the construction of fire resistant walls which in most cases (in the UK) use masonry materials such as bricks and blocks which are finished with plaster.  However It is essential that this fire separation continues into the roof space.  I have undertaken numerous inspections over the years where I have found that the party wall in the roof space is either partially constructed, or in some cases, in older buildings, there is not fire separation at all! A surveyor will pay particular attention to this detail and where there is fire separation present, check it’s condition and integrity.

Security - Where a party wall in the roof space is either partially constructed or maybe not present at all, it is also worth thinking about security.  I can remember inspecting a property some years ago which was next door to a property that had been empty for many years to a point where it was derelict.  The owner of the property I was inspecting told me that a few months earlier, their property had been burgled where access had been gained from next door’s roof space into their own roof space and into the property through the access hatch.  This was possible because at the time, the party wall was only partially constructed.

Water Storage – Although not so common nowadays with the introduction of mains fed boilers, roof spaces will still contain water storage tanks, which were used for gravity fed water systems.  A rising main would supply water to the storage tank which via a ball valve would refill as the water was used.  Many water storage tanks have now been removed however where they are present the surveyor will consider a number of different things during an inspection.  Due to the weight of a fully laden water storage tank a surveyor will look at the way in which it is supported as well as the condition of any supports (checking for timber decay etc.).  Also, asbestos containing materials were commonly used for water storage tanks so the surveyor will identify if this is the case together with its condition.

Where water tanks are present but have become redundant due to the installation of modern systems, they may still contain or they may have been partially drained. This could provide an environment for legionella. (Link) describe as;
‘Legionella bacteria is commonly found in water. The bacteria multiply where temperatures are between 20-45°C and nutrients are available. The bacteria are dormant below 20°C and do not survive above 60°C.
Legionnaires’ disease is a potentially fatal type of pneumonia, contracted by inhaling airborne water droplets containing viable Legionella bacteria. Such droplets can be created, for example, by: hot and cold water outlets; atomisers; wet air conditioning plant; and whirlpool or hydrotherapy baths. Anyone can develop Legionnaires’ disease, but the elderly, smokers, alcoholics and those with cancer, diabetes or chronic respiratory or kidney disease are at more risk’.
Where an environment exists where a surveyor suspects that legionella could exist then a specialist will be recommended to undertake a legionella risk assessment and to carry out testing.
This and last week’s article have identified why it is so important to inspect a roof space in a property and the many things that can be found, that will not be possible in other parts of the building.  The items discussed are not exhaustive however those selected represent some of the common typical things that a surveyor will look for when undertaking an inspection.

For completeness and in relation to health & safety, I will repeat what I stated at the end of last week’s article:  ‘Before inspecting a roof space it first worth expressing a note of caution.  Firstly, many roof spaces are accessible with a ladder only and will not have any lighting, so a torch will be required. Also, before entering a roof space always make sure that the environment is safe for you to do so.  Fragile materials, dust, noxious fumes, vermin and live services are some examples of the types of hazards that may be encountered, so if you have any doubts at all about your own health & safety then you should not enter a roof space.  In any event it would always be appropriate to instruct a professional such as a Chartered Building Surveyor to carry out the inspection for you, who will provide you with a comprehensive report, highlighting all issues within the roof void’

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