When deciding whether to inspect your roof, do a repair, or walk on your roof for any other reason, there are several steps you can take to ensure your safety. These safety procedures are often overlooked, causing accidents that can affect a person and their family for years to come. However, if you invest just a small amount of time in the Woodlawn Lake area educating yourself of the potential dangers of your roof, you may avoid these incidents all together.
Homeowners seldom think about the roof over their heads until they encounter a roof leak problem. Then the question always comes up: should they get a tear-off (roof replacement) or just get a shingle overlay that just covers over the old roofing? A roof is comprised of four elements: the main roof, the eaves, the fascia board and the gutter. A house without eaves can cause as much water damage as a house without a roof
Roof valleys are a frequent source of leaks in older houses. Installation procedures differ depending on the roof type and materials used. We will look here at the basic installation of an open lead lined roof valley.
A roof valley is basically a gutter set between two meeting pitched roofs. Depending on the roof area it serves, the valley is the exit point for a large volume of water so extreme care should be taken with installation. If the roof has been leaking for a while or if there are any signs of rot, you will need to start by replacing the valley boards. Lead sheet is not self supporting and should be placed on treated roofing boards of sufficient strength to hold a large person. (Most roofing contractors are big guys!) Fit boards of sufficient width to accommodate the lead plus 100mm either side. This will give you something to nail the roofing batons to.
The top of the valley boards should be at the same level as the top of the roof rafters. If you lay the boards directly on top of the rafters it may cause the roofing tiles to kick up and restrict water run off. You will need to cut the valley boards to fit in between the rafters. Support the valley boards with studs or noggins. The valley should finish on an even plane at the eaves. It should not kick up higher than the bottom rafters. If it does, you will need to cut the fascia board or adjust the gutter to suit. It is a good idea to fit a tilting fillet each side of the valley. This angled strip of wood runs along the valley length and should be a minimum of 150mm from the centre of the valley. It should sit no higher than the roofing batons with the thinnest end closest to the centre of the valley.
It is common practice to fit a single sheet of roofing underlay the entire length of the valley. The adjacent roofing underlay will rest on top of this sheet. I recommend you use one of the new advanced synthetic underlay materials. The older bitumen based felts are fine for normal roofing situations but are not suitable for valleys. Over time the bitumen will bond the lead to the boards and restrict thermal movement. You should ensure you buy lead of a sufficient grade/code for valley applications. This should be between 1.80mm and 2.24mm thickness. If you are unsure ask your roofing merchant of the correct grade. The lead should be cut into sections no larger than 1.5 meters in length to allow sufficient thermal movement. Bend a welt into the lead 25mm each side. This acts as a last line of defence for water penetration. It also has the added benefit of stiffening the lead, which makes carrying it up the roof a lot easier.
Starting at the bottom of the valley, dress the lead neatly onto the valley boards and over the tilting fillets. The bottom of the lead should allow correct drainage into the gutter. Fix two rows of nails at the very top of the flashing. Use copper or stainless steel nails. Never use galvanised or aluminum nails which will just react with the lead and corrode. I recommend you use the minimum amount of fixing possible to hold the lead in place. If you over fix lead sheeting it will eventually split due to thermal movement. So don't nail the sides. When you have successfully dressed the first sheet you can move up the roof laying subsequent sheets. Overlap each sheet a minimum of 150mm. On lower pitched roof valleys you will need to increase the lap. Where the valley ends at the ridge, you will need to dress the lead so it can sit neatly under the ridge tiles. You are now ready to start fixing the batons and laying the roofing tiles. The key points to remember are to keep the sheet lengths down to 1.5 meters and don't over fix. If you follow the procedure outlined and take care with the dressing you will produce a durable maintenance free valley.
Corrugated Iron Roofing is durable, lightweight and easy to install. If a few extra precautions are taken with handling and fixing, the finished product will greatly be improved.
Over half of the mistakes made while constructing a corrugated iron roof can be traced back to incorrect storage or handling. The iron has to be handled and stored correctly because the surface is very easily damaged.
Leave the metal roofing at the manufacturers until you are ready to start installing it. Aim for delivery the day before roofing starts. If the roofing iron arrives before you are able to fix it, you must ensure it is kept bone dry. It is a common mistake to assume that because they are roofing sheets, they can withstand moisture. If the roofing sheets are stacked together and they get wet, they will stain. White rust forms on the coating and it is very difficult to remove. If your roof sheets do get wet, separate each individual sheet. Use bearers to allow airflow around the metal. This will prevent the corrosion.
Gently does it
As for handling, care needs to be taken in order not to damage the paintwork. Sliding sheets across one another will damage them. When separating the roofing sheets, you should lift them cleanly upwards without scratching the one underneath.
Laying the roofing
Before you start laying the roofing sheets check that the roof is square. If the roof is not square you can still achieve a good finish if you even out the difference, between the two barges. The difference will then be less noticeable as it will be covered by the barge flashing. Run a string line along the eaves, 50mm into the gutter and it will provide you with a straight edge for the roofing sheets.
On completion it's important to clear the roof of any loose swarf. Tiny particles of iron left on the roof will rust and ruin the surface. A soft brush will do the job or ideally a leaf blower can be used.
A well installed corrugated iron roof will give years of maintenance free service. If you take a little extra care with the preparation and fixing, you will achieve a superior finish.