I have 12' of termite damaged (6"x6") sill that sits on top of the cinder block foundation of the front dirt filled porch. The rim joist has some minor damage, too. The floor joists are good. This is an 18 year old 2 story house that sits on a crawl space. I can only work from the inside unless I break up the porch which I do not wish to do. I need to replace 6-12' of the damaged sill and because I cannot gain access from the outside, I will use pt blocks to cover and add support to the rim joist. I will replace the sill in sections because I don't want to yank out a 12' piece all by itself. Questions? 1.) What is the smallest piece of sill that I can remove at one time and keep the job looking professional? 3 feet? 4 feet? 6 feet? 2.) How many steel floor jacks will I need to use per section and what strength should they be? 3.) How far from the sill do the jacks need to be placed? (I won't be able to provide any jacking or support from the outside, inside only.) Right now there's no sagging but the repairs need to be done now or eventually before the house is ever sold.