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January 9, 2009
Estimates for Cellar Renovations
I have an unfinished cellar in Park Slope and am ready to start looking soon for architects/contractors. Before I do this, I would really like to have some idea of what I am talking about vis-a-vis what I want to do, and this will depend on cost (I have a feeling some of my ideas will cost more than I am prepared to spend).
So here are my questions: Does anyone have a ballpark/rule of thumb way to estimate excavation costs (e.g. $ per cubic foot?), as well as the cost of underpinning party walls ($ per vertical and/or horizontal foot?) as well as for pouring new concrete slab?
The house is brick all around, 35 ft long by 19.5 wide.
Much obliged, Brownstoner people!!
Comments
Use the following unit rates (based on using licensed, insured contractors, not day laborers picked up off the street):
Excavation by hand & load into dumsters: $90/CY
Transport and dispose of excavated material: $35/CY
6" thick concrete slab on grade with mesh reinforcement and granular base: $12/SF
Concrete underpinning including reinforcement and formwork: $2,000/CY.
Applying these numbers to your particular basement size, here are your specific calcs based on an assumed 2' 0" excavation depth and 1' 0" party wall width:
Excavation & disposal: 35*19.5*2/27*($90+$35)=$6,319.
Slab on grade: 35*19.5*12=$8,190
Underpinning:(35*2+19*2)*(1*2)/27*$2000=$16,148
Total: $30,657
The above does not include any additional work that may be necessary such as setting existing doors to a lower elevation, relocating steam heating return pipes that may currently sit on the ground adjacent to the party wall, refinishing existing walls, new ceiling, any temporary overhead pipe relocation to accomplish ceiling work, etc. etc.
I currently have the same deal as I guess you do, unfinished space with dirt/boulder floor. Since I use it basically as storage/worshop space, I've never had an overwhelming desire to do anything to it, but, if I did I think I would sacrifice some floor space by keeping the excavation the same distance away from the perimeter walls as the excavation depth and creating a concrete "step" around the edges, thus obviating the need for the underpinning. It's all to do with not encroaching on the "line of influence" of the load transfer from the walls to the ground.
Posted by: johnife at January 8, 2009 3:12 PM
whats the multiplier for poor access?
Posted by: jp2 at January 8, 2009 3:18 PM
We did this in early 2007 and have a completely finished cellar with 8' ceiling height. It is now totally habitable space (without of course being deemed such by the DoB). We put in a 1/2 bath, huge laundry, reduced the size of the mechanical room, moved electric meters, built internal walls as well as had a matching (to the rest of the house) wooden staircase made with Mahogany railings, tiled the entire floor and put in radiant heat under the tiles. We also put in an I-beam to support main dividing wall running the full length of the house.
As this was the house's foundation we were dealing with we ended up not going with the cheapest contractor but probably the one who was most expensive but I wasn't prepared to take any risks and has watched this contractor build a house from scratch and knew I as getting top quality work.
The total we spent included architect and expediter fees (the DOB is a real pain and we had three goes at getting approval including eventually getting post amendment changes approved to what we'd originally applied for.) we also moved a ton of gas and waste pipes around the ceiling and while this was well worth it for to lean up the ceiling it added a lot to the cost. We own a three family and so had more pipes than most town houses and none of the 4 full and 2 1/2 bathrooms in the house share any plumbing. we also installed a sump pump for the cellar plumbing waste.
We have 5 rooms down there; 1) media room/Kids playroom, 2) Mechanical Room, 3) laundry, 4) 1/2 bath as well as 5) an office/gym.
Finished internal space is 20 x 38 although the foundation is 22 x 40 ( we didn't excavate the mechanical room which is approx 6 x 8)
Total cost $200,000
Posted by: 99luftballons at January 8, 2009 4:12 PM
Hi
If you are interested, we can come out to give you a free estimate on what it would cost for labor only (this way you can save more and would be able to be within your budget). Myself or my partner can be reached at the number below. Please check out our website if you need to see pics of our work (site is still under renovation because we are new). I have been in the business for 6 years now and currently started my own home based business.
www.newarrowconstructionllc.weebly.com
Thanks
Sooknarine Sookhai (aka. Dinesh)
Christine Stephen (partner)
New Arrow Construction LLC
(347) 227-5834
Posted by: nightingale at January 8, 2009 5:25 PM
WOW. This is fantastic stuff, people!!! Thank you thank you thank you!!!
Posted by: deetrane at January 8, 2009 5:57 PM
Oh, and 99luftballons - do you mind saying which contractor you used?
Thanks again.
Posted by: deetrane at January 8, 2009 5:58 PM
Wow, thorough overview Johnife. Any recommendations on whom to use for the slab on grade?
The need for underpinnings depends on how far down your current foundation goes on all sides. I did some exploratory digging and found that on one party wall the foundation went down at least 15" below my current cement slab floor, which should let us go from short of 7' to about 8' net when we do this.
Since this is such a large part of the budget, Deetrane, you may want to do the same.
If even you do not plan to do this to code (i.e. using bedrooms and full bath in a "cellar"), I would plan to insulate the mechanical room with fire-proof materials and door(sorry for the imprecise description) and provide a make-up air, typically a 4" metallic duct to the outside. You likely do not have this today.
If you have brick columns under a support beam that runs from the front of the house to the rear of the house as we do, you will want/need to replace them with more compact metal lally columns to the new floor. However, you will need footings at these points in the floor as the standard floor will not suffice. I suspect it would be difficult to replace a current beam or set a new metal beam and it may not be necessary.
We plan to put in radiant heating as a 4th zone to our current Burnham, just like Nena. Our house is 17.5 x 35 and I plan to do the excavating and slab work for 20K. Call me crazy, but we will do a lot of this ourselves.
While we have filed permits for other work, I currently don't plan to file for this work as I am not changing egress, plumbing, or the use of the space. Anybody know if a simple drop of the floor requires a permit?
Posted by: renomandru at January 8, 2009 6:18 PM
You're a madman. But it would be great if you did a B'stoner reno-blog on it.
Posted by: deetrane at January 8, 2009 6:32 PM
We did this about 8 years ago and I have two questions for you before you begin: (1) have you ever had any water in the basement, and (2) is there any asbestos?
One thing we did that you should consider is replacing the old cold water feed and steam heat return before they are buried in any new walls. You don't want them failing after the job is finished.
Posted by: marty362 at January 8, 2009 6:47 PM
renomandru...all you need is one neighbor to get pissed at you and call 311 and you will nailed and issued a stop work order with the 5000 fine and attendant headaches...do not cheap out and try to game the system...the dob has been converted into a fee generator under bloomberg, more about generating violations than insuring safety...sorry to be a downer, but hire an architect that you trust to file
Posted by: eman1234 at January 8, 2009 9:17 PM
Renomandru,
Its a really bad idea to not file a job that involves your (probably shared) foundation. Its almost impossible to know what you are going to find when you start digging.
The main issues:
1. You should have the right insurance for something this risky. If you don't file and tell the insurance company ahead of time, you probably won't be covered if you damage your neighbor's homes.
2. The kinds of damage that can happen cannot be repaired easily and might not be repairable at all.
3. What eman1234 said.
Posted by: thecomputerguy at January 9, 2009 12:03 AM
deetrane
We used http://www.scordio.com/index.htm
Like others have said this is NOT something you can do with out using properly licensed,insured and experienced contractors and you must have all the requisite DOB permits.
Over the years old row houses settle/move and often all lean slightly on each other. The top of our house is approximately two inches inside our lot line and the integrity of the foundation is paramount. Both side walls are party walls with your neighbors (ours was brick but their side wall was timber) and underpinning needs to be done slowly, properly and carefully.
If this is done poorly the catastrophe that could occur is mind boggling and would open up an endless round of litigation.
Posted by: 99luftballons at January 9, 2009 12:01 PM
I appreciate all of the well-meaning and well-informed cautionary tales.
I agree that messing with foundations on townhouses in NYC is a business for licensed pro's armed with a permit.
If you are not impacting the foundation, and don't need underpinnings, however, the risks of lowering the basement floor are significantly less.
I currently have 3 permits plastered to my front door but during the past 7 months I have seen absolutely no other permits in my immediate neighborhood with plenty of substantial work going on.
In the tonier parts of Brooklyn, it seems one does nothing without an architect, licensed contractors, permits, structural engineer, interior designer, lawyer, dog walker, etc.
In poorer areas, much renovation work will not follow protocol because it would simply not be affordable or justifiable. One takes risks but they are calculated risks.
In old school Brooklyn (and other boroughs), you build relationship with your neighbors, share tools, know-how, and contractors, and look the other way when necessary. When I tell my neighbors I actually hired an architect for the minimal work I am doing, they react with amusement or surprise. I feel like I have to justify it.
And now that the money is tight, I have to justify it to myself. Let those fingers wag.
Posted by: renomandru at January 9, 2009 3:05 PM
99luftballoons-can you post pics of the project?
Posted by: housebywe at January 11, 2009 10:28 AM
I did this as part of my renovation 2 years ago. Basically I had the dirt dug out to the
bottom of the footing, netting me 8" of additional ht, leaving me with a 7'2" ceiling ht.
In the major reno I made sure that all pipes and ducts were located along the bearing
beam or at the far side wall. Also once the floor was poured I had the brick walls
powerwashed to get rid of paint and exposing original brick -- including all the brick piers.
Only this year did I finish the space. I installed brazilean walnut floating floor, 8" base
along the brick (to cover the ugly brick that was below grade), and a few sections
of baseboard electric heat. The reason I went electric is that the space is not used
alot --- I currently call it the NFL lounge --- and my preferred heat -- radiant --
would not be cost effective given the time it would take to bring the floor up to temp.
That being said, I wish I had gone radiant as the floor does feel cold if you spend
much time there.
One other thing I did was install a skylight as the access door in the coal chute area
the opens to the front stoop area --- so I actually get some natural light down there.
My best guestimate of the cost to date is $30K. Given that I got 700sqft of living space
it works out to $43/sq ft --- a worthwhile investment in my mind.
Next project is a small 6'x6' corner bar.
Posted by: daroogle at January 11, 2009 11:04 AM
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