"Upgrading flat roofs as a part of an external insulation project - deep retrofit"
Flat roofs are often also upgraded as a part of an external insulation project. In Green Construction there is a very rough rule of thumb: Traditionally for an uninsulated house we would say that 33% of heat loss is via the walls, 33% via the windows and doors and 33% via the roof.
When Attic Insulation and Double glazing spread across the land the proportion of heat loss that occurs through the walls increased. If a house has current Part L insulation in the attic and windows then 66% of heat loss will be via the walls. Hence our focus on external wall insulation – this is how we get the greatest bang for our buck.
While insulating the attic under a pitched roof is fairly straightforward insulating flat roofs presents a different set of challenges. Many flat roofs in Ireland are uninsulated timber constructions. The upper surface tends to be sealed with felt and tends to leak. They both leak water inwards and heat outwards.
For these roofs we offer a fast and effective solution where we insulate above the existing roof with high performance rigid Polyisocyanurate insulation. Above the insulation layer we will apply a waterproof layer, which seals the roof and makes it suitable for occasion access. The physical characteristics if these composite systems are as follows:
| Property | Units |
|---|---|
| Density (Foam Core) | 32 Kg/m3 |
| Compressive Strength | >150 kPa |
| Water Vapour Resistivity | >100 MNs/gm |
Polyisocyanurate (PIR) based insulation boards are certified for use as in certain External Wall Insulation systems and have been extensively tested for the performance over time. Unlike other rigid insulation systems PIR boards maintain their integrity even after contact with water.
Normally we insulate flat roofs as a part of an external insulation project. So we will be insulating the external walls of the house at the same time. There are normally two scenarios. The flat roof will meet a wall, which overlooks the roof and where the flat roof will be above an insulated wall. In either case we need to carefully fit the insulation layer together to avoid thermal bridging.
Plus you can qualify for a 4000 euro Irish Government grant since we are SEAI approved (Contractor number 11976)
Contact us now to learn how your home can benefit from External Wall Insulation.