Rough Foundation Cost?

[Piper2022]

About to embark on a solid kitchen renovation of my own home. This section of our 1890’s house has a questionable foundation. Before I spend a good amount of time restoring the old fieldstone foundation we have talked about rebuilding this 14×28’ space from the ground up. With this space gone, what would the average foundation cost be for a 14×28 foundation? Would only need to be 3 sided as it’s an addition. 8ft walls, slab floor. Project is in New Hampshire so typical foundation specs for a project with good soils.

I called 4 local contractors about budget pricing and didn’t hear back from any. Everyone if too dam busy! Lol

Any input would be great.

Thanks—Stephan

 

[MossRoad]

Last year I did a 24x24 slab. I made it 12" thick all the way around the first 12" in, and 5.5" thick in the center. It was placed on 16 - 12" X 48" footing tubes. Rebar in everything and pinned to the existing slab it butted up against. I added 1 row of block all the way around 3 sides, so 72' of block. Did it all myself. It was about $3500 in materials.

To figure yours, I would find my frost depth and figure out how deep I have to go.

If I figure, say, 48" down, I'd have to put in:

A 12" wide by 6" deep footing.
A 6" wide by 42" foundation wall.

If I assume you need 14' x 28' x 14' of wall, that's 56' of footing and 56' of wall.

1 x .5 x 56 = 28 cubic feet of footing.

.5 x 3.5 x 56 = 98 cubic feet of foundation wall.

28 + 98 = 126 cubic feet of cement.

126 / 27 = 4.66666 cubic yards of cement.

Then you need to figure rebar, chairs, rebar ties, forms, form ties, release agent, etc. I have no formula for that.

Add up all the prices of those materials, then double the cost for labor and you have your price of what a contractor might charge you to do the job.

 

[Hay Dude]

About to embark on a solid kitchen renovation of my own home. This section of our 1890’s house has a questionable foundation. Before I spend a good amount of time restoring the old fieldstone foundation we have talked about rebuilding this 14×28’ space from the ground up. With this space gone, what would the average foundation cost be for a 14×28 foundation? Would only need to be 3 sided as it’s an addition. 8ft walls, slab floor. Project is in New Hampshire so typical foundation specs for a project with good soils.

I called 4 local contractors about budget pricing and didn’t hear back from any. Everyone if too dam busy! Lol

Any input would be great.

Thanks—Stephan

What are the job site conditions? It it easily accessible? Or will the concrete have to be pumped?
When you say 3 sided, will the additions floor joists be 14’ long from the existing foundation to the front edge of the addition?
If yes, Are you certain the existing foundation meets requirements to support the floor joists?

 

[Snobdds]

15.5k

 

[bigtiller]

After figuring the cost and adding for labor, double that number if you want it done this year.
Everyone is busy and everyone would like to have more workers.

Now is a good time to get on a contractors list for next year.

 

[Piper2022]

Thanks for the replies so far. The foundation is 14’W x 28’L. The total wall height only needs to be roughly 8’ above slab so that limits my concrete volume numbers. The foundation is buried at least 4’ on all sides so we don’t have to go any deeper for frost.

floor joists will run the 14’ width wise so the existing foundation won’t have to pick up that load. So I will need (2) 28’ walls and a 14’ wall at the far end.

forgot to add some: no pumping required, truck can park 4-8 feet from the nearest wall.

 

[Piper2022]

15.5k

Thanks! I was thinking it could be in that range!

 

[jjeff]

Built a 24x30 slab on grade cabin into a hillside had one 30' frostwall 54" deep connected to one 24' frostwall 54" deep the other two footers in the hill were tied into the the tops of the frostwall I then poured a 24' and 30' x 4' tall stem wall on top of the 2 footers on the high sides. Framed on top of the stem wall building a 4' high wall using 2x8s, lumber was cheaper 7 years ago. Cost of footers and frostwall was $5500 with concrete, rerod, and a conveyor truck (a lot cheaper than a pumptruck) The slab I poured myself with friends, was around 1500 with high density foam underneath, wire mesh, and I used fiber reinforced concrete (it was only 5 bucks more a yard) 4" thick, rented a power screed. I helped the contractor a lot doing the setting of forms, excavating, and pouring the footers/ stem wall. I drew my own plans that we're approved by the township, don't know how handy you are but a contractor may work with you and give you a nice discount if your capable of helping not hindering them. Good luck.

 

[Jchonline]

About to embark on a solid kitchen renovation of my own home. This section of our 1890’s house has a questionable foundation. Before I spend a good amount of time restoring the old fieldstone foundation we have talked about rebuilding this 14×28’ space from the ground up. With this space gone, what would the average foundation cost be for a 14×28 foundation? Would only need to be 3 sided as it’s an addition. 8ft walls, slab floor. Project is in New Hampshire so typical foundation specs for a project with good soils.

I called 4 local contractors about budget pricing and didn’t hear back from any. Everyone if too dam busy! Lol

Any input would be great.

Thanks—Stephan

None of our comments matter. You need a quote from a licensed contractor unless you are doing it yourself. All that matters is what someone in your area will do it for. For example, the cost for me to get the same foundation as someone 45 minutes away is double. Why? I am in the mountains and concrete can only be brought up in 1/2 load...but they charge for a full load.

If you haven't gotten call backs from 4, try and expand out to 10 or so....get some quotes.

 

[jjeff]

None of our comments matter. You need a quote from a licensed contractor unless you are doing it yourself. All that matters is what someone in your area will do it for. For example, the cost for me to get the same foundation as someone 45 minutes away is double. Why? I am in the mountains and concrete can only be brought up in 1/2 load...but they charge for a full load.

If you haven't gotten call backs from 4, try and expand out to 10 or so....get some quotes.

True there are lots of factors, I think he was looking for a rough estimate, I disagree comments don't matter how many folks on here have heard of or used a conveyer truck? Contractors can upcharge everything including concrete. it might cost a homeowner 135 a yard for a 3 bag, one contractor gets it for 100 another charges 200 a yard not including the labor to pour it.. the point I was trying to make there are ways to work around logistical challenges, and higher prices as long as your somewhat knowledgeable, semi skilled and the contractor wants to work with you especially in these times when they are back logged, understaffed and overworked . In my area 7 yrs ago a pump truck would have cost me an extra 2k because of travel and availability a conveyor truck located in the area that carried 7 yards of concrete was that much cheaper (saved me on the cost for another truck traveling over 20 miles also) and it could still place the concrete where I needed it.