Monday, February 9, 2015

Inspecting Roof Spaces – Part 1 - A 'Rafter' information available

Anyone with an interest in property can learn a great deal from what they find in a roof space as this is one of those places where most people chose to ignore, use is generally limited to storage or access once a year to collect the Christmas tree and then put it back again afterwards!

One of the great things about of being a Building Surveyor, is that we get to crawl around and inspect numerous parts of a building that many others would often not dare to venture.  Basements, floor voids, manholes are good examples, however a common place that will tells us a great deal about a building is the roof space (or attic depending on which part of the World you are from).  It is true that some people choose to utilize the roof space to maximize the habitable space as well maximizing the potential of their property and decide to refurbish the area, covering all of the exposed details in the process.  However when we access a roof void which has not been adapted or refurbished we enter a ‘mine' of information because it often allows us to see a building in its barest form.  Anyone with an interest in a property can learn a great deal from what they find in a roof space as this is one of those places where most people chose to ignore, use is generally limited to storage or access once a year to collect the Christmas tree and then put it back again afterwards!

There are a number of different roof types that can be selected depending on design criteria, aesthetics, location and ultimately costs, however for the purposes of this article I will refer to a traditional timber pitched roof, typically found on domestic dwellings in the United Kingdom, United States and other parts of the World.  Certain parts of the World that do not experience excessive rainfall may favour a flat roof, however where there is regular rain and snow a pitched roof will allow more efficient rainwater run-off, as long as the roof is constructed and maintained to a good standard. 

Pitched roofs can either be ‘cut and constructed’ on site or alternatively trusses can be manufactured off site, delivered and installed as a complete component.  Either way both choices ensure that a large amount of timber is installed and concealed with the roof void when a building is completed.  All of this timber has the potential to deteriorate/decay for a whole host of reasons and must be inspected on a regular basis to monitor its condition.  Although inspection of the roof timbers is important, the Inspection of a roof space includes much more than just this. The remaining part of this article will provide some examples of what a Surveyor will look for when inspecting timbers in a roof space and next week in Part 2 I will discuss other things that a Surveyor will consider.

Roof timbers – There are many different components of a timber cut roof, for which each has its own purpose and function.  A Surveyor will inspect all of the roof timbers carefully looking for signs of damage, deflection, dampness and water presence or possibly decay (wet rot or dry rot), or even woodworm.  Clearly there is a great deal that can affect timber and with it, its ability to maintain the function it was designed for.  The Surveyor will inspect the underside of the roof surface for any indication of water ingress, condensation or possible signs of daylight. This should identify if there are any missing or displaced tiles and where the sarking felt is split or missing. 

One of the primary functions of a roof is to keep the internal environment dry and it is essential that water is kept away from the timber.  In the event that water does come into contact with timber then an environment for wet rot or possibly dry rot may be created if left undetected.  Wet rot requires timber with a very high moisture content (typically 50% to 60%) in order to thrive, so any timber effected by wet rot in a roof void would need to be exposed to moisture over a long period of time. Dry rot requires a lower moisture content than wet rot (typically 25% to 30%), but also prefers much more humid temperature.  In both cases, poor ventilation is also usually a factor. You can read my previous article on dry rot by using the following (Link).

When inspecting for woodworm the Surveyor will look closely at the timber for ‘flight holes’ these are identifiable as little pin holes. Damage occurs to timber as a result of the larva boring through the wood with the eventual appearance of the adult insect. Different insects have a range of life spans, different flight hole sizes and are active at different times of the year.  In order to try to establish whether there is evidence of recent activity the Surveyor will look for small piles of dust (known as frass) on surfaces adjacent to the flight holes.  The Surveyor will also inspect the timber with a bradawl (similar to a blunt edge screwdriver), to establish the extent and depth of any woodworm attack, by ‘prodding’ the timber at various locations. For completeness woodworm is defined Timberwise (online) as; ‘Woodworm is a generic term that is used to commonly describe the larvae stage of all wood boring beetles. The most common beetle in the UK is known as the Common Furniture Beetle, however there are various other beetles which can make a nuisance of themselves. Other types include Powder Post Beetle, Wood Boring Weevil, Death Watch Beetle and House Longhorn Beetle’ 

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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