Off Level Help

[tkcenterline]

They just delivered my new Grandee hot spring tub today. The problem is that my new 16' x 16' x 6" concrete patio was installed and the center is crowned by a 1/4" high, which causes the tub (dry) to wabble from side to side about 3/8" of an inch. So when level, the center of the tub is on concrete but the last 1'0 on each end is about 3/8" above the concrete. How do I fix this in a manner that is good for the tub in the long run. The manufacture said to grout it in. The tub installer said to fill it with water and the tube will give and settle for 3/8" (ea side). I want to do the best for the tub and for the long run. Any answers on the best way to solve this rocking problem. I can't believe the concrete can only be 1/4 off and the tube wont set level??

[Dnepr Dave]

They have machines that will grind the concrete flat, or you can add cement to the edges to flatten it out, grout.

I certainly wouldn't fill it and let it settle!

Dave

[gman]

tkcenterline,

I am not intimately familiar with the underside of the Grandee. But these are my thoughts on your problem...the things I would consider if I were in your shoes....

With your slab having a crown or ridge in the center, either i) the tub has to conform to the slab or ii) the slab can conform to the bottom of the tub.

It seems the manufacturer wants you to follow "ii" while the tub installer (dealer?) suggests you follow "i". My inclination would be to follow the manufacturer's advice. I would assume that since they built the thing, the manufacturer would be more knowledgeable with the tub's physical characteristics than the tub installer.

But before I would go through the trouble of grouting a large section on my slab, I would call the manufacturer's technical section and ask a generic question about the flex tolerance of the tub on ANY surface that might not be perfect. The tub must have some ability to adapt to uneven ground. Not all tub base surfaces are perfectly flat, smooth, and level. You may find that the tub is flexible enough to adapt to your slab as the tub installer suggests.

If your current slab condition puts the tub outside the adaptability tolerance suggested by the manufacturer, grouting may be a solution, but perhaps not the only way to level the slab.

If the high point of your ridge or crown is not too massive a section of the slab, an alternative to grouting may be to simply grind the slab to remove the high ridge or crown. You can put a laser across your slab to find the high point(s) of the ridge or crown. You may find that you would only have to grind a small amount of slab to meet the flex tolerance range as stated by the manufacturer. The down side to grinding is that it requires special tools and is a dirty & dusty alternative compared to grouting.

Another alternative to grouting would be to put another layer of "finish concrete" that removes the crown and levels the entire slab. You could make the new finished layer a designer/decorative concrete pattern thats colored to look like installed tile or stone.

Just my thoughts.

gman