Where to find small pieces of foam

[RobertInOntario]

Thanks for your feedback, this is very helpful.

So I'm going to visit my local Home Depot and Lowes stores, etc. Yes, there are several construction sites in my neighbourhood. Our neighbourhood used to be made up of postwar bungalows (such as ours) and they're gradually being replaced by monster homes. I have seen insulation foam in the past but it's been rare or I've been in too much of a hurry to stop. I'll try to search more & be more patient!

Cheers, Rob