Understanding how your roof is put together
Your roof is such a large part of your home, yet chances are you don’t give it more than a cursory glance every now and then. But when you roof has an issue, it can have a major impact on your life. So understanding a little bit about how your roof is put together could help you identify problem before they turn into catastrophes.
To help you appreciate the structure of your roof better, we’ve put together a simple guide.
Read on and enjoy!
Your Roof’s Purpose
In a nutshell, your roof is there to protect everything that is beneath it, keeping you safe from the elements and the environment. Not only that, it prevents unwanted guests from entering your property, while playing an important role in the energy efficiency of your building.
Types of Roof
The type of roof depends on architectural design and personal preference, as well as environment aspects. There are two main types:
- Flat – with an angle of 0° to 15°, but most have an angle over 0° to allow for water run-off
- Pitched – with an angle of 15° to 70°, although generally most fall within 40-50°.
Basic Roof Design
Most pitched roofs are based on three main designs:
- Gable – 2 sloping sides that meet at the top, built around a triangular end wall
- Hip – the joint between two or more adjacent slopes. The end wall does not extend up, as with a gabled end roof
- Shed – only one slope, such as seen on a lean-to construction
Complex designs can include various aspects of both.
Pitched Roof Construction
The majority of roofs are pitched, and are first constructed by building the frame, which is the main support. Trussed frames are common. Four main elements are then built on top:
- Wooden joists, or rafters, which support the weight of the roof
- Breathable membrane (or felt in older properties). This protects the house from the elements when the roof is being constructed, and offers a secondary layer of protection on completion. It’s held onto the joists by nails
- Wooden battens are nailed onto the joists over the membrane, at right-angles
- The finishing waterproofing layer, which is generally slate, clay or concrete tiles, are attached to the battens.
Roofing Terminology
Other aspects of your roof include:
- The eaves – the area where the tiles meet the gutter
- The ridge – the meeting point of the sides of the roof
- Ridge tiles – used to cover the gap at the ridge, and either fixed with mortar or a dry system can be used. There are various designs, which can be selected to complement your property
- Hip tiles – used on hip roofs on the ridge, although ridge tiles can be used as well
- Valley – if two roofs join together you may get a valley, which is lined with lead or a specialist valley tile or a GRP strip
- Rakes – the outer edge that runs from ridge to eaves
- Soffits – fixed at right-angles to the fascia, this board is seen when you look directly up
- Fascias – fixed directly to the roof trusses, the fascia runs all along the edge of the roof. It supports the guttering and last row of tiles
- Bargeboards – used on the gable end, it provides an attractive finish to the roof, contributing to the overall look
- Boxend – this is the meeting point of the soffit, fascia and bargeboard, and needs to be finished attractively for the overall effect to be pleasing
- Verges – the area where the gable end meets the edge. Tiles need to be fixed down, usually with mortar, to prevent the weather entering underneath
- Lead flashing – used to seal joins on roofs
Other Roof Considerations
The inside of your roof is usually insulated, and there are two main methods of doing this:
- Warm roof – the insulation is laid between roof and rafters and keeps the warmth in the roof. This is great for attic conversions
- Cod roof – insulation is laid above the ceiling to keep the heat in the house; this is generally more common.
Your roof also needs ventilation, to get rid of heat and moisture. If left to build up, it can cause damage to the roof structure, leading to mildew and mould. Vents can be built into the gable end or directly into the roof, or sometimes along the ridge.
And Finally
Next time you look up at your roof, think about the structure that goes on underneath, and all the aspects that make up the finished product. The more you know about your roof, the easier you’ll find it to identify areas that need attention, saving you both time and money.