[Shop-talk] Flooring for uneven basement?

[Jim Franklin]

On Dec 6, 2010, at 2:29 PM, David Scheidt wrote:

> On Mon, Dec 6, 2010 at 12:47 PM, Jim Franklin <jamesf at groupwbench.org>
wrote:
>> I'm renovating a basement and need to put down a finish floor. The concrete
is
>> 90 years old and very uneven.
>
> Put some numbers on that.  How big are the differences, is it pitched
> from side to side (or center to sides), does it have big uneven bumps
> and holes, or what?  If it's flatish, and just not level, you can put
> a number of things (like a floating laminate, if it's dry) down.  The
> resulting floor might pitch, but that's not always awful.

THere's too much stuff down there to tell if it pitches overall, but the
localized differences (holes and humps, mountains and valleys) are no more
than 3".

>
> Self-leveling stuff is very expensive, and for big areas, with big
> holes to fill, trowelable stuff works fine, is cheaper.  Don't forget
> to consider lowering the high spots.

The high spots are too wide. Think Appalachians, not Rockies :-)

I think troweling in the depressions to make it shimmable is the best option.
Advantek over sleepers should be sturdy enough, but I'd sure love a recessed,
top-adjustable threaded fastener. Something like a locking (like Nylok) T-nut
on 16" centers, whose protruding shaft I could cut off once the adjustment was
done. Actually that might work if she doesn't balk at the cost...