Expert: Dan Griffin - 6/14/2011

Question
Hello Dan, I am adding a room to a garage and pouring a slab with a footer and stem wall..How do I screed up against the existing wall(concrete stem) and is the expansion joint the only way as it will be highly visible and want to keep it clean?! could I tack something above and screed by pushing up instead of down across the concrete?
Rich

Answer
Rich, you can pour against the stem, but I would prefer using expansion to give the slab a bit of forgiveness.  If looks is the big deal there are plastic caps made for the expansion joint that would be available at any commercial supply house similar to this:
http://www.sandellmfg.com/index.php?page=shop.product_details&flypage=flypage.tp...
These are normally pulled to provide an easy way to install joint sealant, but you could leave the white plastic.

I don't understand the issue about grading concrete up as opposed to down.  If you are talking about a grade line to pour to, you can work to a chalk line or you can attach a board above the concrete and use an ear on the end of the rod.  The big issue is splashing/spalttering concrete against the existing stem when you pour.  Hang visqeen, stand up scrap paneling or similar.  The splatter is VERY difficult to remove and you have plenty of other stuff to worry about during the pour.

If I didn't answer your question, let me know and I will try again.