All pitfalls of laying a new roof on top of the old (ondulin)

Many builders have already appreciated the benefits of ondulin, which is also called euro slate. Among the advantages note a smooth coating on which dirt does not linger, noiselessness and durability. Many people think that in order to independently lay the roof of ondulin on top of the old one, it is enough to simply follow the instructions drawn up by the manufacturer. However, even the most detailed recommendations cannot take into account some of the subtleties that arise in the installation campaign.

Even at the preparation stage, it is necessary to purchase additional elements - this is the ridge, tongs, end plate, cornice, covering apron, insulation tape and filler cornices. It is also necessary to decide in advance whether the roof under the onduline will be warm or cold. If you choose a warm option, you need to take care of installing a vapor barrier. If the roof remains cold, then natural ventilation will be sufficient. To choose the right number of sheets, you need to take into account not only the dimensions of the products, but also the so-called usable area, which may differ from different manufacturers. As for the fastening of the sheets of ondulin, the special nails are considered the most common, which have special wide hats that securely fix the sheets on the crate.

But besides this, there may be options with fastening in the form of special brackets and mounting foam. Experts advise not to refuse such an option, because similar fasteners are used when installing piece natural tiles.

All this fully applies to the installation of a new roof on top of the old. Many homeowners are happy to save time and energy that could be spent on disassembling the old roof, garbage collection and other work. In addition, the second layer of the roof provides double protection against leaks. However, when working, do not be lazy and, first of all, be sure to clean the old roof from debris and dirt. It is necessary to carefully inspect the supporting structure, if necessary, replace or remove fragments of the old roof, to renew the supporting elements if they rotted or cracked in places. If there is a metal skate, it must be removed. After such preparation, you need to fill the rails along the rafters for fastening the ondulin, then install the crate with the same interval as with standard installation. Here, the instructions from the manufacturer will help in the calculations. About 10 cm from the ridge to the ramp, you need to put additional parts of the crate, a new ridge will be attached to them. After laying the sheets according to the classical scheme, it remains only to put a drain and a drip on the cornice. If for some reason there are several extra sheets left, you can block them with the roof gables.

In general, the installation of an ondulin roof over the old one differs from the standard installation by the preparation of the old coating, the replacement of shabby sections and the dismantling of the old ridge. Otherwise, you must adhere to the usual rules for working with ondulin. The required overlap is calculated depending on the manufacturer according to the instructions. You also need to remember that you need to work with this material only at positive temperature. If it is within -5C, take extra care. If the temperature is even lower, it is better to refuse work. The same applies to too hot weather, when the thermometer reaches more than 30 degrees.