from RICS Home Survey reports





To surveyors, roof spaces are treasure troves brimming with clues to the health of a building. Even in heavily modernised properties the refurbishment work rarely extends as far as the loft because prospective buyers tend to regard this as dead space.  As well as providing valuable pointers to a building’s age and type of construction, time spent up top can expose illicit structural alterations, pinpoint leaks and defects, and provide useful information about the property’s thermal performance.

Given that the roof and the space inside it are two sides of the same coin, it may seem counter-intuitive that in survey reports they are covered as separate topics, with ‘roof structures’ normally appearing several pages after you’ve finished reading about ‘main roofs’. This is simply down to convention which dictates that the exterior parts of the building are presented first, followed by the interior, the services and the grounds.


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 Things to check


1/   Structural defects and alterations

Based on experience, surveyors will be familiar with different types of roof structure, so alarm bells should ring loudly if any bits are missing!  Common botched alterations include the misguided cutting away of supporting struts, collars or hangers to make more space, and the removal of chimney breasts in bedrooms without providing proper support to the remaining masonry in the loft above. In period timber frame houses projecting bracing timbers are sometimes spirited away in a bid to improve headroom. Shocking acts of vandalism are sometimes perpetrated in modern trussed rafter roofs, with the ‘W’ shaped webbing hacked out to make way for illicit ‘loft conversions’ – or to accommodate cannabis farms!

Of course not all structural defects also are due to botching. For example ‘roof spread’ can occur where the rafters have pushed out the upper walls because they’re not restrained by ceiling joists. Movement to the main walls below may be the root problem, or persistent dampness can result in localised timber decay. Common less serious concerns include the lack of  ‘lateral bracing’ early trussed rafter roofs (c 1970s) which bolsters the trusses against the risk of leaning, racking and buckling.

The cost of rectifying the problem will depend on the extent of the damage, but works such as providing localised strengthening to part of a structure needn’t be a major undertaking. Although there may be no signs of movement, without proof that Building Regulations consent was obtained for structural alterations, the surveyor can’t be certain that the structure was adequately supported. This needs to be addressed when buying property to renovate otherwise it will simply resurface when you come to sell and can be a potential deal breaker. Applying for retrospective Building Regulations ‘regularisation’ is one solution, but will involve a certain amount of opening up of the structure.

Remedial work:   Rectifying botched structural alterations will require a structural engineer’s report and a fresh Building Regulations application. In simpler cases beefing up support with a few new timbers may be all that’s required, in severe cases partial rebuilding may be necessary. Unsupported chimney masonry normally requires the provision of a steel beam resting on load-bearing walls. At the other end of the spectrum, upgrading trussed rafter roofs with ‘lateral bracing’ simply requires fixing long timber battens horizontally and diagonally across the trussed rafters which should be fairly straightforward and inexpensive.


2/    General dampness in loft

Dampness that isn’t caused by roof leaks is often the result of condensation, or may sometimes be due to driving rain penetrating thin, cheaply constructed gable end walls. Evaporation from water tanks and leaks from pipes may compound the problem. Typical symptoms include damp loft insulation, roof timbers and ceilings. However, sagging or torn underfelt is not usually an issue if the roof coverings are in reasonable condition (replacement of underfelt is uneconomic unless the roof is due to be stripped).

Condensation is caused by warm, moist air filtering up into the loft and coming into contact with cold surfaces such as the roof tiles. Poorly fitted extractor ducting serving bathrooms below can pump huge amounts of water vapour into lofts. Without decent ventilation to expel this humid air before it can cause any damage, it can turn back into water, dripping onto the ceilings below.

Once surfaces become damp they will be colder and more prone to condensation, acting as ‘cold bridges’ that suck heat out of the building. And once insulation gets wet it becomes ineffective, losing the power to act as a thermal barrier. Sustained dampness in lofts over time can cause mould growth and rot to roof timbers, and decay to the wooden lathes which anchor the plaster in old ceilings.

Remedial work:  To deal with condensation, you need to limit the amount of moisture getting into the loft in the first place and also provide sufficient ventilation so that any humid air that does make it through is wafted safely away.


3/    Missing / substandard firebreak walls   

It’s not unusual in Victorian terraces to find that the original builders cut costs by omitting the party ‘firebreak’ walls. Even where party walls do exist, parts may be missing (often close to the underside of the roof covering) or they may only comprise thin single skin brickwork.

This is a potential killer, allowing fire to rapidly pass from one property to another, as well as being a security threat. There may also be implications with poor support for the roof timbers. Hence this is something that gets a red condition rating in surveys, requiring urgent action. Ignoring this advice is likely to lead to mortgage problems when selling a refurbished property. Before carrying out any works bear in mind that the adjoining owner(s) will have legal rights over this wall and the Party Wall Act will apply, so specialist advice is required. On the plus side, the neighbour may be willing to contribute to the cost since it will benefit them equally. Building Control should be notified before starting work.

Remedial work:  A new firebreak wall will need to be constructed, e.g. of single skin blockwork or studwork clad with pink (fire-resistant) plasterboard lining with a skim plaster finish. Small gaps can be pointed up or stuffed with fire-resistant material such as mineral wool quilt.


4/    Nests and vermin

Symptoms:  Smells, droppings, and straw in loft; damaged stored items; chewed electric cables and pipe lagging. Small wasps’ nests are particularly common.

Not usually a serious concern but in severe cases can cause short circuits or leaks (if plastic cables or pipes are chewed) and water tanks can become polluted. Eventually pests may spread to habitable rooms with potential hygiene implications for hygiene.

Remedial work:  Block easy access routes into the roof space via gaps at eaves, broken slates, open vents, climbing shrubs etc. Wire mesh can be fitted over any large holes so that loft ventilation is maintained.

Treatment of wasps’ nests isn’t too expensive, and can even be done on a DIY basis subject to taking appropriate precautions. Traps and bait can be used to deal with rodents, or a pest control contractor hired to do the job. Smoke treatments can be effective for eradicating insects, and high frequency sound devices are sometimes used to deter rodents. Note that bats are a legally protected species, so specialist advice should be sought.


N.B.  This is by no means an exhaustive list, and much depends on the age and type of property you’re surveying


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