I am remodeling a kitchen and the architect has suggested I remove a short load bearing wall. The wall is supported in the basement by a steel I-beam that rests on one end on the concrete foundation wall and the other end rests on a steel column. Approx. lenth of I-beam is 10 ft.
In the “new” kitchen, a stove and range hood will sit where the old wall existed, so the architect plans to support the load by using two beams about 18-24″ apart. The beams consist of two laminated 2x10s and are supported on each end by 3 1/2″ square laminated posts. The beams are 18-24″ apart so there is a space to run the vent from the range hood.
In the basement, I need to install two new steel columns, one on either side of the existing steel column. The new columns will be about 12-14″ from the existing column. The building inspector has told me my slab is most likely 4″ thick and I need a footer of 12″ on all sides at least 10″ thick.
Here’s my stupid question! I’ve poured footers for my deck before, so if I rent a saw at Home Depot and cut out the concrete for the new footers, how do you support the new steel columns while the concrete is drying? The old column is beneath the surface of the existing slab. What rebar, if any, should I use to reinforce the footers? Should I use any particular type of concrete? (Home Depot has noncracking or premium plus other grades). THANKS!
Replies
You don't put the new columns in place until the concrete has set.
Which means you either leave the loads bearing where they are now, or if that isn't possible, you install temporary shoring until column installation occurs. Waiting a week after the pour isn't a bad idea.
You can use the high-early concrete if you want, but it isn't necessary. The standard bag mix should be ok. Rebar can be used if desired, the 1/2" bars commonly sold at HD will work.
carpenter in transition
OK, If I understand this correctly you're adding columns in the basement 9" to 12" beside another column to carry the load in the kitchen which is on the floor above the basement.
Why can't you weld a bracket to either side of the basement column or, better still, weld to the steel I beam to carry the load. Seems to me the existing column is OK for carrying the load. You just need an offset around the stove and range hood.
Why can't you weld a bracket to either side of the basement column or, better still, weld to the steel I beam to carry the load. "
Link,
Bolting IMO is better than welding. Properly welded, yes will be stronger, But...rarely happens in the field.
WSJ
I agree. Bolting in the field is better than welding.
"I agree. Bolting in the field is better than welding."
Link,
As an aside, many people don't realize that a very long I-beam can be fabricated out of bolted together C channel, which can save on the transport cost, as well as the cost of a crane to move the monster in place.
WSJ
It's a bit odd to have a steel beam pocketed on one side & sitting on a post on the other....
If you have access to a structural engineer, it may not cost you much money to save a lot of hassle and expense. It seems that cutting the slab to retrofit footers is extreme, unless there is a huge load. Does the inspector suggest the footers because that is actually what the load requires, or is that just in underinformed application of a rule of thumb? I have done a lot of work on the historic building that the local structural engineers have their office in, and they will often help me design solutions for similar situations I have encountered. You may well be able to use 1/2" plate under your new posts to spread the load sufficiently for bearing on the 4" slab.
And here I was gonna suggest he go down two feet. Code round here.
J. D. Reynolds
Home Improvements
You might also try doubling or trippleing up the joist that is under the new post. Since the offset is so small, that might also work. A few dollars for an engineer to do some calculations or come up with other ideas might be worth it. He'll have the advantage of seeing the job.