Need advice big gaps wood floor and dirt floor basement

Tammy Richards · 2016-04-22T18:32:29-07:00

Have a 4 unit multi built @1900. Wood refinished floors have huge gaps/cracks, and they are layed over what appears to be what was called a subfloor in the Victorian era, which is wood which also has gaps. From the basement, I can see straight through these gaps to the apartment. The basement has a dirt floor. I want to lay floors (hopefully myself) on top of the wood floors, to improve air quality and cleanliness - vinyl plank will be fine for my section 8 tenants. Would like to lay vinyl plank or floating engineered myself I'm fine with filling gaps from below the basement in with Great Stuff or something, but hoping to avoid laying in a plywood subfloor (I don't have the tools, equipment, or time for that). Wondering if sealing gaps with great stuff and putting an underlayment which is also a moisture barrier would do? Flooring is pretty level, and in good condition. I'd appreciate recommendations/advice from folks.

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Contractor · Raleigh, NC · Member since 2014 · 651 posts · 510 votes

10y

@Tammy Richards I don't think you should put a third layer of flooring down. That's a lot of weight on an old floor and you will have numerous height issues (doors,stairs,cabinets,toilets,etc). Best to tear up the existing HW and lay your new floating floor over that (with the appropriate vapor barrier/foam padding). I'd also put down a vapor barrier over the basement dirt floor, at a minimum to help control moisture. I also wouldn't use Great Stuff; it will do little more than make a big mess.

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Andy Hudgins

Covington, GA · Member since 2015 · 99 posts · 33 votes

10y

@Tammy Richards

The old, "charming" floors are not the problem --- the dirt basement floor is. Heat rises in a home so it "draws" or "sucks" directly at the floor level. It draws air out of the basement through the leaky floor and carries moisture, mold particles, and other airborne STUFF with it. Please search "stack effect". There's lots of very small air passages in the floor you cannot see, same as with all floor systems over a crawl. The floor isn't broken, the building envelope is. There is no "boundary" on the lowest portion of your investment. There's no barrier between the earth, elements, and your investment.

Look into

http://www.crawlspacedepot.com/

I've got older posts on this topic. If I can help regarding specifics of this type of installation let me know. FYI the large, nationwide installer of this type of product are a money printing machine.

Andy

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Jassem A.

Investor · PA · Member since 2013 · 1k+ posts · 602 votes

10y

I wouldn't worry too much about the cracks if they're smaller than an inch. I'd go over top with a thick laminate or engineered flooring and lay the boards in the opposite direction of the existing hardwood because it tends to do better that way on uneven hardwood.

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JD MartinBusiness Member

Moderator

Rock Star Extraordinaire · Northeast, TN · Member since 2015 · 10k+ posts · 16k+ votes

10y

You would be better off adding 2 vapor barriers - one in the basement and one underneath the flooring you are about to install - than trying to mess with filling the gaps with foam sealant.

The right way to do this would be as mentioned above - remove the upper floor, drop a new plywood/OSB subfloor on top, and then install your vapor barrier and new flooring. If you're not going to do that, I would go with a thick poly liner covering all of the basement floor, climbing up the walls and sealed to the walls, and then an underlayment between the flooring and your vinyl, even something as simple as roofing felt, which is thin and easy to work with.

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Andy Hudgins

Covington, GA · Member since 2015 · 99 posts · 33 votes

10y

Well, Ms. Richards, do you hate the existing floors or are you just hoping to improve air quality and energy efficiency? Do you have old-growth heart pine that SHOULD stay or something different? We need to know that. Are we trying to kill two birds with one stone, replace floor AND improve air quality/energy efficiency?

Now, all the old flooring guys and all the manufacturers will tell you that you have to have a vapor barrier installed on the subfloor before you install your finish. That's true BECAUSE the crawl space/basements are never lined/encapsulated and dehumidified. Buckets of moisture are migrating up out of the soil into your investment(lay a 2' x 2' piece of clear plastic on your lawn in the middle of summer and watch how quickly water droplets form on the underside). But, maybe you want to keep what you've got ---- the floors are fine! Seal basement, line, up the walls, seal the foundation vents (definitely) and dehumidify(HEPA filter will remove micro contaminants) .

If, IF!, you are replacing the finish floors, that's a completely different conversation, one with the entire building health in mind especially with regard to how you treat the subfloor and regarding the addition of a second vapor barrier.

I hope this helps.

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Need advice big gaps wood floor and dirt floor basement

Need advice big gaps wood floor and dirt floor basement

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