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How To Insulate A Metal Roof?

March 13, 2015 - Roof
How To Insulate A Metal Roof?

When it comes to metal roofing we must consider not only the outside, but also the inside, meaning the insulation system. This must be done, whether we want to or not. In this article you will learn about the steps and materials required to carry out the water and heat insulation for the roof of your house. Steam, precipitation and noise are present in any building.

If a house has an uninhabited attic, the roof is cold, that space allowing natural ventilation. Steam from the atmosphere enters and leaves through the holes provided in the original project. Even if your attic is inhabited or not, the water, the heat and the sound proof insulation is absolutely necessary. Through the roof 30% of the heat loss occurs. Moreover, having a humid environment in the attic, can cause damage to the roof wooden trusses, which can lead to the weakening of the building.

So let’s take a close look at the metal roof that’s on the house. This should be fully functional in any situation, when it rains torrentially, when the wind speed is impressive and when snow falls relentlessly. We must apply hydro and thermal insulation. This must be done all over the inside of the roof. We should not neglect even the slightest surface.

➤ What are the required materials for roof insulation?

Note that the order of application of the insulation is very important. The purpose of waterproofing is that moisture from the condensation of steam coming from the attic or accidental penetration of water can not reach the ceiling of the room below. Why? Because mold and dampness can occur.

The interior roof insulation materials required are: glass or quartz based mineral wool, for it’s diffusion properties of steam, aluminum foil or polyethylene for it’s vapor barrier role. Instead of mineral wool, extruded polystyrene or polyurethane foam can be used, but it is less effective. Attention, the insulation layer should not be closer than 3 cm from the roof, as it deteriorates very quickly in summertime when the air temperatures are very high.

➤ How to apply the layers of interior insulation of the roof?

First apply the layer of mineral wool or polystyrene, even between the rafters. If you use mineral wool, you must have the accessories required for mounting between the joists. A forced fit of the wool or polystyrene layers is recommended. Do not use expansion joints. Optionally you can install the second layer of insulation, over the rafters. Finally apply the aluminum foil or polyethylene which has a vapor barrier role.

This type of work will be useful later if we want to set up an attic. In this case, we will have a good protection from condensation in the roof. When we perform a general repair of the roof, it is recommended to apply another layer of waterproofing from the outside. It protects the attic, if this is uninhabited, from dust, wind, snow or rainfall.

Impermeable films have a disadvantage, they do not allow vapor diffusion, which can lead to mold. It is therefore recommended to use a permeable membrane, which facilitates the spread of steam, but does not allow the water in the attic. That is why it is better to ask the advice of the experts, which, depending on the type of roof, they can recommend the best solution. Note that there are special insulating foils that can support a column of water of over a meter, just that every day they allow the infiltration of about 1, 4 kg of water vapor.

Video Insulate A Metal Roof