More Picture Of Insulating An Existing Flat Roof From Inside HD Image Size. While a great option for new flat roofs this material may not be best for existing flat roofs as it works by expanding. Dec 12 2011 Your two best options are spray foam insulation on the underside of the roof sheathing -- an installation which will require the ceiling to be removed at least partially -- or the installation of rigid foam on top of the existing sheathing.
The snugness of the foam itself should be sufficient to hold the strips. We recommend having at least 20 r value worth of material for optimal energy efficiency. This system was often used in the past but is not recommended nowadays.
Dec 12 2011 Your two best options are spray foam insulation on the underside of the roof sheathing -- an installation which will require the ceiling to be removed at least partially -- or the installation of rigid foam on top of the existing sheathing.
For warm flat roofs where insulation is added above the roof joists the first area to check is the condition of the existing waterproofing on the roof. Jun 29 2010 I would say the easiest and most cost effective is quilt insulation between the existing joists Im assuming its at flat roof Tis obviously requires removal of the existing ceiling. Sep 03 2019 We have an extension with a flat felt roof the difference between the extension and other rooms is about 8 deg F. Creating a void between the old ceiling and new is better but ideally you need to eventually consider insulating the top of the concrete roof with solid insulation and a better covering GRP or EPDM.