Most of us only have to think about replacing a roof once in our lifetimes and in many cases it’s something that never occurs. However, the cost of re-roofing or replacing a roof is significant and it pays to understand a few of the basic facts about roofing before picking up the phone and asking for quotes! Here’s the low-down on the basics of roof construction.
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Basic Roof Facts
Traditionally a roof has one main purpose – to keep the weather out. Today, with increasingly high energy bills plaguing most of us, roofs also perform an important secondary function of keeping things in – particularly heat. This second function is something that you should consider closely when having a roof repaired, replaced or built from scratch. There are two main types of roof – the pitched and the flat. Both have been utilised throughout history, although the latter has had something of a bad press in the last century. Properly constructed flat roofs are, in fact, no less effective than their pitched cousins and they are also cheaper to build and far easier to maintain. Palaces and cathedrals across the UK feature large expanses of flat roofing – simply because it is a cheaper method of building. However, mass building programmes in the twentieth century, with cheap and cheerful materials (and building practices) have contributed to the less than favoured view many people hold of the flatter roof.
Flat roofs are constructed (or should be) with a slight pitch to them; anything with less than fifteen degrees angle is generally classed as a flat roof. This pitch is required to allow water to drain away into gutters. For this reason specialist firms, like Marcus Roofing should always be employed to repair or build flat roofs. In general a flat roof consists of several layers; the coverings include rubber roofing, felt or fibre glass. Below this comes thermal insulation, a vapour barrier, decking, joists and finally plasterboard. In some older roofs the insulation layer may be directly above the ceiling, leaving a cold gap between it and the top layers. Modern roofs normally have insulation close to the top layer to create better energy efficiency and reduce heat loss. Flat roofs are far cheaper to build, or repair and if properly maintained and constructed with modern materials they’ll compete well with a pitched variety. For some homes, they can also provide valuable extra outdoor space and for this reason, if you are faced with a choice between repair and replacement it can make sense to retain the flat version.
Pitched roofs are generally classed as anything with an angle over fifteen degrees; they can be pitched at a range of angles although forty to fifty degrees is the most common. Roof coverings vary from thatch to tiles or slate, although some type of tile is the most common. The most common designs for a pitched roof are gabled and hipped – in the former the two pitched slopes are supported on the gables of the building, while in the latter four sloping surfaces meet together. In most existing houses the loft space will be insulated directly above the ceiling (i.e. on the floor of the loft space). This is known as a ‘cold roof’, while insulation placed between the joist of the roof creates a ‘warm roof’. If you are replacing a pitched roof, the opportunity to add space to your home in the form of an attic room is one to consider and this will also mean insulating to create a warm roof.
Depending on the type of roof that you are planning to restore or replace you’ll need to consider the type of builders you’ll need. Most building firms will be happy to replace a pitched roof and should have the expertise to do so. However, when it comes to flat roofing a specialist firm is essential. As mentioned above, flat roofs don’t really deserve their poor reputation but they do need to be properly constructed in the first place. A firm with a history of specialising in this type of work is essential and will help to construct a sound and waterproof flat roof. The same will also apply to less standard forms of roofing – a thatched roof will certainly require specialists to complete the work. While it’s not a common domestic task, if it becomes necessary replacing a roof should not be a nightmare. It should also with the right professionals only be a once in a lifetime event!