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My sunken living room floor is concrete slab surrounded on two sides by higher concrete slabs at the level of the rest of the house. The other wall is a brick fireplace hearth. The wall opposite that is a sheetrock exterior wall. It is an area about 13' x 10' which is much too small for a "sunken" anything in my book and is just a hazard for an old woman (me) to fall into. One of the concrete side walls is the entryway at the front door and is far too narrow as well. I want to raise this floor to the level of the rest of the house and I have ceramic tile to do throughout the house. This area is about 6 inches deep. What is the best and possibly cheapest way to fill this in and level it off?

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    I am not sure what architectural phase required a sunken living room with a fireplace.... I have one too. If it is only sunk 6" that actually makes it a bit harder but it is still doing pretty cheap for a 13'x10' space. – DMoore May 22 at 4:32
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    Are there any electrical receptacles in the sunken section which would be at or near floor level were it to be raised? – Matthew May 22 at 5:08
  • Pretty sure this came up a couple years ago in this site - perhaps someone with Close permission can track it down? – Carl Witthoft 2 days ago
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    I highly recommend against doing this by pouring concrete, but if you do, note that 6" is waaay too deep for self-leveling compound alone. – Timbo 2 days ago
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    @Carl: I don't see anything obvious in a search. But regardless, you don't need enough rep to vote-to-close just to find the post. If you do the work and find an actual duplicate, maybe others who can VTC will do so once you flag the post as a duplicate. It's a bit much to simply hint that the post might be out there, and then expect someone else to do the work to actually find it. – Peter Duniho 2 days ago
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One way to raise the floor, and possibly the most reasonable cost wise, is to install what I would call sleeper joists sitting the top of the existing subfloor and than add new subfloor covering over those.

These "sleeper joists" would be installed as 2xX material on edge. This could be 2x6 planks spaced 16" apart. It may be necessary to rip the 2x6 planks to somewhat less than their native 5.5" width so that the subfloor and whatever flooring that you choose to put on top of that would match to the adjoining floor heights.

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    This is what I would go with, too. I would think that construction adhesive between the 2x and the concrete floor to keep the joists from moving and possibly squeaking would be a good value added step. – FreeMan May 22 at 12:07
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    Put in a few orthogonal braces here and there to keep the joists from walking – Carl Witthoft 2 days ago
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    In the process, you can build in access to underfloor storage. – Phil Freedenberg 2 days ago
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    This might require also raising or closing the fireplace. – Timbo 2 days ago
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    And... this should be pretty reversible, in the event sunken areas suddenly become a 20% value add to a house. – Eric Hauenstein 2 days ago
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So its a shallow concrete pit in the floor? With concrete on five sides? I would fill it with concrete - either straight concrete if it was shallow, or put a layer of gravel in to save on expensive concrete.

Downsides, this is likely to cost a lot more than the wooden floor suggested already, but you could park a car or grand pianos on this without concern. Also, its NOT easily reversible like the timber solution.

Since the area is backed by concrete already, you might get away with no reinforcing in this, though I'd probably lay some mesh in there anyway. You would use a suitable etching fluid to "key" into the existing concrete surface.

The hardest part would be getting the fill and liquid concrete into the room. That would be a lot of stone to move.

A square yard of gravel with a depth of 2 in (~5 cm) weighs about 157 pounds (~74 kg).

concrete is about 150 pounds (72 kg) per cubic foot

You have roughly 3 yards x 4 yards, so 12 square yards and 4-5 inches deep which is about 4700 pounds or 2200 kilograms of gravel.

Concrete on top would be between 1600 pounds for a 1" thickness, and 3200 pounds for 2"

A contractor's wheelbarrow full of wet concrete is around 80 lbs.

So you'd have to carry very approximately 75 contractor wheelbarrows of fill and 25 barrows of concrete through your house to the area.

I'd build a shallow ramp to go over any door steps, and would line any access routes with cheap plywood on the floor and plastic up the walls to save damage. You would also want to completely empty the destination room of furniture, and cover at least the lower walls and fireplace.


What have I missed about pouring new concrete butted to existing concrete? Given its a solid box already, there's little need to tie the old and new together with anchors. And the new concrete is only going to be subject to compression not tension.

The concrete will take a couple days to cure, and then up to a month to cure completely. If you find the lime-smell of concrete unpleasant, you might want to sleep elsewhere for a bit. Venting the room via open windows and breeze will help.

Expect to not walk on it for days, and leave it uncovered for as long as possible. Perhaps throw some temporary carpet on top, but I would not start tiling for at least a month after initial pour.

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    I wouldn't recommend concrete for this - a lot more expense and labor than the wood framing approach, with no additional benefit. Plus there's higher risk of damaging something with spills while mixing and moving the concrete, and the space is taken out of operation for 2-3 days while the concrete cures. Perhaps more critically, no one knows if the foundations were designed to accommodate an extra 4-5 tons in that room, so there's a real risk of causing settling damage as well. – brichins 2 days ago
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    This area is just a 10 x 13 rectangle with three sides concrete and one side sheetrock with windows over that area. No electrical outlets in the way. Windows directly on one end of the project should allow access across the front yard for a pumper truck so no wheelbarrows of concrete. Nothing to damage the whole way. It would take roughly 2.5 yards of concrete. I figure around 300 bucks tops. Is wood less than that? At this point its labor time and the weight of concrete causing a problem v/s carpentry skills and cracking floor tiles that seem to be the main considerations. Thoughts? – Mary Shelton 15 hours ago

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