Sunday, October 21
DIY

A-Z guide to roofing

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Our in-house handyman, Handy Mac, aka Don MacAlister, has compiled an A-to-Z guide to roofs and roofing, a topic which is often something of a mystery to ordinary householders.

Handy Mac gives advice on an integral part of any home – its covering

Attic Conversion More commonly known as a room in a roof, only undertake this project with proper planning and design. There are too many cowboys out there who will happily say “yes, no problem” and cut half your roof timbers away. Before any alterations are undertaken you must obtain a plan signed off by a structural engineer.

Box gutters If possible, avoid at all costs. A box gutter lies under the join of two roofs with water flowing in from both sides, or sits hard up against a parapet wall. The problem is they tend to be used in hard-to-reach places and so are tricky to clear. This means they often get blocked and overflow into the house below. In my opinion they are a disaster waiting to happen. Even Mrs Mac has learned: when she wanted us to move, she checked first and never took me to look at a house with box gutters.

Clay Still the best material for roof tiles, as long as the pitch is correct. Go into any old house with clay tiles and you will never find an underlay. Back in the day, roofs were constructed properly. Clay tiles are once again being imported into the country and they come complete with genuine high-class German design – a bit pricey, but worth every cent.

Dormers To me, these fall into the same category as attic conversions and box gutters. You are forming a small area that is going to be fraught with problems from day one. Unless included in the planning stage and part of the original roof design, you are going to be cutting and moving structural roof timbers – and paying a high price.

Eaves These form the bottom of the roof that overhangs a wall – an exterior ceiling for want of a better description. They can be closed, in which case a weather-resistant material such as Nutec must be used, or open with timber slats. This helps ventilate the ceiling/roof void to the main house but creates a large maintenance item.

Facias These are fixed at the end of the roof trusses to carry the gutters. For years timber has been used, but this is a high-maintenance material and can rot quite quickly as in winter there is a lot of water around. Nowadays we see them being replaced with Nutec (fibre-reinforced cement) or PVC, but to my mind they do not have the same aesthetics as timber.

Gutters The channels at the end of the roof take the rain water away. We have moved from cast-iron to asbestos, now Nutec, through PVC to aluminium and if you really want to look smart and successful, copper (very expensive). PVC is the cheap go-to option, but in my opinion, you can’t beat seamless aluminium – long single lengths with no joints.

Hips A hipped roof is one where all the sides slope downwards to the walls, usually with a fairly gentle slope. A hipped roof is pleasing to the eye, but is a lot more expensive to construct than a gable-to-gable roof and you will pick up leaks as the cement between the tiles breaks down over the years.

Insulation I am often asked about the best insulation to use in your roof void. It really depends on your roof covering and the design of the roof and ceilings. There are many great products on the market and you need to check their thermal insulation values. I don’t like foil-type insulation under cement tiles – if it is not installed 100% properly your roof is always going to rustle.

Joist A joist can best be described as the piece of timber running between the ends of your truss rafters. It will sit on the wall and stop the truss from deflecting outwards, it is also used to carry the ceiling or, if you decide to go for an attic room, it would carry the flooring.

Knot There are few “Ks” in the roofing world. Knots in timber affect cracking and warping, ease in working, and cleavability. They are defects which weaken timber and lower its value for structural purposes where strength is an important consideration.

Lead Lead was once used for flashings, sealing between vertical and flat surfaces because it is soft and malleable. Of course, the biggest factor has become the cost, as lead is far too expensive to use and also attracts thieves. We often get called out to inspect leaking roofs only to find someone has stolen the lead.

Moss This looks beautiful in shaded corners on stones in your garden, but is not so great for your roof. It grows where the sun doesn’t shine and eventually blocks the drainage channels in roof tiles. Not everyone agrees, but once moss has taken over your roof, I believe it is best to leave it until the roof finally collapses. Trying to clean it off an old roof just leads to further damage.

Nail There are many different types of nails made from different materials and, like everything else today, they keep being made cheaper and thinner. It is important that you use a nail that is fit for purpose. Do your homework on using the right one, especially if you are building something structural.

Opening We all love to form openings to change the look of things or to let in more light. Unfortunately, too many people merrily go ahead and cut away brickwork or timber without checking if the result is going to be structurally sound. Never cut any timber out of a roof without checking with a structural engineer.

Parapet Mrs Mac knows what a parapet is. For years she would drag me round to look at houses, but eventually caught on that I was never going to buy a house with lots of parapets. I hate them, they crack and let water in and at every intersection with any type of roof covering you have to have flashings which require major maintenance.

Quality A forgotten term as we all go in search of the cheapest price. You will never get decent quality if you pay peanuts, whether it be for materials or labour. Don’t let yourself be ripped off; take time to compare quotations to ensure that you are getting like for like.

Rust Modern materials and new-age technology have lessened the chances of roof sheeting rusting, but homes close to the sea will still be susceptible because of the salty air. Make sure you use the correct material for your climatic conditions and the secret of longevity is regular maintenance.

Homes close to the sea are susceptible to rust because of the salty air. Picture: Supplied

Slate This is the most attractive of all the roof coverings but seldom used anymore on new buildings because of cost. It also comes with the problem of keeping a roof watertight as, when used on a low pitch, malthoid has to be placed between the rows of slate and the malthoid deteriorates with age and exposure to ultraviolet rays.

Tiles Roof tiles are mostly manufactured from cement at the moment with clay making a bit of a comeback, but from a cost point of view sheeting will remain cheaper, mainly because of the lighter truss design required. From a cost versus aesthetic point of view I would still go with cement tiles though, which probably have a bit of a longer life span.

Underlays This is another product that has developed over the years. The days of plastic becoming brittle and falling down on the ceilings are long gone, and fabric-type tile underlays are now being used. With other types of roofing you need to ensure that you are not going to create a situation where condensation forms and starts to drip down causing damage. Ventilation is very important.

Valley A roof valley is the internal angle formed by the intersection of two sloping roof planes to provide water run-off. This weak spot on your roof directs large amounts of water into the gutters and is a common source of leaks. Proper maintenance is the key here; leaves and other debris build up quickly causing overflowing and rust.

Weather board This is a long thin board with one edge thicker than the other, used as side cladding by fixing one board over the board below. It is an attractive finish on gable ends. Boards can be timber, fibre-cement or PVC.

X-asperated What we all are at this time of year waiting for the roof repair company to arrive because we forgot to have the roof repaired when we had time and the weather was good.

Year The absolute maximum length of time between checking all the elements of your roof to ensure that they are well maintained. Remember a few rand spent now can save you a bucketload of money further down the line.

Zincalume This is steel that is dipped in a zinc-based product to give it a protective coating. A new-age roofing material that comes in a wide range of colours and profiles, it is resistant to corrosion and the elements.

*Handy Mac, aka Don MacAlister, is our expert on household DIY issues. If you have a question for him, please send it to don@macalister.co.za or SMS only to 082 446 3859. Find Don on FB: facebook.com/thehandymac

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