Hi NancyT, This stuff goes in better, in my opinion, if the wall is open. By that I mean ONE side being open. They spray the liquid in and it expands but you need something to spray the liquid onto. If you are removing siding, that's perfect. Right after you remove the siding and make sure you have done everything in the wall that you are going to do, like electrical, TV and telephone wiring, plumbing etc., then put the icynene in. I will expand beyond the wall and will need to be trimmed with a long thin saw. I put Tyvek over the foam then put the siding up. The price is considerably higher than the pink stuff....our house (4400 sq. ft.) was 7K just for the exterior walls. I don't think there is any way this stuff will settle, it sticks to everyting. By the way, you'll want to cover anything you don't want to spray. It's messy and ther IS overspray. It pays to cover everything. The guy that put mine in said there is nothing in icynene that any critter would want to eat. It also does a great job of knocking down sound.