Technical Guidance on Pitched Roof Insulation

Regulation, Ventilation and Insulation of Pitched Roofs

With summer approaching and temperatures rising, now would be the perfect time to consider adding some insulation to your roof which is a part of the construction under the direct influence of the weather conditions, read steaming sun rays that can be ruthless when the summer season is at its peak. Namely, if your roof is not properly insulated, you are risking not only heat loss but also heat gain within your home or your loft space, if there is one. If there is no loft separating your home interior from the roof, then the cold/hot air will flow directly into your home and affect the inner temperature, while if there is a loft space separating the roof from the interior, your loft space may become unusable due to high temperatures where common ventilation will not solve the problem. The insulation will depend on the type of your roof but what we will discuss here is technical guidance on pitched roof insulation.

Know Your Roof

The first thing you need to do prior to adding insulation to your pitched roof is determining the type of roof covering your home since this will determine the type and method of insulation. You don’t need a professional to help you do this but just go look at your roof. If you see two pieces that are joined at the top and falling down at a certain angle, you are dealing with a pitched roof. The pitch is actually the angle the two sides of the roof are set at. Thus, the roof can have a steam pitch which is common for colder regions in order of avoiding water accumulating and freezing on top and also creating some additional space under the roof, while shallow ones tend to create small, unusable spaces under the roof which is often avoided by raising the walls.

Some basic technical information about your pitch roof that you should be aware of and could be important for installing insulation include the roof rafter which is actually a support system for the roof covering (which is important for ventilation and position of insulation), battens which support the tiles and slats and a sarking board which separates the rafters from the roof covering.

Once you have determined all the above mentioned, there is another important difference that you will have to make in order of insulating your pitched roof properly. In case you are not having or simply not using the space under the roof, then you should add insulation at the ceiling level and thus create a so called cold roof construction. This means that you will cut off the interior from the roof space which will remain unheated. On the other hand, if you are planning on using your loft space, then you should probably opt for a warm pitched roof construction where the insulation is placed over, under or between the roof rafters.

Know Your Roof Insulation

There are a few things to pay attention to when insulating your pitched roof. Firstly is the choice of insulation material. If making a warm pitched roof construction, you should opt for some type of rigid insulation boards such as Kingspan K7 pitched roof board orCelotex XR4000 PIR insulation boards, which can be installed both between and over the rafters and offers a level of fire resistance, if important and applicable. Please note that these boards require a breather membrane over the insulation if installed over the rafters and a vapour control layer if installed between the rafters.