Author Topic: Interesting Floor Dillemna  (Read 5052 times)

thelamb

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Interesting Floor Dillemna
« on: March 03, 2014, 04:35:06 PM »
When people come over to my "house" for the first time, there's usually some confusion:  Why are there two front doors?  Is this an apartment and who's in the unit next door?  It's that it wasn't always a house but originally more of an early 1900's mixed-use building with retail (bar then corner grocery) on bottom and small-ass apartments on top, hence the two entrances.  At some point (assuming when it became a grocery) a 4" concrete slab was poured over the original oak floors.  At some other point the sheer weight and age led to some sinking.  This was all reinforced but the floors became hella unlevel. 

When I bought it it had been a domicile for about a decade and the concrete flooring was carpeted over with a raised platform over the most un-level area.  I gutted, reconfigured the layout and rebuilt.  Everything turned out great except the floors.  I went through bag after bag of self-leveling stuff before laying a 3/4", click-and-lock, floating bamboo floor, which now drives me up a wall.  They bounce a ton (a year later), scratch easy, always look dirty (cuz they're dark), and are starting to separate in several places.  I think they will significantly impact resell value and just ruin an otherwise good remodel. 

Now, I'm considering my replacement options.  There are two big ones being considered and probably a million I'm not.  Both options involve ripping up the bamboo. 

Big option 1:  somehow cut out all the concrete without affecting the existing walls, counters, built-ins, etc.  Build a new frame on top of the existing hardwood, which I can assume is trash now, but shim and rip where necessary to make perfectly level.  Lay sub floor, then go with a hard wood that is either glued or nailed down.  Concrete would need to exist under the cabinets, island, built-in and a handful of interior walls. 

Negatives:  sheer ton of work, amount of dust that will go everywhere, complexity of cutting or chipping out around existing structures, and the mystery of what's under there.  Positives:  if done right, it would be a truly new floor that should last for decades, it would eliminate my biggest barrier to running new electrical or plumbing lines for a couple future projects I have in mind.   

Big option 2:  skim coat the concrete floor with those new, fancy overlay products.  Positives:  much less work, would eliminate all bouncing and give a nice, strong, industrial look.  Negatives:  probably wouldn't make it truly level.  would be cold on the feet and less appealing to those not into the complete industrial look.  would add yet more weight to the structure. 

I plan to trick some architects into taking a look and giving some advice but I wonder if any DIYers or pros out there want to weigh in.  Oh, and we're talking somewhere between 800 & 900 sq ft. 

Thanks!

PMG

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Re: Interesting Floor Dillemna
« Reply #1 on: March 03, 2014, 04:43:50 PM »
Do you have access to crawls paw or basement under the building?  Do you know what shape the original wood floor and the joists,beams or foundation are in?  I would be suspicious of deterioration there.  Was there cracking in the concrete when you leveled and installed the bamboo? 

I don't consider myself an expert but 7 years in rehab and construction have taught me that it is always worth doing the job right and that usually means going back to the beginning and starting over. 

thelamb

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Re: Interesting Floor Dillemna
« Reply #2 on: March 03, 2014, 04:48:54 PM »
Yeah, full access via basement.  95% of original flooring looks good from underneath.  Some cracking and sinking had occurred but the foundation, joists, etc have been reinforced a ton. 

Jack

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Re: Interesting Floor Dillemna
« Reply #3 on: March 03, 2014, 08:16:33 PM »
Option 3: carefully remove the cabinets and built-ins, jackhammer out the concrete, level the floors by jacking them up from below, install 3/4" nail-down hardwood directly to the old wooden floor, reinstall cabinets and built-ins.

(Option 4: same as option 3, but turn it back into a multi-unit building and rent out part of it!)

Greg

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Re: Interesting Floor Dillemna
« Reply #4 on: March 03, 2014, 08:25:03 PM »
I'm with Jack.  It sounds like continuing to band-aid the concrete overlay is a downward spiral.   About the hidden hardwood, with stain it might be salvageable.

soccerluvof4

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Re: Interesting Floor Dillemna
« Reply #5 on: March 04, 2014, 03:58:34 AM »
I think the hardwood would be trashed. I think its a ton of work but take it down to the floor joists, remove the cabinets and redo but do it right. You could always etch and stain the concrete with an overlay but thats a look you would have to like and evaluate once the bamboo is up.

thelamb

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Re: Interesting Floor Dillemna
« Reply #6 on: March 04, 2014, 08:11:14 AM »
Thanks for the thoughts so far.  I'm definitely getting the sense that going over the concrete is not a winning idea.  Obviously, I would love to go back in time and address this situation before I built and installed as much as I did.  Ripping out all the cabinets and built-ins and starting over would give the absolute best result, but it just doesn't seem feasible; the thought is downright depressing.  I really feel though that I can remove the concrete around the various existing structures, leaving them on the 4" block of concrete.  I'm attaching a drawing of how I think this could work.  I'd be curious to see if anybody has done something similar or if there's any good reason why it's a bad idea. 


soccerluvof4

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Re: Interesting Floor Dillemna
« Reply #7 on: March 04, 2014, 08:32:47 AM »
I don't know , maybe its just me but seems to be alot of weight on those joists or I am not getting something here.  I think this one is out of my wheelhouse! Sorry couldn't help more. 

Milspecstache

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Re: Interesting Floor Dillemna
« Reply #8 on: March 04, 2014, 07:19:31 PM »
I don't know , maybe its just me but seems to be alot of weight on those joists or I am not getting something here.  I think this one is out of my wheelhouse! Sorry couldn't help more.

I would definitely not recommend putting further weight onto those joists!  4" of concrete was probably too much already.  Think about roof rafters where you can put (in my area) three layers of shingles before being required to do a complete tear-off.  That shingle weight is nothing compared to 4" of concrete... which I believe is around 50lb per square foot.  So 850sqft becomes 42,500 lbs!

Mrs WW

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Re: Interesting Floor Dillemna
« Reply #9 on: March 05, 2014, 03:59:48 AM »
And lookie, you just found yourself a real live architect right on this forum!

My professional two cents: You need to bite the bullet on this one and redo everything the right way. Take all the concrete out, even under the interior walls and cabinets and then screw in nice solid soft wood floors. The new floors will help strengthen the construction.

The concrete on top of the wood structure not built for it will never stop moving due to too heavy loads and the material difference in expansion/contraction over the seasons.

Its a hard lesson for you with lots of hard work, but you'll learn a ton doing it!

thelamb

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Re: Interesting Floor Dillemna
« Reply #10 on: March 05, 2014, 07:04:12 AM »
Thanks guys.  I assume those saying not to add weight are saying they are against the option of refinishing the concrete with an overlay product.  If not, there might be some confusion.  Currently, there is a 4" block covering the entire first floor, which is heavy. 

@Milspecstache: 
Quote
which I believe is around 50lb per square foot.  So 850sqft becomes 42,500 lbs!
 

No clue if this is right, but I wouldn't argue.  It's just a lot of weight.  However, the concrete has been there for over 60 years (building itself over 100) and the structure has been reinforced with over 30 jacks and other additional supports.  It's been certified by a structural engineer and there's no evidence of further shifting or settling.  There is; however,  settling and shifting with the bamboo product on top of the concrete. 

What I'm proposing is actually hacking out most of the weight.  I'm attaching another picture that shows how the vast majority of the first floor gets cleaned out, leaving four distinct concrete blocks, which would probably result in a 75% reduction in weight.  The question is can I cleanly hack out and cleanly tie the two frames together:  the existing blocks with the new wood frame, assuming a sub floor can slightly (at most 2-3") overlay the concrete block.

@Mrs WW - You're not the first to suggest starting over.  In an ideal world where I am FIRE and have the cash set aside, sure, I'm 100% with you, but the reality is I can at most afford a redo of the floor alone or I need to start thinking about listing and getting out.   

paddedhat

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Re: Interesting Floor Dillemna
« Reply #11 on: March 06, 2014, 06:46:03 AM »
As a builder my first thought was, OMG, who would pour 4" of concrete in this situation, and why did you do anything other than tearing it out before you started any rehab.  Once you explained all the subtle details....... engineer's inspection, thirty added supports, sixty years since this dumb idea was first completed, a complete new interior build-out on top, etc, things look a bit different.
My suggestion will cost you a few hundred bucks, and may turn out great, or not...... The goal is to strip back to the concrete and do what it takes to make it an interesting, attractive surface. After you strip all the existing finishes off, it's time to sand the crete.

Warning. DON'T do this if you are not 100% sure that you will not be sanding any existing asbestos bearing tile glues. The age of the slab, and it's prior use as a grocery, strongly suggests that it may of have a finished floor of composite asbestos tile, at one time. These tiles look like the boring old tile many of us remember from our elementary school classroom, and they were often glued down with glues that contained asbestos.  Typically this would of left a black tar like glue behind, and a lot of shadowing of the old tile.

Now it's time to sand. Most folks have no clue that you can use the very same tools and techniques to sand a wood floor, or a concrete one. Specifically, you use a giant commercial buffer, and a sanding screen. Sand the floor until it's as smooth, clean, and attractive as you can make it. Next it's time for a stain, preferably something very dark, like an Ox blood or dark leather color, and a few coats of clear.

May sound off the wall, but I'll bet it will end up pretty amazing. Good luck.   

Milspecstache

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Re: Interesting Floor Dillemna
« Reply #12 on: March 06, 2014, 07:41:13 PM »
That's what I have in my house...  ground floor is acid-etched concrete followed by polyurethane.  Looks good but is prone to scratches.  Regardless it is pennies per sqft.