How To Seal A Sizable Opening In An External Wall?

This video demonstrates the process of filling or caulking larger gaps or cracks, focusing on the use of polyurethane sealant. The technique involves using a backer rod, bond breaker, and properly applied sealant to handle joints between dissimilar materials with different coefficients of expansion. For large exterior gaps in concrete and other masonry, Loctite PL Concrete Non-Sag Polyurethane Sealant is recommended.

To fill a large gap, work in single, well-done layers one at a time, starting with one excellent line of caulk and then another above it until the gap is one layer shallower. For large gaps in wood, use wood filler or caulk, which is typically a mixture of sawdust and binder. Polyurethane caulking is recommended, starting with a layer, letting it dry, and keeping layering it. Brush it in with an acid/flux brush, and if the gap is deep, fill it with packing sand or similar, then finish with a color matching (steps) flexible mortar mix.

For large gaps in wood, use wood filler or caulk, which is typically a mixture of sawdust and a binder. Polyurethane caulking can be used, starting with a layer, letting it dry, and brushing it in with an acid/flux brush. If the gap is deep, fill it with packing sand or similar, and finish with a color matching (steps) flexible mortar mix.

Inserting a backer rod into the gap and compressing it into the joint until it’s the same level as the surface is also recommended. Apply a layer of sealant bead over the joint. To close a large gap, work in single, well-executed layers one after the other. Two popular sealants for this kind of project are caulk and expanding spray foam, both of which can help close the gap between your roof and wall.