I have a 2-story home on Long Island, New York, that was constructed on a slab.
While doing some remodeling, I discovered that the slab was poured in sections that were divided by 2X4 studs laying horizontally and directly on top of the soil (on top of a thin flashing barrier). Plate studs were then nailed to these bottom studs and then the walls were constructed on top of these. The house is about 30 years old.
Termites have turned the bottom studs to powder, causing settling. I am particularly concerned about two 6-foot door openings off of the center foyer, that are topped by 2X12 headers.
I have torn out the termite-damaged wood and I am now left with sections of slab divided by 4-inch wide, 4-inch deep troughs that are 8-feet long. I do not want to replace the damaged wood with more doug fir 2X4’s, and I don’t think pressure treated wood is a good idea on the interior of the house.
I would like to fill the trough with cement and place a steel column on either side of each doorway to support the headers. My thinking is to dig down as deep as possible and also sideways under the slabs as far as possible, so as to create mushroom-like pads to support the steel columns.
I have spoken to several carpenters, etc and keep getting different opinions ranging from no digging (“just pour the cement into the trough”) – to chopping up the slabs and digging a 48 inch footing 18 inches around to support each column (I think that is a bit extreme!).
Any wisdom or advice you can offer me would be greatly appreciated!
Thanks,
RICO