[tawolcott]

I've seen a couple threads on this but I don't think any specific to my situation. Here goes.

Area is roughly 40X16 extending from house to inground pool deck. There is an existing 12X12 concrete pad in the middle of the area (right now a 20X16 deck exists above the concrete pad, will soon be gone.. has been there for 10 years).

Concrete pad has the required slope for draining and is in excellent shape.

The concrete pad is approx 10 inches below the final grade of the paver to meet the existing pool deck (with required slope). So there will be base material on top of the concrete. Attaching to the pad is not possible.. Nor is removal (sorry)

Questions:

1) I have read that it is ok to go over the concrete pad.. but have also been reading of base washing out from the water run off on the pad. With 6+ inches of base material over the pad will this be an issue?

2) Should I bury a drain pipe at the end of the pad ? There will be approx 3 feet between the end of the pad and the beginning of the pool deck.

3) Should I be careful to have the pavers match the form of the pad, or should I try and have then span concrete base - non-concrete base?

4) Should the membrane cover the concrete as well. Had heard a suggestion of perhaps putting a 2 inch compacted layer down, then the membrane over the whole thing.. then the final 4+ inches of base ?


Right now the stairs were planned to be left-right and not the traditional str8 down .. but if they were to be str8 out and down it would take up more of the concrete pad and thus leave more of the pavers on virgin earth.

Escavation is almost complete.. So , final planning is getting underway.

Any opinions would be appreciated.

[fitzg2md]

personally, i would be vary weary of using a 10 year old pad as a starting point to any new construction. Removal of such a small pad would be simple i would think, and may save you some trouble in the future...though as youve stated that isnt an option...

[cutntrim]

If removal of the pad isn't possible, what about building a raised SRW wall all the way around the edge of the pad going 10" above the concrete surface, then infill with aggregate and lay your bricks after that. It would eliminate the worry of "washout" and may even look nicer-to-boot.

[tawolcott]

Don't I have the same possible issue though? Base material on the slab that does extend all the way to the pool deck.. ie 16 ft deep.... 12 ft is slab (10" below final grade), 4 ft is earth 10-ish " below grade). That's where I worry about the wash out.. from the water run off of the hard slab thru the base .

The Geo may bridge the gaps..

[tawolcott]

Opps... sorry .. read that wrong..

[tawolcott]

I like that.... very much

[PSUscaper]

I'm not positive, but what I think you are planning to do is just bury the concrete pad underneath the new patio, which will cover a area larger than the pad.

If this is the case, I would plan on removing it.

Have you ever driven down a highway that was a ovelay of asphalt over a old exis concrete road? If you have, then you see what happens. Where the new aphalt/base material extends past the concrete, you get a heave. Also, where ever there was a expansion joint in the the concrete, you get a heave.

This is a 12' x 12' pad........hardly a big job to remove. If you look at the long term risk of the pad heaving up the bricks above it and the cost of repairing it, it should easily out weigh the cost of removing the pad. If this is a budget conscious customer who is concerned about cost, then leave it....but get him to sign off on the consequences. If you believe in doing a quality job, and your customer is paying you to do so, take it out.

I would take it out without thinking twice. I also have to ask why removal is not possible? This sounds like a decent size job. Are you telling me that removing a 12 x 12 concrete pad (about 3 yards of concrete if 6" thick) is going to break the budget? That you don't have a machine capable of doing it? That you can't rent a jackhammer for the day?

I have to say, that hearing this, makes me a little nervous on the rest of the project. If this question were on the homeowner forum, I may be a little bit more willing to understand that its a lot more work to take out and that it may only cause slight problems....but this is a place for professionals, and hopefully, you will listen to the advice given, as it has be gained through years of experience.

[ckcland]

curious... why is removing the pad not an option. Should be easy to remove with forks on skid steer, lift slightly, break.. then pick up pieces. That would be my 2 cents anyway.

good luck.

[dan deutekom]

To me removing the pad isn't even a question. It is an assumption that it goes. No matter what you do, leaving the pad will haunt you down the road with heaving problems.

[AZTLANLC]

I'm looking for a picture where I did kind of the same, you can actually see where the concrte pad is.

I was stupid enough to leave the concrete and extend the patio, that was before GTX and ICPI.
Listen to this people they really know what will happen.

[cutntrim]

You know what, when I suggested boxing-in the pad and laying pavers over top as a possible solution, I didn't take into account that you want to actually extend the area beyond the size of the existing pad. That'll teach me not to speed-read posts.

With that in mind, I would agree with others that you'd be opening yourself up to settling problems where the extended portion would in time no longer match up flush with the part over top of the pad. So disregard my original option and go with the demo-first plan.

Fortunately, unlike AZTLANLC I've never extended a patio over poured concrete and had it heave. However, there was a job a couple of years ago where we discovered a mysterious "foundation" for lack of a better term on a backyard patio job. I did run the pavers over top in that case but first I actually raised the grade of the entire patio to allow for that, so the foundation/wall underneath was no longer at the surface. The homeowner, nor I had any idea what the foundation would have been for. It was a square about 5'x5', open in the center like a big sandbox. The concrete went down about 24" too so I wasn't about to try and break it out of there. After discussing it with the homeowner we decided to leave it in.

[tawolcott]

ok, I removed the concrete patio.. now I have a 6" depression in part of the paver area.. Should I fill/compact that with base material to get everything 'level' before the geo?

How much of the concrete pieces (small) can I safely leave?
There is also a inch or 2 base of fine (quarter inch) stone under the slab... does that need to go too, or will the base filter in during compaction and tighten that up?


BTW: not all jersey is sand.. I got nothing but clay 6 inches down

[ckcland]

I recommend you look for your nearest ICPI or EP Henry certified contractor and give them a call. Sounds like your in over your head. Sorry but honesty is needed here. You'll only dig yourself deeper as you get closer to the pool.