Yet Another Patio question

[tmaestas95]

Hi All,

Getting ready to purchase what I believe will be a Bullfrog R8 (same size as the A8, 2 fewer jetpacks,  94"x94").  My intended location is an existing concrete patio.  It has a slight slope, probably not more than 1/2" over 8 feet, however what concerns me more is that the area is also probably not completely flat.  There are very slight dips in the area, none more than 1/2" best I can tell.  All I've read seems to indicate the most important factor is that the tub be evenly supported across the entire base.  Would a few very slight 1/2" dips be a concern?  I've pretty much convinced myself that they are (a concern), since I don't want to risk this much of an investment - in which case I would probably proceed with building a frame out of PT 2x4 or 2x6's and filling with 3/4" crushed aggregate, which brings me to my second question - how easy is it to level off crushed rock?  I'd hate to trade my existing "mostly flat and mostly level" patio for a "mostly flat and mostly level" crushed base.  Would it be easier to level off if I went with sand over the crushed rock and laid pavers?  Also, since again the patio has slight dips, should I be concerned about some of the very small gaps that the wood frame would have while on the ground?  Should I line the frame with landscape fabric or use silicone or expanding foam?  I've seen older posts that suggested these tips both but never saw what the OPs ended up with.

Thanks for any guidance.

[BullFrogSpasMN]

Another option would be to measure out the exact 8' x 8' where the spa will sit and use this: https://www.quikrete.com/productlines/concreteresurfacer.asp  normally I wouldn't recommend a "quick fix" but small 1/2" dips could easily be leveled out with this product, if your slab was chipping away/cracking/heaving/etc. then I would recommend a longer term solution but that doesn't seem to be the case...good luck, I've sold/delivered 2 R8's in the past month, awesome big tub!

[htnj]

Is this a patio tied in with a larger patio?  I'd be concerned how thick it is and the subbase.

If it were me, I'd demo that area, add crushed aggregate, and re pour so I knew that area was sufficient. Also, in many towns, if there is concrete surrounding the tub that you can walk on, you need to have an equipotential bonding grid in the concrete.  Just some things to think about.

[Dr. Spa™ Ret.]

What's the difference between, "a few very slight 1/2" dips" and a "a few 1/2" dips"??

[KDFrosty]

I did nearly exactly what youre describing, but started with a compacted dirt (removed sod) base.  Built a 10'x12' form out of PT 2" x 6" lumber.  Filled 2" with inexpensive 7/16 crushed gray aggregate, then leveled using a straight 10' 2"x4" and the longest (4') level I own. Rented a 12" plate compactor and compacted the whole area.  Did minor readjusting to hit level again. Placed the tub.  Filled the remainder of the form with rock that more closely matched my xeriscaped yard.
Just a couple weeks ago:

[KDFrosty]

Duplicate post, sorry.

[tmaestas95]

What's the difference between, "a few very slight 1/2" dips" and a "a few 1/2" dips"??

Just my imprecision

To the naked eye the area seems pretty flat - but a 2x4 laid on the ground has some very small areas where daylight is showing under.  The patio is tied to a larger patio, 4" thick, no cracks or other notable deficiencies - and I live in California where the weather is pretty mild.  I really want to convince myself that the tub would be fine placed directly on the patio, but better safe than sorry I suppose.  i'd really rather not rip the whole thing up as there is a pergola over the top which would complicate things, so I'm still leaning towards a form with crushed rock.  Is tamping with a hand tamp an option or is it really better to rent a plate compactor?  Any advice on potential gotchas for doing this on top of concrete (as opposed to on a dirt base)?

The quikrete resurfacer idea is an interesting idea, I'll have to look into that some more...

Thanks for the feedback.

[Compatico]

The quikrete resurfacer idea is an interesting idea, I'll have to look into that some more...

Another one is called Topbond...I've used it in the past to repair a cracked garage floor with a 1" drop where the crack appeared. Some 10 years later my friend says it's still solid as any other garage floor they've seen and no issues. I'd just resurface adding a little to compensate for the slope and try to get it dead level.

Originally I was thinking of a crushed gravel base in a pressure treated frame, but since this will likely be my last house and tub placement, I'll probably go with a concrete pad even though it'll be more of a hassle getting it done.

[htnj]

yeah with a 4" pad I think you're fine.  I'd also probably just resurface.

I don't know what your plan is as far as getting the proper permits.  But in my town, if there's concrete around teh tub, I'm required to have bonding grid in the concrete.

Just something to think about if you're going the permit route.

[Tman122]

What do you mean by "going the permit route"?...........LOL Any city inspectors hanging around the board? Where safety is concerned for sure know the codes and the reasoning behind them going in, following them is a choice.

[Jacuzzi Jim]

 I hate permits.  I just dropped 170.00 on one for the roof I put on two years ago. Were doing a re-fi on the house and the appraiser caught that I didn't pull one.  So the inspector came out today spent 8 min looking at the roof and another 2 min filling out the paper work. That's 17 bucks a minute       I understand they are needed, but for things like that no way.

[tmaestas95]

I have an email in to my city to see what they technically require permit-wise, but....well....we'll just see what they say.  I would for sure like to get my electrical permitted, I just hope that the electrical inspector doesn't turn around and ask about an installation/building permit for the actual tub install (assuming one is required).

[htnj]

It's going off topic, partly my fault (sorry), but for me I can't just pick and choose what to get.

Like I can't just have electrical inspected, it's all or none.  And for me, all was: electrical, plumbing, building, and zoning.  $173 + $50 to zoning.
I'm all for safety, but this is just crazy!

[tmaestas95]

I had the city tell me today they want a building permit for the tub - at an estimated cost of $800!  And that's before the electrical permit.  You want to talk about crazy?  After hearing that, I'd jump for joy if they had told me ~$250....

[Tman122]

I had the city tell me today they want a building permit for the tub - at an estimated cost of $800!  And that's before the electrical permit.  You want to talk about crazy?  After hearing that, I'd jump for joy if they had told me ~$250....

Did you tell them it was a portable hot tub?