[slowjo]

Hey guys,
So I dont know if any of you remember but we had some idiots pour a footing ontop of our field stone foundation so we could rebuild the last sections of the foundation wall that was falling in along with the joist ends and whatnot.

Welp we knocked out pad the guys had poured. It tiook me 30 minutes with an 8lb hammer to knock out the whole footing. They had just filled it with bricks, rotted wood and a can.

 

[slowjo]

So We have made new forms and are gogin to pour our own footing. A few questions.

1)
We have regular steel rebar. Should this be alright, or should we have gotten the anti-corroding sort? You nkow the green stuff.



We were planning on pouring a 16" wide footing about 23 ft long. The depth will vary from 7" - 3" because the field stone is pretty un-level due to the large stones they used.

Our plan is to use 3 pieces of 1/2 rebar spaced about 4 inches the length of the form.

2) Should 1/2 be appropriate? Or is that a bit big and 3/8's is better?

3) How often should a cross piece be placed?

4) We plan to use the yellow bagged quikrete. Any reason why I should not use this in this application and instead mix my own portland/sand?

 

[slowjo]

As you can see we have been sistering the joists as well. The original joist ends have rotted out completely. We notched the new 2x8's so there is 4 inches left ontop like the original.

Does anyone see a problem with this?

I guess I fear the wood will want to split. Do they make any sort of those metal plates like you would use to construct trusses for the joist end peice to ensure they all stay together?

 

[JohnCarpenter]

How much weight will the footer be supporting?
What are the soil mechanics involved?

I would not have cut the joist like that, they are weakened now. The weight can split them right down the middle like splitting firewood.

This footer supports the whole house. If it is not properly done, you can be looking at massive damage to the rest of the house.

You need a professional contractor to come out and look at it.

_________________________
Johnny Jackson
http://www.jljacksonremodeling.com

 

[slowjo]

This is an 1880's balloon frame colonial.

There are no real soil mechanics involved with this 'footer'. This footer is sitting on top of the original field stone foundation. Not soil. Its stated purpose to make a level area for the blocks that will meet the sill plate to lay on.

The contractors that looked at it had all suggested cutting the joists like this. The old joists were cut exactly like this. The very ends rotted due to a water issue. These joists are nailed to the old joists and extend the entire way across the basement where they are notched in a similar fashion on top of the center support beam.

I was initially concerned about cutting them like this, and had thought like what you had said. But I was told it would be a non issue by 3 different contractors. The joists are 2x8 and the have 3 1/4 notched out on the ends.

If anyone knows a good structural engineer in the Ma area please feel free to msg me.

 

[jaros bros.]

Yeah, that's a major mistake on the joists unless the heel is going to sit on something or you use joist hangers. Big mistake if not dealt with.
I also second the previous post to get an engineer or professional that can help out. There's no reason to take unnecessary risk.

 

[Aggie67]

Yeah, that's a major mistake on the joists unless the heel is going to sit on something or you use joist hangers. Big mistake if not dealt with.
I also second the previous post to get an engineer or professional that can help out. There's no reason to take unnecessary risk.

I agree.

I wouldn't have notched the joists like that, either. And you should at least have an engineer bless it and put a stamp to it (ie, design liability covered). That's a big repair you're doing.

Also, a 3 inch deep poured concrete "footer" is going to be meaningless on top these field stones, rebar or not. A lot of thoughts are flying through my head. A local licensed engineer will probably be thinking the same thing I am. You need to call one.

 

[slowjo]

I agree.

I wouldn't have notched the joists like that, either. And you should at least have an engineer bless it and put a stamp to it (ie, design liability covered). That's a big repair you're doing.

Also, a 3 inch deep poured concrete "footer" is going to be meaningless on top these field stones, rebar or not. A lot of thoughts are flying through my head. A local licensed engineer will probably be thinking the same thing I am. You need to call one.

Thats kind of vague about your thoughts on the footing. Could you be a bit more specific. Let me explain what I mean. In most spots it will be 7 inches. In a few spots (probably 1 ft total area) where the stone has a 'hump' in it. It will be probably 3-4 inches in depth.

Originally it was brick laid directly on the field stone. It was there for 130 years, held the house up even though I could pull all the bricks out freely. Maybe I should lay solid block directly on the fieldstone then? It seems to me a course of concrete to level the house will do just fine. We are having a mason come today to look at doing it.

Also there is a PT 4x6 going ontop of the foundation for a sill plate. Thats why the boards were notched like that. Do they make joist hangers for 2x8 that can nail onto a PT 4x6? I would probably need double joist hangers because the thickness is more like 3.5 inches total between the two joists. Some joists are doubled up bringinging the thickness to 7 inches wide.

 

[pls8xx]

From the photos, it looks like you have about 10 to 14 inches from top of existing footing to bottom of joist. I think I would look at something as in the drawing bellow ...

 

[Daniel Holzman]

The rebar will accomplish essentially nothing in the application you present. You need a minimum of 2 1/2 inches clear between the edge of the concrete and the edge of the steel to minimize problems with water damage. This means that in a 7 inch thich slab (the maximum in your case), your rebar will be sitting almost directly on the neutral axis of the beam, where it performs ZERO work. Where the slab is thinner, you may not even get the minimum clearance.

The only thing the rebar will provide is minimal crack control, no structural benefit. By the way, this topic has been covered extensively in this forum, look through old threads. Not to be rude, but it seems to me that you have limited structural knowledge, and this is a fairly extensive project, you really ought to consult with a structural engineer or at least an architect or a knowledgeable contractor. I am surprised you could pull a permit for such extensive work without an engineering consult, but regardless if you need a permit, you really need to get some design work on the project by someone who understands structural engineering. Getting free advice from a DIY forum from people who have never seen your site is a good way to understand the issues, but is no substitute for professional consulting.

 

[Aggie67]

Thats kind of vague about your thoughts on the footing. Could you be a bit more specific. Let me explain what I mean. In most spots it will be 7 inches. In a few spots (probably 1 ft total area) where the stone has a 'hump' in it. It will be probably 3-4 inches in depth.

Originally it was brick laid directly on the field stone. It was there for 130 years, held the house up even though I could pull all the bricks out freely. Maybe I should lay solid block directly on the fieldstone then? It seems to me a course of concrete to level the house will do just fine. We are having a mason come today to look at doing it.

Also there is a PT 4x6 going ontop of the foundation for a sill plate. Thats why the boards were notched like that. Do they make joist hangers for 2x8 that can nail onto a PT 4x6? I would probably need double joist hangers because the thickness is more like 3.5 inches total between the two joists. Some joists are doubled up bringinging the thickness to 7 inches wide.

You'd be better served by doing a masonry wall than concrete. Pouring 3 inches of concrete with rebar over a fieldstone foundation is the last thing I would do. Especially if the thickness of the concrete varies up to 7 inches. And even more so if there is movement in the fieldstone. I can't give you the advice because I'm a NJ PE (not MA) and the liability is crazy, even though I'd know what to do, and it wouldn't be poured concrete. That stinks to read "I can't give you the advice" coming straight from a licensed structural engineer, I know, but it's reality: I'm in NJ, you're MA, and both the law and my liability insurance carrier says I can't.

I have to ask, what is so hard about calling in someone to properly engineer and design a solution? If you called me, and I was a MA PE, you'd have a set of drawings to go by, with manufacturer's part numbers and material specs so you could DIY this.

For the hangers, go to a manufacturer's web site, like Simpson's or USP, and download a catalog. Everything you'd want to know is in there.

 

[Aggie67]

From the photos, it looks like you have about 10 to 14 inches from top of existing footing to bottom of joist. I think I would look at something as in the drawing bellow ...

 

[slowjo]

Thanks Aggie, and Deniel I do appreciate the insight. Really.

After having a few concrete companies look at it, the suggested route was to use hollow block filled with mortar and use mortar directly on the fieldstone to bring it to level. I have been trying to contact several engineers but have had next to no calls returned, the one that did cant come out until June, and we need the house buttoned up in less than a week. :thumbup: