Roof Insulation

Roof Insulation – The Key to Energy Efficiency!

Insulation is a key part of any flat roof system. There are two main options available. On a “cold roof”, insulation is installed between the roof joists. This can be done using rigid or soft insulation depending on the thermal requirements of the client. It is vital that this is installed correctly and the airspace above the insulation is properly vented. This ventilation can be created by cross battening the joists and providing ventilation via the soffit boards, fascia boards or alternatively through roof breather vents. If this airspace is not correctly managed, condensation can occur on the underside of the roof decking. This moisture can rot the roof from the underside even if the roof is not leaking.

DKeddy Roofing has the knowledge and the skills to install a “cold roof” correctly. We can work with the client or builder and advise on the best solution for your roofing needs.


The second option for insulating your flat roof is to install a “warm roof”. A warm roof eliminates all venting requirements and provides better all round thermal insulation. After the vapour control layer has been fully bonded to the roof, insulation boards are fixed to the roof deck using mechanical fixings. While adhesives can be used to fix the boards to the roof deck, we would normally advise using mechanical fixings if possible. The insulation can come in a range of thicknesses from, 50mm to 120mm, greater thicknesses can be achieved by double boarding if necessary. The insulation we use is called Paratorch insulation, it is produced by Kingspan and is specifically designed to work with bituminous roof systems, Normally we would suggest the 120mm board on domestic roofs as this would give complete roof insulation with no further insulation necessary. Tapered insulation is also available to increase the pitch of a roof. These are insulation boards with a fall of 1:60 built in. These are very useful on roofs that need better roof drainage however they are more expensive.


Roof Insulation boards showing different thicknesses.