Building Homes or Extensions/load bearing walls


i want to construct first floor on existing 15 yrs old load bearing structure.but,in order to make the room bigger,i have to rest one 9 inch & one 4 inch wall directly on slab with no wall beneath.first,can i do so with inverted beam over the slab& under the the said walls.what care i should take

Hi v b, I'm not getting what you want to do.  When you say 9" wall do you mean the wall is 9" thick? Or are you moving the wall out 9"? It is possible to transfer the load to a beam as you suggest but each end of the beam will need to have enough supporting capacity to hold half of the total load.  If you are on the edge of the slab and can get under it, it is possible to reinforce the edge of the slab by pouring a new footing underneath.  Or you can cut a strip out of the slab and pour a support footing thick enough to carry the new load.  If you are only going one story high your footing and/or slab may only need to be as little as 8" thick with one #5 rebar in it..this of course depends on the type of construction and the weight of materials involved.  Without more information, I'm afraid I can't give a lot more advice.  Please feel free to write again regarding this or other matters, sincerely Bruce Johnson  

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Bruce E. Johnson


I can answer any construction related question in regards to carpentry, concrete, drywall, masonry, structural elements of any type of building, residential or commercial. Interior or exterior.


Custom Commercial and residential buildings. Churches, theaters, schools and auditoriums. Most recently I am working with the Catholic Church on several design build committees. I have a website related to scheduling and project supervision. Although my expertise is more related to multimillion dollar commercial, educational and theatrical projects my generous credentials in residential and remodelling construction make me a viable source of information regarding all forms of building questions.

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