[harpua728]

There's a decent sized gap (about 1/32") between the top header trim around my front door and the wall. When I put my hand up there I can feel cold air coming into the house.

The only caulk I have on hand at the moment is a DAP Alex Flex moulding/trim sealant (http://www.dap.com/dap-products-ph/alex-flex-premium-molding-trim-sealant/).

Is this good enough to use to seal this gap around the trim and stop the cold air form coming in or should I use something else?

Thanks

 

[Windows on Wash]

Cold air is from the outside wall. While sealing the gaps on the interior will help, the larger issue is the exterior sheathing, top plates, and other breaches in the envelope.