How to Seal Large Gaps & Fix Door Frames | Sika Boom® Expanding PU Foam Guide

Learn how to use Sika Boom expanding PU foam to permanently seal gaps around windows, fix door frames, and block pests. Watch our step-by-step guide for a perfect, professional finish every time! Welcome to the official Sika India masterclass on using Sika Boom®, our premium expanding polyurethane (PU) foam. Whether you are a professional contractor fixing door and window frames without nails, or a DIY homeowner looking for a reliable gap filler to seal plumbing pipes and AC ducts against pests and monsoon moisture, Sika Boom is your ultimate solution. In this comprehensive video, we walk you through the correct application process to ensure maximum yield, excellent thermal insulation, and a durable, permanent seal. Step 1: Surface Preparation - The secret to perfect adhesion with any PU foam is moisture. We show you exactly how to clean the substrate and properly mist the cavity with water. This critical step accelerates the curing process and ensures the expanding foam bonds flawlessly to brick, concrete, wood, or metal. Step 2: Shake and Apply - Watch the correct technique for vigorously shaking the canister to activate the polyurethane formulation. We demonstrate the essential "upside-down" application method, showing you how to fill deep cavities from bottom to top. Because Sika Boom expands up to 50 times its original volume, we highlight why you only need to fill the gap halfway, preventing messy overflows and costly material wastage. Step 3: Curing and Trimming - After application, we cover the expected tack-free and cutting time. Once the foam is fully expanded and hardened, we demonstrate how easily the excess can be cut away with a standard utility knife. This leaves a neat, flush surface that is immediately ready for sanding, plastering, or painting. Sika Boom doesn't just act as a simple gap filler; it provides outstanding acoustic dampening and thermal insulation for Indian homes. Master this technique today to eliminate rework and deliver professional-grade results on your next project.