AIRSTOP FLEX FEE, with its divided backing strip, plasterable fleece and a generous layer of pure acrylic adhesive, makes it the perfect solution for bonding back to semy rough surfaces and well as smooth surfaces of all types. It offers the ability to seal door and window details quickly and easily. Installation is quick and consistent. The fleece like fabric allows the product to be painted or plastered in, ensuring seamless integration of the airtight layers. Its high-grade adhesive layer enables compliance with the higher standards of RAL and ÖNORM B5320 around window details. Use this tape for blockwork, precast, timber, membranes and any clean non, porous surface. Select the widths according to your detail and final makeup. As an example, when finished, the face of all porous blockwork should be sealed. This can be done by using a wider tape or by sand and cement tying into a smaller tape; it depends on your detail; if you have a cavity closer, the tape needs to go from the window frame back over the cavity closer and back on to the blockwork no less than 50mm. When sealing a window, the window must be fitted with all the necessary details correctly. We highly recommend using our ISOWINDOW WZS Soft Cell Foam around all your doors and windows before applying the tape. This foam has been designed primarily for this purpose and offers features other foams can't match. Its ability to expand and contract, allowing vapour to pass through it and its sound performance make it the optimal foam for window installation. If your window supplier has foamed the windows, ensure they are entirely foamed without gaps or daylight before applying tapes. Once the opening has been foamed and trimmed back accordingly, it's time to prepare the head reveal and sills. For blockwork builds or dusty substrates, we recommend cleaning off excess mortar and dust before priming, although our products, like many others, will stick well to all clean and dust-free surfaces. Surfaces must be solid, dry and dust free; also, wipe down the frame with a dry microfiber cloth to remove dust and moisture before applying the product. As a rule, we always recommend priming porous and dusty surfaces to achieve the utmost bond. You can easily prime using our very user-friendly UNI SPRAY or our water-based BUBI LF primer by brush; a little messier and takes longer to dry than the spray primer itself. You will need approximately one can of spray primer per 2 rolls of Isowindow Feba soft. For BUBI LF 1 litre per four x 100mm tape would be required. We strongly recommend our Tape Presser; this is designed to help you apply pressure to the tape, which will benefit your fingers and the bond of the product. Please see our video installing a window tape if you need further advice or information on the application process. You can also contact us; one of our team members will be happy to go over the process in detail.