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    Installing flat type roofing: all you need to know

    Flat roofs are incredibly popular, but the area in which you live may determine which materials should be used.  In hot climates where rainfall is much less frequent, for example, flat roofing is often constructed of brickwork or cement as it helps to deter hot temperatures, is inexpensive and easier to use when a wooden material is not easily accessible.

    On the other hand, in locations where the roof may become overloaded by rainfall and outflow, or where water drenched masonry could lead to frost and result in ‘blowing’ (the breaking up of cement, stonework, concrete through expansion) these types of roofs may not be suitable.

    The three types of flat roofs

    Flat roofing usually has a 10-20 year guarantee, but when flat roofing is a matter of concern, Findley Roofing proves to be the best choice. With professional installation, a roof can last for more than 20 years.

    Build-Up Roof (BUR)

    This hot-tar and stony roof is made from 3 or more layers of water-resistant material alternated with very hot-tar and ballasted with a layer that is associated with flat and smooth river stone. This type of roof uses more-advanced materials like membranes of fibreglass when made of tar paper.

    The benefits: The rocks are first-rate fire resistant and look striking with windows as well as decks, managing the overall roofing style. It is also the least expensive of all three roof types.

    Downside: This roof type is very heavy so often beams need to be strengthened. A built-up roof is not recommended for busy homes as it can smell and is untidy to install and there is no possibility of DIY installation as it is difficult to find leakage points. The tiny rocks and gravel used in installation can sometimes block gutters if a professional roofer is not used.

    Modified Bitumen

    This is a single-ply folded roof that is similar to ice-and-water protection shields but saturated with a mineral-based wear surface area. Modified bitumen roofs can be installed with the common torch method, asphalts or cold adhesives.

    Benefits: Peel-and-stick material can be set up by property owners, and it has a light coloured mineral surface area that reflects the temperature and slashes energy bills.

    Downside: The torch-down application method is dangerous and can cause a fire therefore not recommended for occupied structures or buildings.

    Rubber Membrane

    EPDM (Ethylene Propylene Diene Monomer) is a rubber that resembles a good inner pipe but is manufactured to resist harm from sunlight.  EPDM can be mechanically moored with nails, ballasted alongside stone or even glued.

    Benefits: Homeowners can easily install a rubber membrane roof because its material is comparatively light yet extremely resistant to scuffs, scratches, and holes. It is also incredibly simple to patch leaks.

    Downside: The standard dark material absorbs heat and light-coloured coverings which, in warm climates, can add thirty percent or more to the cost. It is more expensive than BUR or modified bitumen and more susceptible to punctures than the other types.

    Building a Flat Roof: The Steps

    Roof framing

    The first thing that you need to remember is a flat roof is not completely flat. A slope of at least 1/8 inch per feet is considered best, and if you are in a region where rainfall is more frequent, then a ¼ inch downward slope per feet is highly recommended. For example, if the total area is 5 metres with the ¼ inch rise (0.06M) per feet (0. 30M) then your total sum of the roofing length will be approximately 1 foot (0.30 meters). Between two assisting walls, frame your roof by using 2” x 4” or 2” x 6” beams. Fix nuts between the supports/joists for additional support.

    Plywood sheathing

    Now, shield the framework with 5/8 inch marine plywood leaving a 1/8 inch gap to build important joints. The expansion and compression of the plywood should be covered by this.

    Clear the plywood sheathing

    Clear the actual plywood sheathing from any kind of wreckage. The rubber sheathing that you intend to put on the flat roof could be ruptured or could have a hole due to a nail head or timber splinter.

    Rubber sheathing

    EPDM rubber sheathing is available in 10-foot broad rolls, and it is quite easy to cut the rubber sheathing into the required pieces. Measure the total finished region to be roofed and allow approximately 0.25 meters all over. If the width of the roof is more than 10 feet (3 metres), overlay the rubber sheathing with at least 6 inches (0.15 metres). Roll the rubber sheath back in half.

    Glue the rubber sheathing

    With the help of a paint roller, spread glue on the plywood and rubber sheathing. You can also overlap the plywood with ISO board ½ inch thick inflexible foam. For those who have this option, it is vital that the ISO board is glued to the 5/8 inch plywood before laying the rubber sheathing. Glue the rubber sheathing in a direction from the middle of the roof toward the edges. The glue should bond immediately.


    Once the glue has begun to dry, lay and tap the rubber sheathing on the plywood smoothly and avoid lifting any part of it to avoid crumpling on the rubber sheathing. If there is an outlet tube or pipe that protrudes through the roof, slice the rubber sheathing to create a hole that is larger than the pipe size and slither the rubber over the top of it. To avoid leakage, add a rubber collar to the pipe and fasten it over the rubber sheathing.

    Finishing the edges

    Caulk the interior corners through cutting and covering the rubber sheathing then paste the corners with glue. Fix the rubber sheathing on the walls vertically and, after that, use the tri-polymer seal to the nails to close them off. You can also fix a stony stopper (galvanized iron) flashing in the corners of the roof that help to make it more waterproof.

    Findley Roofing & Building is a leading installer that offers all required material and its expert services for the complete installation of flat roofing.

Need help? Call us today: 0191 417 3422