Expert: Dave Johnson - 1/28/2009

Question
QUESTION: My existing master bedroom addition ( single story in Buffalo NY ) was built on posts and piers, has a two foot crawl space.  I want to put a foundation under it.  what size beam do I need to temporiatly support the room during excavation?  The roof is 24 foot trusses so the supporting distance is approx. 16'.  We intend to block one side at a time.

ANSWER: Hi Joseph,
If the span to be carried is 16', you'll need a steel "I" beam
that is 6" w x 10" h.

Be sure and use one long enough to block well beyond the excavation area.

As a suggestion, you should think about using ICF's for your foundation. They are great to use under an existing bldg.
Go to  www.nudura.com for a detailed look.

Best of luck, and if this isn't clear, mail me again.

Dave

---------- FOLLOW-UP ----------

QUESTION: Thanks, now about the icf's.  the concrete is pumped in so I would have to keep those blocks down some and then frame up to the existing joist system, right?  thanks again. Joe

Answer
Hi Joe,
Yes, you're right, and if your close to the ground you may want to use pressure treated lumber..........

That close to the ground, you could do it without a pump truck (saving 6-8 hundred dollars) just have a piece of plywood for the concrete to land agaist and go a bit slower than normal.

Dave