I`m adding an addition to my house,the addition will have a full basement under it.The house has a block wall foundation, the addition will have a solid poured(insulated forms)concrete walls. What is the best way to tie into the block wall with the solid wall? One way I was told,is to break holes in the block and when the new walls are poured the concrete will flow into the block. Is this the right way? Or is there a better way?

sp,

yikes! bust through block? Not me.

but if thats what you/they are going to do, better waterproof the crap around there! Should waterproof along the entire block wall and around addition and, backfill w/gravel-peastone,have seen people builde addition and NOT waterproof the existing back-whatever wall and...leak.

They may NOT have a problem, a leak, any cracks BEFORE building addition BUT its quite possible that when excavating and using heavy equipment near existing foundation wall could CAUSE-Cracks, then leak.Yep, using heavy equipment near existing wall(s) COULD cause damage to existing wall, the weight of equipment alone causes an Undergroung-Lateral-surcharge pressure that is transmitted to existing wall.... my 2 cents.

read last para -Careful on the Construction Site http://www.bobvila.com/HowTo_Library/Why_Foundations_Fa...oundation-A2095.html

I'd be thinking in terms of something like a 2" x 2" steel angle anchored the full length of the block wall, so that the outstanding leg is at the center of the new concrete wall. Or possibly steel dowels drilled into the block, maybe every second block, extending out into the center of the concrete wall.