A flat roof is an attractive architectural feature that not only makes your home look more modern but it also offers extra square footage for you to use. Therefore, if you have a flat roof you can choose to turn it into a terrace or just leave it as it is.
Either way, you need to insulate it properly so that the rooms below are not suffering from thermal bridges, leaks, or other temperature fluctuations.
The best way to insulate a flat roof depends on a few factors including the arrangement of the layers of the roof, the usage of the slope, the type of roof, and whether it is ventilated or not ventilated.
A non-ventilated flat roof is a structure where the ceiling is also the roof. Screed is used on top to arrange the slope.
The way to insulate this type of roof is to lay a vapor barrier film on the structure of the ceiling and add thermal insulation and waterproofing on top.
Some roofs will consist of a bitumen membrane and have welded bitumen membrane of two layers.
Styrofoam board is one of the most common insulation materials. This is a cheap and lightweight solution.
More reliable materials include rigid mineral wool boards. These boards are fire resistant, however their efficiency reduces when used in damp environments.
PIR and PUR foam boards are also common solutions for flat roofs that do not have a lot of thickness.
In addition, spray polyurethane foam is an alternative to boards. This spray system allows you to eliminate gaps between the boards and ensure a light but thick insulation material.
Another option similar to PIR and PUR boards is polyurethane foam. This foam is more flexible and easier to apply on the roof. It eliminates the necessity to cut boards and it seals all gaps from the outside, also protecting against water and UV radiation.
A ventilated roof on the other hand has an air gap between the ceiling and the roof. Thermal insulation is placed on the structure of the ceiling.
The best type of insulation for ventilated roofs is styrofoam boards as well as wool boards. If you want to use something else rather than boards, spray foam is a great alternative.
For more information on how to insulate a flat roof, contact us at RH Renovation NYC. Whether it is a repair or replacement of a flat roof you need, we got you covered. We can also help inspect or maintain your current flat roof structure. Get in touch today!