Concrete Slab / Expansion?

[DD716TED]

I want to pour a concrete slab that on two sides will butt up against an exisitng concrete slab / house concrete block skirting. Is expansion material installed on these edges before pouring the concrete or should I just frame the entire slab, pour concrete, remove frame and then fill gap with something?

[HayZee518]

put in a composition expansion strip and do your pour

[pushkins]

Like Hayzee says, you need to add your expansion material BEFORE the pour, that way the concrete will push up against the expansion material (felt or foam) and make a nice clean finished edge. To try to add it later will lead to all sorts of problems.