Here is my dilemma: my kitchen/dining room floor has two large valleys that were framed into the floor (house built in 1959) that I need to level prior to installation of Forbo Marmoleum Click floating floor panels. The room is about 9.5′ by 29′. the valleys are definitely not the result of post-construction settling or other movement.
The valleys are from framing errors where the basement transitions from full height basement to crawlspace and then has to work around a large brick fireplace, while compensating for a sunken living room next to it (ie. not the most straightforward framing situation).
The largest valley is about 9′ wide and dips a little over 3/8″ from exterior wall to interior wall (and center of the house). The valley is between where the floor transitions from full height basement and where the framing is referenced to the fireplace (which is approx 8′ wide).
While the Forbo will accomodate 1/8″ slope per meter, the ‘sides’ of this valley are quite steep and therefore the valley needs to be filled.
To further complicate the matter, the subfloor is 3/8″ plywood topped with 5/8″ particle board. This subfloor is used everywhere in the house except the bedrooms that have hardwoods. The particle board goes underneath the kitchen cabinets so removing it would require a gut and remodel of the kitchen–which is not an option.
This floor was initially covered with 12″X12″ vinyl tiles that were removed about 35 years ago. The floor was then carpeted, first with glued on rubber carpet pad, then later with foam pad and carpet. The floor has been scraped as clean as possibly, but still has two types of mastic on it as well as small amounts of old rubber padding.
Because of the size of the valley and the subfloor condition and materials, using levelling compound is not an option. One local contractor suggested using roofing shingles to fill the bulk of the valley and then “feather” the edges with roofing felt and rosin paper.
I’ve put down a portion of the floor and the shingles seem to work fine, but I can still feel the floor flex where the roofing shingles “step down”. I could probably add more felt to try and even that out a bit though.
My questions to you all are:
1) Are shingles as good as anything to fill such a depression in the floor?
2) Are there other ways to feather the edges?
3) Would I be better off adding a layer of 1/4″ plywood over the shingles and then well nailed into the framing to give the floating floor the most support
This dilemma has been a head scratcher for several people here so any advice would be most appreciated.
Replies
I recently fixed a dip in a bedroom floor by removing the subfloor, shimming th floor joists with strips cut from a 2X4 and glue, and installing new subfloor (sturdifloor) over the shims.
Don't discount the idea of tearing up the underlayment. See "toekick Saw" at the local rental place, designed to cut the underlayment back nearly flush with the back of the toekick. this would let you address the underlying problem and install proper underlayment. also dissapear all that goop on existing. Jim Devier
I had a two floors that required 30 bags of leveling compound to true them up for a floating laminate sytem (100 year old house).
You might want to reconsider this avenue. I nailed down wire lath in the low spots. Then I got myself two clean drywall mud pails. I marked a plastic container so that each batch would have exactly the same amount of water being added to each pail. Used a Milwaukee d-handle drill with a mud mixer to mix. With two people (one mixing, one pouring the mixture onto the floor) it goes pretty quick. But you have to move quickly because the stuff starts setting up in like 15-20 minutes. One important note: Before installing wire lath, put tape over ANY crack, hole, etc., or the leveling compund will run through it and end up in the living space below. Trust me on this - the mixture is slightly stiffer than water before it sets up.
This whole mixing process works alot better if you can use a hose and mix outdoors, then carry the mixture inddors.
The finished product will be about as level a floor as you can get.
DIA
Same problem once, same age house. We set level 2x4s screwed to the wall made a screed out of another 2x4 that ran on the rails and floated cement. It didn't set as fast as the floor leveler and it was alot cheaper. Screwd down an underlayment (1/2" or 1/4" can't remember) and then the new flooring- lino I think. I can't remember the mix we used...but it was smooth and stone free. Must have been a sand mix of some kind.
I've done that, too. Works better on square or rectangular rooms than one with jogs, etc. As far as setting the side rails, that is. And yep, that self-leveling floor stuff is a little pricey. Home Depot wanted like $28.00/bag! I went to a big tile place and paid just over $16.00/bag. You have to love how level you can get a floor with really minimal effort, if you think about it. Every once in a while a fella needs to accomplish a task that works well, works quickly, and that is really hard to screw up (unless you miss a crack with the tape!)
DIA
thanks for the advice. If I go this route I'd be putting the levelling compound on particle board so would I need to take any additional precautions so the PB doesn't dissolve. With all the mastic on it, there is already a pretty good sealer on it, but it isn't uniform. That seems like a lot of water to be putting onto PB.Also, would it matter if the compound or concrete later comes loose from the underlayment? The floors are pretty bouncy (2X8's 16" OC with almost no blocking) and with all the junk on the surface, I can't imagine it bonding tightly forever. I'm going to be adding some solid blocking in the near future, but that will only dampen the movement.I haven't totally ruled out pulling up the subfloor, shimming the joints and then putting in new subfloor, but the levelling compound sounds like a whole lot less work. the subfloor is ringshank nailed every 8"
I vote for pulling up the PB underlay. The stuff is garbage, and yours is covered in dry mastic to boot. Once it is up you could float a mortar bed over diamond lath to fill the low valley, then pour a smaller quantity of the high-dollar self-leveling stuff over everything to get things perfect. If you have access, for sure do some blocking first. To recap, I'd put the lath everywhere, float the lowest spots with floor mud (cheap) wood-floated for tooth. Let that cure overnight and then cover it all with the self-leveling underlayment. This will also remove some of the bounce from the floor.This project can be easy, or cheap, but not both. My solution splits the difference.Bill
Yea, I'd expect bouncy floor with 3/8" plywood on 16"oc joists! I'd vote for a do-over. Yank the pb and the plywood, shim up or sister the joists then lay down 3/4" plywood or advantec + 1/4" hardboard - that will get you back to the original floor height.